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gpg(1)





NAME

       gpg -- encryption and signing tool


SYNOPSIS

       gpg  [--homedir name]  [--options file]  [options]  command  [args]


DESCRIPTION

       gpg is the main program for the GnuPG system.

       This  man page only lists the commands and options available.  For more
       verbose documentation get the GNU Privacy Handbook (GPH) or one of  the
       other documents at http://www.gnupg.org/documentation/ .

       Please  remember  that  option parsing stops as soon as a non option is
       encountered, you can explicitly stop option parsing by using  the  spe-
       cial option "--".


COMMANDS

       gpg  may  be run with no commands, in which case it will perform a rea-
       sonable action depending on the type of file it is given as  input  (an
       encrypted  message  is  decrypted, a signature is verified, a file con-
       taining keys is listed).

       gpg recognizes these commands:

       -s, --sign
                 Make a signature. This command may be combined with --encrypt
                 (for  a  signed  and  encrypted  message), --symmetric (for a
                 signed and symmetrically encrypted message), or --encrypt and
                 --symmetric  together  (for  a  signed  message  that  may be
                 decrypted via a secret key or a passphrase).

       --clearsign
                 Make a clear text signature.

       -b, --detach-sign
                 Make a detached signature.

       -e, --encrypt
                 Encrypt data. This option may be combined with --sign (for  a
                 signed  and  encrypted  message),  --symmetric (for a message
                 that may be decrypted via a secret key or a  passphrase),  or
                 --sign  and  --symmetric  together (for a signed message that
                 may be decrypted via a secret key or a passphrase).

       -c, --symmetric
                 Encrypt with a symmetric  cipher  using  a  passphrase.   The
                 default  symmetric  cipher  used  is CAST5, but may be chosen
                 with the --cipher-algo option.  This option may  be  combined
                 with  --sign  (for  a signed and symmetrically encrypted mes-
                 sage), --encrypt (for a message that may be decrypted  via  a
                 secret key or a passphrase), or --sign and --encrypt together
                 (for a signed message that may be decrypted via a secret  key
                 or a passphrase).

       --store   Store only (make a simple RFC1991 packet).

       --decrypt [file]
                 Decrypt  file (or stdin if no file is specified) and write it
                 to stdout (or the  file  specified  with  --output).  If  the
                 decrypted  file  is  signed,  the signature is also verified.
                 This command differs from the default operation, as it  never
                 writes  to  the filename which is included in the file and it
                 rejects files which don't begin with an encrypted message.

       --verify [[sigfile]  [signed-files]]
                 Assume that sigfile is a signature and verify it without gen-
                 erating  any  output.    With  no  arguments,  the  signature
                 packet is read from stdin.  If only a sigfile  is  given,  it
                 may be a complete signature or a detached signature, in which
                 case the signed stuff is  expected  in  a  file  without  the
                 ".sig"  or  ".asc" extension.  With more than 1 argument, the
                 first should be a detached signature and the remaining  files
                 are  the  signed stuff.  To read the signed stuff from stdin,
                 use -  as  the  second  filename.   For  security  reasons  a
                 detached signature cannot read the signed material from stdin
                 without denoting it in the above way.

       --multifile
                 This modifies certain other commands to accept multiple files
                 for  processing  on  the command line or read from stdin with
                 each filename on a separate line.  This allows for many files
                 to  be  processed at once.  --multifile may currently be used
                 along with --verify, --encrypt,  and  --decrypt.   Note  that
                 `--multifile  --verify'  may not be used with detached signa-
                 tures.

       --verify-files [files]
                 Identical to `--multifile --verify'.

       --encrypt-files [files]
                 Identical to `--multifile --encrypt'.

       --decrypt-files [files]
                 Identical to `--multifile --decrypt'.

       --list-keys [names]

       --list-public-keys [names]
                 List all keys from the public  keyrings,  or  just  the  ones
                 given on the command line.

                 Avoid  using  the  output of this command in scripts or other
                 programs as it is likely to change  as  GnuPG  changes.   See
                 --with-colons  for  a  machine-parseable  key listing command
                 that is appropriate for use in scripts and other programs.

       -K, --list-secret-keys [names]
                 List all keys from the secret  keyrings,  or  just  the  ones
                 given  on  the  command  line.  A '#' after the letters 'sec'
                 means that the secret key is not usable (for example,  if  it
                 was created via --export-secret-subkeys).

       --list-sigs [names]
                 Same as --list-keys, but the signatures are listed too.

                 For each signature listed, there are several flags in between
                 the "sig" tag and keyid.  These flags give additional  infor-
                 mation  about  each  signature.  From left to right, they are
                 the numbers 1-3 for certificate check level (see  --ask-cert-
                 level),  "L"  for  a  local  or non-exportable signature (see
                 --lsign-key), "R"  for  a  nonRevocable  signature  (see  the
                 --edit-key  command  "nrsign"), "P" for a signature that con-
                 tains a policy URL (see --cert-policy-url), "N" for a  signa-
                 ture  that contains a notation (see --cert-notation), "X" for
                 an eXpired signature (see --ask-cert-expire), and the numbers
                 1-9  or "T" for 10 and above to indicate trust signature lev-
                 els (see the --edit-key command "tsign").

       --check-sigs [names]
                 Same as --list-sigs, but the signatures are verified.

       --fingerprint [names]
                 List all keys with their fingerprints. This is the same  out-
                 put  as  --list-keys but with the additional output of a line
                 with the fingerprint. May also be combined  with  --list-sigs
                 or --check-sigs.  If this command is given twice, the finger-
                 prints of all secondary keys are listed too.

       --list-packets
                 List only the sequence of packets. This is mainly useful  for
                 debugging.

       --gen-key Generate  a  new key pair. This command is normally only used
                 interactively.

                 There is an experimental feature which allows you  to  create
                 keys  in  batch  mode. See the file doc/DETAILS in the source
                 distribution on how to use this.

       --edit-key name
                 Present a menu which enables you to do all key related tasks:

                 sign      Make  a signature on key of user name If the key is
                           not yet signed by the default user  (or  the  users
                           given  with  -u), the program displays the informa-
                           tion of the key again, together  with  its  finger-
                           print  and  asks  whether it should be signed. This
                           question is repeated for all users  specified  with
                           -u.

                 lsign     Same  as "sign" but the signature is marked as non-
                           exportable and will therefore never be used by oth-
                           ers.   This  may be used to make keys valid only in
                           the local environment.

                 nrsign    Same as "sign" but the signature is marked as  non-
                           revocable and can therefore never be revoked.

                 tsign     Make  a  trust signature.  This is a signature that
                           combines the notions of certification (like a regu-
                           lar  signature),  and  trust (like the "trust" com-
                           mand).  It is generally  only  useful  in  distinct
                           communities or groups.

                 Note  that  "l"  (for local / non-exportable), "nr" (for non-
                 revocable, and "t" (for trust) may be freely mixed  and  pre-
                 fixed to "sign" to create a signature of any type desired.

                 revsig    Revoke  a signature.  For every signature which has
                           been generated by one of  the  secret  keys,  GnuPG
                           asks  whether  a  revocation  certificate should be
                           generated.

                 trust     Change the owner  trust  value.  This  updates  the
                           trust-db immediately and no save is required.

                 disable

                 enable    Disable or enable an entire key. A disabled key can
                           not normally be used for encryption.

                 adduid    Create an alternate user id.

                 addphoto  Create a photographic user id.   This  will  prompt
                           for a JPEG file that will be embedded into the user
                           ID.  Note that a very large JPEG will  make  for  a
                           very  large key.  Also note that some programs will
                           display your JPEG unchanged (GnuPG), and some  pro-
                           grams will scale it to fit in a dialog box (PGP).

                 deluid    Delete a user id.

                 delsig    Delete a signature.

                 revuid    Revoke a user id.

                 addkey    Add a subkey to this key.

                 addcardkey
                           Generate a key on a card and add it to this key.

                 keytocard Transfer  the  selected  secret key (or the primary
                           key if no key has been selected)  to  a  smartcard.
                           The secret key in the keyring will be replaced by a
                           stub if the key could be stored successfully on the
                           card and you use the save command later.  Only cer-
                           tain key types may be transferred to the  card.   A
                           sub menu allows you to select on what card to store
                           the key.  Note that it is not possible to get  that
                           key  back  from  the card - if the card gets broken
                           your secret key will be  lost  unless  you  have  a
                           backup somewhere.

                 bkuptocard file
                           Restore  the given file to a card. This command may
                           be used to restore a backup key (as generated  dur-
                           ing  card initialization) to a new card.  In almost
                           all cases this will  be  the  encryption  key.  You
                           should use this command only with the corresponding
                           public key and make sure that  the  file  given  as
                           argument  is  indeed  the  backup  to restore.  You
                           should then select 2 to restore as encryption  key.
                           You  will first be asked to enter the passphrase of
                           the backup key and then for the Admin  PIN  of  the
                           card.

                 delkey    Remove a subkey.

                 addrevoker [sensitive]
                           Add  a designated revoker.  This takes one optional
                           argument: "sensitive".  If a designated revoker  is
                           marked  as  sensitive,  it  will not be exported by
                           default (see export-options).

                 revkey    Revoke a subkey.

                 expire    Change the key expiration time.   If  a  subkey  is
                           selected,  the  expiration time of this subkey will
                           be changed.  With no selection, the key  expiration
                           of the primary key is changed.

                 passwd    Change the passphrase of the secret key.

                 primary   Flag  the  current  user  id  as  the  primary one,
                           removes the primary user id  flag  from  all  other
                           user  ids  and  sets  the timestamp of all affected
                           self-signatures one second ahead.  Note  that  set-
                           ting  a  photo  user ID as primary makes it primary
                           over other photo user IDs, and  setting  a  regular
                           user ID as primary makes it primary over other reg-
                           ular user IDs.

                 uid n     Toggle selection of user id with index n.  Use 0 to
                           deselect all.

                 key n     Toggle  selection of subkey with index n.  Use 0 to
                           deselect all.

                 check     Check all selected user ids.

                 showphoto Display the selected photographic user id.

                 pref      List preferences from the selected user  ID.   This
                           shows the actual preferences, without including any
                           implied preferences.

                 showpref  More verbose preferences listing for  the  selected
                           user  ID.   This shows the preferences in effect by
                           including the implied preferences of 3DES (cipher),
                           SHA-1  (digest),  and Uncompressed (compression) if
                           they are not already  included  in  the  preference
                           list.

                 setpref string
                           Set the list of user ID preferences to string, this
                           should be a string similar to the  one  printed  by
                           "pref".  Using an empty string will set the default
                           preference string, using  "none"  will  remove  the
                           preferences.   Use "gpg --version" to get a list of
                           available algorithms.  This command  just  initial-
                           izes  an internal list and does not change anything
                           unless another command (such  as  "updpref")  which
                           changes the self-signatures is used.

                 updpref   Change  the preferences of all user IDs (or just of
                           the selected ones to the current  list  of  prefer-
                           ences.   The  timestamp of all affected self-signa-
                           tures will be advanced by one  second.   Note  that
                           while   you   can  change  the  preferences  on  an
                           attribute user ID (aka "photo ID"), GnuPG does  not
                           select keys via attribute user IDs so these prefer-
                           ences will not be used by GnuPG.

                 keyserver Set a preferred keyserver for  the  specified  user
                           ID(s).   This  allows other users to know where you
                           prefer they get your key  from.   See  --keyserver-
                           option  honor-keyserver-url  for  more  on how this
                           works.  Note that some versions  of  PGP  interpret
                           the  presence  of a keyserver URL as an instruction
                           to enable PGP/MIME mail encoding.  Setting a  value
                           of "none" removes a existing preferred keyserver.

                 toggle    Toggle between public and secret key listing.

                 clean     Cleans keys by removing unusable pieces.  This com-
                           mand can be used to keep keys neat and  clean,  and
                           it has no effect aside from that.

                           sigs      Remove any signatures that are not usable
                                     by the trust calculations.  For  example,
                                     this  removes any signature that does not
                                     validate.  It also removes any  signature
                                     that  is superceded by a later signature,
                                     or signatures that were revoked.

                           uids      Compact  (by  removing   all   signatures
                                     except  the  selfsig) any user ID that is
                                     no  longer  usable  (e.g.   revoked,   or
                                     expired).

                 If  invoked  with  no  arguments,  both `sigs' and `uids' are
                 cleaned.

                 save      Save all changes to the key rings and quit.

                 quit      Quit the program without updating the key rings.

                 The listing shows you the key with its secondary keys and all
                 user  ids.  Selected  keys  or  user  ids are indicated by an
                 asterisk. The trust value is displayed with the primary  key:
                 the  first  is the assigned owner trust and the second is the
                 calculated trust value.  Letters are used for the values:

                 -         No ownertrust assigned / not yet calculated.

                 e         Trust calculation has failed; probably  due  to  an
                           expired key.

                 q         Not enough information for calculation.

                 n         Never trust this key.

                 m         Marginally trusted.

                 f         Fully trusted.

                 u         Ultimately trusted.

       --card-edit
                 Present  a  menu  to  work  with a smartcard.  The subcommand
                 "help" provides an overview on  available  commands.   For  a
                 detailed   description,   please   see   the  Card  HOWTO  at
                 http://www.gnupg.org/documentation/howtos.html#GnuPG-card-
                 HOWTO .

       --card-status
                 Show the content of the smart card.

       --change-pin
                 Present  a  menu  to  allow  changing the PIN of a smartcard.
                 This  functionality  is  also  available  as  the  subcommand
                 "passwd" with the --card-edit command.

       --sign-key name
                 Signs  a  public key with your secret key. This is a shortcut
                 version of the subcommand "sign" from --edit.

       --lsign-key name
                 Signs a public key with your secret key but marks it as  non-
                 exportable.   This  is  a  shortcut version of the subcommand
                 "lsign" from --edit.

       --delete-key name
                 Remove key from the public keyring.   In  batch  mode  either
                 --yes  is  required  or  the key must be specified by finger-
                 print.  This is a safeguard against  accidental  deletion  of
                 multiple keys.

       --delete-secret-key name
                 Remove  key from the secret and public keyring. In batch mode
                 the key must be specified by fingerprint.

       --delete-secret-and-public-key name
                 Same as --delete-key, but if a secret key exists, it will  be
                 removed  first.  In  batch  mode the key must be specified by
                 fingerprint.

       --gen-revoke name
                 Generate a revocation certificate for the  complete  key.  To
                 revoke a subkey or a signature, use the --edit command.

       --desig-revoke name
                 Generate a designated revocation certificate for a key.  This
                 allows a user (with  the  permission  of  the  keyholder)  to
                 revoke someone else's key.

       --export [names]
                 Either  export  all  keys from all keyrings (default keyrings
                 and those registered via option --keyring), or  if  at  least
                 one  name  is given, those of the given name. The new keyring
                 is written to stdout or to the file given with  option  "out-
                 put".  Use together with --armor to mail those keys.

       --send-keys [names]
                 Same  as  --export but sends the keys to a keyserver.  Option
                 --keyserver must be used to give the name of this  keyserver.
                 Don't send your complete keyring to a keyserver - select only
                 those keys which are new or changed by you.

       --export-secret-keys [names]

       --export-secret-subkeys [names]
                 Same as --export, but exports the secret keys instead.   This
                 is  normally not very useful and a security risk.  The second
                 form of the command has the special property  to  render  the
                 secret  part of the primary key useless; this is a GNU exten-
                 sion to OpenPGP and other implementations can not be expected
                 to successfully import such a key.

                 See  the  option  --simple-sk-checksum  if you want to import
                 such an exported key with an older OpenPGP implementation.

       --import [files]

       --fast-import [files]
                 Import/merge keys. This adds the given keys to  the  keyring.
                 The fast version is currently just a synonym.

                 There  are a few other options which control how this command
                 works.  Most notable here is  the  --keyserver-option  merge-
                 only  option which does not insert new keys but does only the
                 merging of new signatures, user-IDs and subkeys.

       --recv-keys key IDs
                 Import the keys with the given  key  IDs  from  a  keyserver.
                 Option --keyserver must be used to give the name of this key-
                 server.

       --refresh-keys [key IDs]
                 Request updates from a keyserver for keys that already  exist
                 on the local keyring.  This is useful for updating a key with
                 the latest signatures, user IDs, etc.  Calling this  with  no
                 arguments  will  refresh  the  entire keyring.  Option --key-
                 server must be used to give the name of the keyserver for all
                 keys  that  do  not have preferred keyservers set (see --key-
                 server-option honor-keyserver-url).

       --search-keys [names]
                 Search the keyserver for the  given  names.   Multiple  names
                 given  here  will  be  joined  together  to create the search
                 string for the keyserver.  Option --keyserver must be used to
                 give the name of this keyserver.

       --update-trustdb
                 Do  trust  database  maintenance.  This command iterates over
                 all keys and builds the Web of Trust. This is an  interactive
                 command  because it may have to ask for the "ownertrust" val-
                 ues for keys.  The user has to give an estimation of how  far
                 she  trusts  the owner of the displayed key to correctly cer-
                 tify (sign) other keys.  GnuPG only asks for  the  ownertrust
                 value  if  it  has not yet been assigned to a key.  Using the
                 --edit-key menu, the assigned value can  be  changed  at  any
                 time.

       --check-trustdb
                 Do trust database maintenance without user interaction.  From
                 time to time the trust  database  must  be  updated  so  that
                 expired  keys  or signatures and the resulting changes in the
                 Web of Trust can be tracked.  Normally, GnuPG will  calculate
                 when  this  is  required and do it automatically unless --no-
                 auto-check-trustdb is set.  This command can be used to force
                 a  trust database check at any time.  The processing is iden-
                 tical to that of --update-trustdb but it skips  keys  with  a
                 not yet defined "ownertrust".

                 For  use  with  cron  jobs, this command can be used together
                 with --batch in which case the trust database check  is  done
                 only if a check is needed.  To force a run even in batch mode
                 add the option --yes.

       --export-ownertrust
                 Send the ownertrust values to stdout.   This  is  useful  for
                 backup purposes as these values are the only ones which can't
                 be re-created from a corrupted trust DB.

       --import-ownertrust [files]
                 Update the trustdb with the ownertrust values stored in files
                 (or stdin if not given); existing values will be overwritten.

       --rebuild-keydb-caches
                 When updating from version 1.0.6 to 1.0.7 this command should
                 be  used to create signature caches in the keyring.  It might
                 be handy in other situations too.

       --print-md algo [files]

       --print-mds [files]
                 Print message digest of algorithm ALGO for all given files or
                 stdin.   With  the  second form (or a deprecated "*" as algo)
                 digests for all available algorithms are printed.

       --gen-random 0|1|2          [count]
                 Emit COUNT random bytes of the given quality level. If  count
                 is  not  given  or  zero, an endless sequence of random bytes
                 will be emitted.  PLEASE, don't use this command  unless  you
                 know  what you are doing; it may remove precious entropy from
                 the system!

       --gen-prime mode           bits            [qbits]
                 Use the source, Luke :-). The output format is still  subject
                 to change.

       --version Print  version  information  along  with  a list of supported
                 algorithms.

       --warranty
                 Print warranty information.

       -h, --help
                 Print usage information.  This is a  really  long  list  even
                 though  it  doesn't list all options.  For every option, con-
                 sult this manual.


OPTIONS

       Long   options   can   be   put   in   an   options    file    (default
       "~/.gnupg/gpg.conf").   Short option names will not work - for example,
       "armor" is a valid option for the options file, while "a" is  not.   Do
       not  write  the  2  dashes,  but  simply the name of the option and any
       required arguments.  Lines with a hash ('#') as  the  first  non-white-
       space character are ignored.  Commands may be put in this file too, but
       that is not generally useful as the command will execute  automatically
       with every execution of gpg.

       gpg recognizes these options:

       -a, --armor
                 Create ASCII armored output.

       -o, --output file
                 Write output to file.

       --max-output n
                 This  option sets a limit on the number of bytes that will be
                 generated when processing a  file.   Since  OpenPGP  supports
                 various levels of compression, it is possible that the plain-
                 text of a given message may be significantly larger than  the
                 original  OpenPGP  message.   While GnuPG works properly with
                 such messages, there is often a desire to set a maximum  file
                 size  that  will  be generated before processing is forced to
                 stop by the OS  limits.   Defaults  to  0,  which  means  "no
                 limit".

       --mangle-dos-filenames

       --no-mangle-dos-filenames
                 Older  version  of  Windows cannot handle filenames with more
                 than one dot.  --mangle-dos-filenames causes GnuPG to replace
                 (rather  than  add to) the extension of an output filename to
                 avoid this problem.  This option is off by default and has no
                 effect on non-Windows platforms.

       -u, --local-user name
                 Use  name  as  the  key  to sign with.  Note that this option
                 overrides --default-key.

       --default-key name
                 Use name as the default key to sign with.  If this option  is
                 not  used,  the  default  key  is  the first key found in the
                 secret keyring.  Note that -u or --local-user overrides  this
                 option.

       -r, --recipient name
                 Encrypt  for user id name. If this option or --hidden-recipi-
                 ent is not specified,  GnuPG  asks  for  the  user-id  unless
                 --default-recipient is given.

       -R, --hidden-recipient name
                 Encrypt  for user ID name, but hide the key ID of this user's
                 key.  This option helps to hide the receiver of  the  message
                 and is a limited countermeasure against traffic analysis.  If
                 this option or --recipient is not specified, GnuPG  asks  for
                 the user ID unless --default-recipient is given.

       --default-recipient name
                 Use  name  as  default recipient if option --recipient is not
                 used and don't ask if this is a valid one. name must be  non-
                 empty.

       --default-recipient-self
                 Use  the default key as default recipient if option --recipi-
                 ent is not used and don't ask if this is  a  valid  one.  The
                 default  key  is the first one from the secret keyring or the
                 one set with --default-key.

       --no-default-recipient
                 Reset --default-recipient and --default-recipient-self.

       --encrypt-to name
                 Same as --recipient but this one is intended for use  in  the
                 options  file  and  may  be  used with your own user-id as an
                 "encrypt-to-self".  These keys are only used when  there  are
                 other recipients given either by use of --recipient or by the
                 asked user id.  No trust checking is performed for these user
                 ids and even disabled keys can be used.

       --hidden-encrypt-to name
                 Same  as  --hidden-recipient but this one is intended for use
                 in the options file and may be used with your own user-id  as
                 a  hidden  "encrypt-to-self".   These keys are only used when
                 there are other recipients given either by use of --recipient
                 or  by the asked user id.  No trust checking is performed for
                 these user ids and even disabled keys can be used.

       --no-encrypt-to
                 Disable the use of all --encrypt-to  and  --hidden-encrypt-to
                 keys.

       -v, --verbose
                 Give  more  information during processing. If used twice, the
                 input data is listed in detail.

       -q, --quiet
                 Try to be as quiet as possible.

       -z n

       --compress-level n

       --bzip2-compress-level n
                 Set compression level to n for the ZIP and  ZLIB  compression
                 algorithms.   The  default  is to use the default compression
                 level of zlib (normally 6).  --bzip2-compress-level sets  the
                 compression   level   for  the  BZIP2  compression  algorithm
                 (defaulting to 6 as well).  This is a different  option  from
                 --compress-level  since  BZIP2  uses  a significant amount of
                 memory for each additional compression level.  -z sets  both.
                 A value of 0 for n disables compression.

       --bzip2-decompress-lowmem
                 Use  a  different  decompression  method for BZIP2 compressed
                 files.  This alternate method uses a bit more than  half  the
                 memory,  but  also  runs  at  half the speed.  This is useful
                 under extreme low memory  circumstances  when  the  file  was
                 originally compressed at a high --bzip2-compress-level.

       -t, --textmode

       --no-textmode
                 Treat  input  files  as  text  and  store them in the OpenPGP
                 canonical text form with standard "CRLF" line endings.   This
                 also  sets  the  necessary flags to inform the recipient that
                 the encrypted or signed data is text and may  need  its  line
                 endings  converted  back  to  whatever the local system uses.
                 This option is useful when communicating  between  two  plat-
                 forms  that have different line ending conventions (UNIX-like
                 to Mac, Mac to Windows, etc).   --no-textmode  disables  this
                 option, and is the default.

                 If -t (but not --textmode) is used together with armoring and
                 signing, this enables clearsigned messages.  This  kludge  is
                 needed  for command-line compatibility with command-line ver-
                 sions of PGP; normally you would use --sign or --clearsign to
                 select the type of the signature.

       -n, --dry-run
                 Don't  make any changes (this is not completely implemented).

       -i, --interactive
                 Prompt before overwriting any files.

       --batch

       --no-batch
                 Use batch mode.  Never ask, do  not  allow  interactive  com-
                 mands.  --no-batch disables this option.

       --no-tty  Make  sure that the TTY (terminal) is never used for any out-
                 put.  This option is needed in some cases because GnuPG some-
                 times prints warnings to the TTY if --batch is used.

       --yes     Assume "yes" on most questions.

       --no      Assume "no" on most questions.

       --ask-cert-level

       --no-ask-cert-level
                 When  making  a  key  signature,  prompt  for a certification
                 level.  If this option is not  specified,  the  certification
                 level  used  is set via --default-cert-level.  See --default-
                 cert-level for information on the  specific  levels  and  how
                 they  are  used.  --no-ask-cert-level  disables  this option.
                 This option defaults to no.

       --default-cert-level n
                 The default to use for the check level when signing a key.

                 0 means you make no particular claim as to how carefully  you
                 verified the key.

                 1 means you believe the key is owned by the person who claims
                 to own it but you could not, or did not  verify  the  key  at
                 all.   This is useful for a "persona" verification, where you
                 sign the key of a pseudonymous user.

                 2 means you did casual verification of the key.  For example,
                 this  could  mean  that you verified that the key fingerprint
                 and checked the user ID on the key against a photo ID.

                 3 means you did extensive verification of the key.  For exam-
                 ple,  this  could  mean that you verified the key fingerprint
                 with the owner of the key in person, and that you checked, by
                 means  of a hard to forge document with a photo ID (such as a
                 passport) that the name of the key owner matches the name  in
                 the  user  ID  on  the key, and finally that you verified (by
                 exchange of email) that the email address on the key  belongs
                 to the key owner.

                 Note  that  the  examples  given above for levels 2 and 3 are
                 just that: examples.  In the end, it is up to you  to  decide
                 just what "casual" and "extensive" mean to you.

                 This option defaults to 0 (no particular claim).

       --min-cert-level
                 When building the trust database, treat any signatures with a
                 certification level below this as invalid.   Defaults  to  2,
                 which  disregards  level 1 signatures.  Note that level 0 "no
                 particular claim" signatures are always accepted.

       --trusted-key long key ID
                 Assume that the specified key (which must be given as a  full
                 8  byte  key  ID) is as trustworthy as one of your own secret
                 keys. This option is useful if you don't want  to  keep  your
                 secret keys (or one of them) online but still want to be able
                 to check the validity of a given  recipient's  or  signator's
                 key.

       --trust-model pgp|classic|always
                 Set what trust model GnuPG should follow.  The models are:

                 pgp       This is the Web of Trust combined with trust signa-
                           tures as used in PGP 5.x and later.   This  is  the
                           default trust model.

                 classic   This  is  the  standard Web of Trust as used in PGP
                           2.x and earlier.

                 direct    Key validity is set directly by the  user  and  not
                           calculated via the Web of Trust.

                 always    Skip  key  validation and assume that used keys are
                           always fully trusted.  You won't  use  this  unless
                           you have installed some external validation scheme.
                           This option also suppresses the  "[uncertain]"  tag
                           printed with signature checks when there is no evi-
                           dence that the user ID is bound to the key.

       --always-trust
                 Identical to `--trust-model always'.  This option  is  depre-
                 cated.

       --keyid-format short|0xshort|long|0xlong
                 Select  how  to  display key IDs.  "short" is the traditional
                 8-character key ID.  "long" is the more  accurate  (but  less
                 convenient)  16-character  key  ID.  Add an "0x" to either to
                 include an "0x" at  the  beginning  of  the  key  ID,  as  in
                 0x99242560.

       --keyserver name
                 Use  name as your keyserver.  This is the server that --recv-
                 keys, --send-keys, and --search-keys will communicate with to
                 receive keys from, send keys to, and search for keys on.  The
                 format  of  the  name  is   a   URI:   `scheme:[//]keyserver-
                 name[:port]'  The  scheme is the type of keyserver: "hkp" for
                 the HTTP (or compatible) keyservers, "ldap" for the NAI  LDAP
                 keyserver,  or  "mailto" for the Graff email keyserver.  Note
                 that your particular installation of  GnuPG  may  have  other
                 keyserver  types  available  as  well.  Keyserver schemes are
                 case-insensitive.

                 Most keyservers synchronize with each other, so there is gen-
                 erally  no  need  to  send keys to more than one server.  The
                 keyserver "hkp://subkeys.pgp.net" uses  round  robin  DNS  to
                 give a different keyserver each time you use it.

       --keyserver-options parameters
                 This  is a space or comma delimited string that gives options
                 for the keyserver.  Options can be prepended with a `no-'  to
                 give  the  opposite meaning.  Valid import-options or export-
                 options may be used  here  as  well  to  apply  to  importing
                 (--recv-key)  or  exporting  (--send-key)  a  key from a key-
                 server.  While not all options are  available  for  all  key-
                 server types, some common options are:

                 include-revoked
                           When   searching  for  a  key  with  --search-keys,
                           include keys that are marked on  the  keyserver  as
                           revoked.   Note that not all keyservers differenti-
                           ate between revoked and  unrevoked  keys,  and  for
                           such  keyservers  this option is meaningless.  Note
                           also that most keyservers do not have cryptographic
                           verification  of  key  revocations,  and so turning
                           this option off may result in  skipping  keys  that
                           are incorrectly marked as revoked.  Defaults to on.

                 include-disabled
                           When  searching  for  a  key  with   --search-keys,
                           include  keys  that  are marked on the keyserver as
                           disabled.  Note that this option is not  used  with
                           HKP keyservers.

                 honor-keyserver-url
                           When  using  --refresh-keys, if the key in question
                           has a preferred keyserver set, then use  that  pre-
                           ferred keyserver to refresh the key from.  Defaults
                           to yes.

                 include-subkeys
                           When receiving a key, include subkeys as  potential
                           targets.   Note  that  this option is not used with
                           HKP keyservers, as they do not  support  retrieving
                           keys by subkey id.

                 use-temp-files
                           On  most  Unix-like  platforms,  GnuPG communicates
                           with the keyserver helper program via pipes,  which
                           is  the  most efficient method.  This option forces
                           GnuPG to use temporary files  to  communicate.   On
                           some  platforms  (such  as Win32 and RISC OS), this
                           option is always enabled.

                 keep-temp-files
                           If using `use-temp-files', do not delete  the  temp
                           files  after  using them.  This option is useful to
                           learn the keyserver communication protocol by read-
                           ing the temporary files.

                 verbose   Tell  the  keyserver helper program to be more ver-
                           bose.  This option can be repeated  multiple  times
                           to increase the verbosity level.

                 timeout   Tell the keyserver helper program how long (in sec-
                           onds) to try and perform a keyserver action  before
                           giving  up.   Note that performing multiple actions
                           at the  same  time  uses  this  timeout  value  per
                           action.  For example, when retrieving multiple keys
                           via --recv-keys, the timeout applies separately  to
                           each key retrieval, and not to the --recv-keys com-
                           mand as a whole.  Defaults to 30 seconds.

                 http-proxy[=value]
                           For HTTP-like keyserver schemes that (such  as  HKP
                           and  HTTP itself), try to access the keyserver over
                           a proxy.  If a value is specified, use this as  the
                           HTTP  proxy.   If no value is specified, try to use
                           the value of the environment variable "http_proxy".

                 auto-key-retrieve
                           This  option  enables  the  automatic retrieving of
                           keys from a  keyserver  when  verifying  signatures
                           made by keys that are not on the local keyring.

                           Note that this option makes a "web bug" like behav-
                           ior possible.  Keyserver operators  can  see  which
                           keys  you  request,  so  by  sending  you a message
                           signed by a brand new key (which you naturally will
                           not  have  on your local keyring), the operator can
                           tell both your IP address and  the  time  when  you
                           verified the signature.

       --import-options parameters
                 This  is a space or comma delimited string that gives options
                 for importing keys.  Options can be prepended with a `no-' to
                 give the opposite meaning.  The options are:

                 import-local-sigs
                           Allow  importing  key signatures marked as "local".
                           This  is  not  generally  useful  unless  a  shared
                           keyring scheme is being used.  Defaults to no.

                 repair-pks-subkey-bug
                           During  import, attempt to repair the damage caused
                           by the PKS keyserver bug (pre version  0.9.6)  that
                           mangles keys with multiple subkeys.  Note that this
                           cannot completely repair the damaged  key  as  some
                           crucial  data  is  removed by the keyserver, but it
                           does at least give you back one  subkey.   Defaults
                           to no for regular --import and to yes for keyserver
                           --recv-keys.

                 merge-only
                           During import, allow key updates to existing  keys,
                           but  do  not  allow  any  new  keys to be imported.
                           Defaults to no.

                 import-clean-sigs
                           After import, remove any signatures  from  the  new
                           key  that are not usable.  This is the same as run-
                           ning the  --edit-key  command  "clean  sigs"  after
                           import.  Defaults to no.

                 import-clean-uids
                           After  import, compact (remove all signatures from)
                           any user IDs from the new key that are not  usable.
                           This  is the same as running the --edit-key command
                           "clean uids" after import.  Defaults to no.

       --export-options parameters
                 This is a space or comma delimited string that gives  options
                 for exporting keys.  Options can be prepended with a `no-' to
                 give the opposite meaning.  The options are:

                 export-local-sigs
                           Allow exporting key signatures marked  as  "local".
                           This  is  not  generally  useful  unless  a  shared
                           keyring scheme is being used.  Defaults to no.

                 export-attributes
                           Include  attribute  user  IDs  (photo  IDs)   while
                           exporting.   This  is useful to export keys if they
                           are going to be used by  an  OpenPGP  program  that
                           does  not  accept  attribute user IDs.  Defaults to
                           yes.

                 export-sensitive-revkeys
                           Include designated  revoker  information  that  was
                           marked as "sensitive".  Defaults to no.

                 export-minimal
                           Export  the  smallest key possible.  Currently this
                           is done by leaving out any signatures that are  not
                           self-signatures.  Defaults to no.

                 export-clean-sigs
                           Do  not  export any signatures that are not usable.
                           This is the same as running the --edit-key  command
                           "clean sigs" before export.  Defaults to no.

                 export-clean-uids
                           Compact  (remove  all  signatures from) user IDs on
                           the key being exported if  the  user  IDs  are  not
                           usable.  This is the same as running the --edit-key
                           command "clean uids" before  export.   Defaults  to
                           no.

                 export-reset-subkey-passwd
                           When  using  the "--export-secret-subkeys" command,
                           this option resets the passphrases for all exported
                           subkeys to empty.  This is useful when the exported
                           subkey is to be used on an unattended amchine where
                           a passphrase won't make sense. Defaults to no.

       --list-options parameters
                 This  is a space or comma delimited string that gives options
                 used when listing keys and signatures (that is,  --list-keys,
                 --list-sigs,  --list-public-keys, --list-secret-keys, and the
                 --edit-key functions).  Options can be prepended with a `no-'
                 to give the opposite meaning.  The options are:

                 show-photos
                           Causes   --list-keys,  --list-sigs,  --list-public-
                           keys, and --list-secret-keys to display  any  photo
                           IDs attached to the key.  Defaults to no.  See also
                           --photo-viewer.

                 show-policy-urls
                           Show policy URLs in the --list-sigs or --check-sigs
                           listings.  Defaults to no.

                 show-notations

                 show-std-notations

                 show-user-notations
                           Show  all, IETF standard, or user-defined signature
                           notations in the --list-sigs or --check-sigs  list-
                           ings.  Defaults to no.

                 show-keyserver-urls
                           Show any preferred keyserver URL in the --list-sigs
                           or --check-sigs listings.  Defaults to no.

                 show-uid-validity
                           Display the calculated validity of user IDs  during
                           key listings.  Defaults to no.

                 show-unusable-uids
                           Show  revoked and expired user IDs in key listings.
                           Defaults to no.

                 show-unusable-subkeys
                           Show revoked and expired subkeys in  key  listings.
                           Defaults to no.

                 show-keyring
                           Display  the  keyring name at the head of key list-
                           ings to show which keyring a given key resides  on.
                           Defaults to no.

                 show-sig-expire
                           Show  signature  expiration  dates  (if any) during
                           --list-sigs or --check-sigs listings.  Defaults  to
                           no.

                 show-sig-subpackets
                           Include  signature  subpackets  in the key listing.
                           This option can take an optional argument  list  of
                           the  subpackets to list.  If no argument is passed,
                           list all subpackets.  Defaults to no.  This  option
                           is  only  meaningful when using --with-colons along
                           with --list-sigs or --check-sigs.

       --verify-options parameters
                 This is a space or comma delimited string that gives  options
                 used  when  verifying  signatures.   Options can be prepended
                 with a `no-' to give the opposite meaning.  The options are:

                 show-photos
                           Display any photo  IDs  present  on  the  key  that
                           issued  the  signature.   Defaults to no.  See also
                           --photo-viewer.

                 show-policy-urls
                           Show policy URLs in the signature  being  verified.
                           Defaults to no.

                 show-notations

                 show-std-notations

                 show-user-notations
                           Show  all, IETF standard, or user-defined signature
                           notations  in   the   signature   being   verified.
                           Defaults to IETF standard.

                 show-keyserver-urls
                           Show  any  preferred keyserver URL in the signature
                           being verified.  Defaults to no.

                 show-uid-validity
                           Display the calculated validity of the user IDs  on
                           the key that issued the signature.  Defaults to no.

                 show-unusable-uids
                           Show revoked and expired user IDs during  signature
                           verification.  Defaults to no.

       --show-photos

       --no-show-photos
                 Causes  --list-keys, --list-sigs, --list-public-keys, --list-
                 secret-keys, and verifying a signature to  also  display  the
                 photo  ID  attached  to  the  key, if any.  See also --photo-
                 viewer.  These options are deprecated.   Use  `--list-options
                 [no-]show-photos'  and/or `--verify-options [no-]show-photos'
                 instead.

       --photo-viewer string
                 This is the command line that should be run to view  a  photo
                 ID.   "%i"  will  be  expanded  to  a filename containing the
                 photo.  "%I" does the same,  except  the  file  will  not  be
                 deleted  once the viewer exits.  Other flags are "%k" for the
                 key ID, "%K" for the long key ID, "%f" for  the  key  finger-
                 print, "%t" for the extension of the image type (e.g. "jpg"),
                 "%T" for the MIME type of the image (e.g. "image/jpeg"),  and
                 "%%"  for  an  actual  percent sign.  If neither %i or %I are
                 present, then the photo will be supplied  to  the  viewer  on
                 standard input.

                 The  default viewer is "xloadimage -fork -quiet -title 'KeyID
                 0x%k' stdin".  Note that if your image viewer program is  not
                 secure, then executing it from GnuPG does not make it secure.

       --exec-path string
                 Sets a list of directories to search for  photo  viewers  and
                 keyserver  helpers.   If  not provided, keyserver helpers use
                 the compiled-in default directory, and photo viewers use  the
                 $PATH  environment  variable.   Note, that on W32 system this
                 value is ignored when searching for keyserver helpers.

       --show-keyring
                 Display the keyring name at the head of key listings to  show
                 which  keyring a given key resides on.  This option is depre-
                 cated: use `--list-options [no-]show-keyring' instead.

       --keyring file
                 Add file to the current list of  keyrings.   If  file  begins
                 with  a  tilde  and  a slash, these are replaced by the $HOME
                 directory. If the filename does not contain a  slash,  it  is
                 assumed  to  be  in  the  GnuPG home directory ("~/.gnupg" if
                 --homedir or $GNUPGHOME is not used).

                 Note that this adds a keyring to the current  list.   If  the
                 intent  is  to use the specified keyring alone, use --keyring
                 along with --no-default-keyring.

       --secret-keyring file
                 Same as --keyring but for the secret keyrings.

       --primary-keyring file
                 Designate file as the primary  public  keyring.   This  means
                 that  newly  imported keys (via --import or keyserver --recv-
                 from) will go to this keyring.

       --trustdb-name file
                 Use file instead of the default trustdb.  If file begins with
                 a  tilde  and a slash, these are replaced by the $HOME direc-
                 tory. If the filename does not contain a slash, it is assumed
                 to be in the GnuPG home directory ("~/.gnupg" if --homedir or
                 $GNUPGHOME is not used).

       --homedir directory
                 Set the name of the  home  directory  to  directory  If  this
                 option  is  not  used  it defaults to "~/.gnupg". It does not
                 make sense to use this in a options file. This also overrides
                 the environment variable $GNUPGHOME.

       --pcsc-driver file
                 Use file to access the smartcard reader.  The current default
                 is `libpcsclite.so'.  Instead of using this option you  might
                 also want to install a symbolic link to the default file name
                 (e.g. from `libpcsclite.so.1').

       --ctapi-driver file
                 Use file to access the smartcard reader.  The current default
                 is  `libtowitoko.so'.  Note that the use of this interface is
                 deprecated; it may be removed in future releases.

       --disable-ccid
                 Disable the integrated support for  CCID  compliant  readers.
                 This  allows to fall back to one of the other drivers even if
                 the internal CCID driver can handle the reader.   Note,  that
                 CCID  support  is  only  available if libusb was available at
                 build time.

       --reader-port number_or_string
                 This option may be used to specify the port of the card  ter-
                 minal.   A  value of 0 refers to the first serial device; add
                 32768 to access USB devices.  The default is 32768 (first USB
                 device).  PC/SC or CCID readers might need a string here; run
                 the program in verbose mode to get a list of available  read-
                 ers.  The default is then the first reader found.

       --display-charset name
                 Set  the  name  of the native character set.  This is used to
                 convert some informational  strings  like  user  IDs  to  the
                 proper  UTF-8  encoding.  If  this  option  is  not used, the
                 default character set is determined from the current  locale.
                 A  verbosity  level  of 3 shows the chosen set.  Valid values
                 for name are:

                 iso-8859-1
                           This is the Latin 1 set.

                 iso-8859-2
                           The Latin 2 set.

                 iso-8859-15
                           This is currently an alias for the Latin 1 set.

                 koi8-r    The usual Russian set (rfc1489).

                 utf-8     Bypass all translations and assume that the OS uses
                           native UTF-8 encoding.

       --utf8-strings

       --no-utf8-strings
                 Assume that command line arguments are given as UTF8 strings.
                 The default (--no-utf8-strings) is to assume  that  arguments
                 are  encoded  in the character set as specified by --display-
                 charset. These options affect all following arguments.   Both
                 options may be used multiple times.

       --options file
                 Read  options  from file and do not try to read them from the
                 default options file in the  homedir  (see  --homedir).  This
                 option is ignored if used in an options file.

       --no-options
                 Shortcut  for "--options /dev/null".  This option is detected
                 before an attempt to open an option file.  Using this  option
                 will also prevent the creation of a "~./gnupg" homedir.

       --load-extension name
                 Load an extension module. If name does not contain a slash it
                 is searched for in the directory configured  when  GnuPG  was
                 built (generally "/usr/local/lib/gnupg").  Extensions are not
                 generally useful anymore, and the use of this option is  dep-
                 recated.

       --debug flags
                 Set  debugging  flags.  All  flags are or-ed and flags may be
                 given in C syntax (e.g. 0x0042).

       --debug-all
                 Set all useful debugging flags.

       --debug-ccid-driver
                 Enable debug output from the included CCID driver for  smart-
                 cards.   Note that this option is only available on some sys-
                 tem.

       --enable-progress-filter
                 Enable certain PROGRESS status outputs.  This  option  allows
                 frontends  to  display a progress indicator while gpg is pro-
                 cessing larger files.  There is a slight performance overhead
                 using it.

       --status-fd n
                 Write  special  status strings to the file descriptor n.  See
                 the file DETAILS in the documentation for a listing of  them.

       --logger-fd n
                 Write log output to file descriptor n and not to stderr.

       --attribute-fd n
                 Write attribute subpackets to the file descriptor n.  This is
                 most useful for use with --status-fd, since the  status  mes-
                 sages  are needed to separate out the various subpackets from
                 the stream delivered to the file descriptor.

       --comment string

       --no-comments
                 Use string as a comment string in clear text  signatures  and
                 ASCII  armored  messages  or keys (see --armor).  The default
                 behavior is not to use a comment string.   --comment  may  be
                 repeated  multiple  times  to  get  multiple comment strings.
                 --no-comments removes all comments.  It is  a  good  idea  to
                 keep  the  length  of a single comment below 60 characters to
                 avoid problems with mail programs wrapping such lines.   Note
                 that comment lines, like all other header lines, are not pro-
                 tected by the signature.

       --emit-version

       --no-emit-version
                 Force inclusion of the version string in ASCII  armored  out-
                 put.  --no-emit-version disables this option.

       --sig-notation name=value

       --cert-notation name=value

       -N, --set-notation name=value
                 Put  the name value pair into the signature as notation data.
                 name must consist only of printable characters or spaces, and
                 must contain a '@' character in the form keyname@domain.exam-
                 ple.com (substituting  the  appropriate  keyname  and  domain
                 name,  of  course).  This is to help prevent pollution of the
                 IETF reserved notation namespace.  The  --expert  flag  over-
                 rides  the  '@' check.  value may be any printable string; it
                 will be encoded in UTF8, so you should check that your --dis-
                 play-charset  is  set  correctly.  If you prefix name with an
                 exclamation mark (!), the notation data will  be  flagged  as
                 critical  (rfc2440:5.2.3.15).  --sig-notation sets a notation
                 for data signatures.  --cert-notation sets a notation for key
                 signatures (certifications).  --set-notation sets both.

                 There  are  special codes that may be used in notation names.
                 "%k" will be expanded into  the  key  ID  of  the  key  being
                 signed,  "%K"  into  the long key ID of the key being signed,
                 "%f" into the fingerprint of the key being signed, "%s"  into
                 the  key  ID  of  the key making the signature, "%S" into the
                 long key ID of the key making the signature,  "%g"  into  the
                 fingerprint of the key making the signature (which might be a
                 subkey), "%p" into the fingerprint of the primary key of  the
                 key  making the signature, "%c" into the signature count from
                 the OpenPGP smartcard, and "%%" results in a single "%".  %k,
                 %K,  and  %f  are only meaningful when making a key signature
                 (certification), and %c is only  meaningful  when  using  the
                 OpenPGP smartcard.

       --show-notation

       --no-show-notation
                 Show  signature  notations in the --list-sigs or --check-sigs
                 listings as well as when verifying a signature with  a  nota-
                 tion  in  it.   These  options  are deprecated.  Use `--list-
                 options    [no-]show-notation'    and/or    `--verify-options
                 [no-]show-notation' instead.

       --sig-policy-url string

       --cert-policy-url string

       --set-policy-url string
                 Use string as a Policy URL for signatures (rfc2440:5.2.3.19).
                 If you prefix it with an exclamation mark (!), the policy URL
                 packet  will be flagged as critical.  --sig-policy-url sets a
                 policy url for data  signatures.   --cert-policy-url  sets  a
                 policy  url  for key signatures (certifications).  --set-pol-
                 icy-url sets both.

                 The same %-expandos used for notation data are available here
                 as well.

       --show-policy-url

       --no-show-policy-url
                 Show  policy URLs in the --list-sigs or --check-sigs listings
                 as well as when verifying a signature with a  policy  URL  in
                 it.   These  options  are  deprecated.   Use  `--list-options
                 [no-]show-policy-url' and/or `--verify-options [no-]show-pol-
                 icy-url' instead.

       --sig-keyserver-url string
                 Use  string as a preferred keyserver URL for data signatures.
                 If you prefix it with an exclamation mark, the keyserver  URL
                 packet will be flagged as critical.

                 The same %-expandos used for notation data are available here
                 as well.

       --set-filename string
                 Use string as the filename which is stored  inside  messages.
                 This  overrides the default, which is to use the actual file-
                 name of the file being encrypted.

       --for-your-eyes-only

       --no-for-your-eyes-only
                 Set the `for your eyes  only'  flag  in  the  message.   This
                 causes  GnuPG  to refuse to save the file unless the --output
                 option is given, and PGP to use the "secure  viewer"  with  a
                 Tempest-resistant  font  to display the message.  This option
                 overrides --set-filename.   --no-for-your-eyes-only  disables
                 this option.

       --use-embedded-filename

       --no-use-embedded-filename
                 Try  to  create  a  file with a name as embedded in the data.
                 This can be a dangerous option  as  it  allows  to  overwrite
                 files.  Defaults to no.

       --completes-needed n
                 Number  of  completely  trusted  users to introduce a new key
                 signer (defaults to 1).

       --marginals-needed n
                 Number of marginally trusted users to  introduce  a  new  key
                 signer (defaults to 3)

       --max-cert-depth n
                 Maximum depth of a certification chain (default is 5).

       --cipher-algo name
                 Use   name  as cipher algorithm. Running the program with the
                 command --version yields a list of supported  algorithms.  If
                 this  is  not  used the cipher algorithm is selected from the
                 preferences stored with the key.

       --digest-algo name
                 Use name as the message digest algorithm. Running the program
                 with  the  command --version yields a list of supported algo-
                 rithms.

       --compress-algo name
                 Use compression algorithm name.  "zlib" is RFC-1950 ZLIB com-
                 pression.  "zip" is RFC-1951 ZIP compression which is used by
                 PGP.  "bzip2" is a more modern compression  scheme  that  can
                 compress some things better than zip or zlib, but at the cost
                 of more memory used  during  compression  and  decompression.
                 "uncompressed"  or  "none"  disables  compression.   If  this
                 option is not used, the default behavior is  to  examine  the
                 recipient key preferences to see which algorithms the recipi-
                 ent supports.  If all else fails, ZIP  is  used  for  maximum
                 compatibility.

                 ZLIB  may  give  better  compression results than ZIP, as the
                 compression window size is not limited to 8k.  BZIP2 may give
                 even  better  compression  results  than that, but will use a
                 significantly larger amount of memory while  compressing  and
                 decompressing.   This may be significant in low memory situa-
                 tions.  Note, however, that PGP (all versions) only  supports
                 ZIP  compression.   Using  any  algorithm  other  than ZIP or
                 "none" will make the message unreadable with PGP.

       --cert-digest-algo name
                 Use name as the message digest algorithm used when signing  a
                 key.  Running the program with the command --version yields a
                 list of supported algorithms.  Be aware that if you choose an
                 algorithm  that  GnuPG supports but other OpenPGP implementa-
                 tions do not, then some users will not be able to use the key
                 signatures you make, or quite possibly your entire key.

       --s2k-cipher-algo name
                 Use name as the cipher algorithm used to protect secret keys.
                 The default cipher is CAST5.  This cipher is  also  used  for
                 conventional  encryption if --personal-cipher-preferences and
                 --cipher-algo is not given.

       --s2k-digest-algo name
                 Use  name  as  the  digest  algorithm  used  to  mangle   the
                 passphrases.  The default algorithm is SHA-1.

       --s2k-mode n
                 Selects  how  passphrases  are  mangled.  If  n  is 0 a plain
                 passphrase (which is not recommended) will be used, a 1  adds
                 a  salt  to the passphrase and a 3 (the default) iterates the
                 whole process a couple of times.  Unless --rfc1991  is  used,
                 this mode is also used for conventional encryption.

       --simple-sk-checksum
                 Secret  keys  are integrity protected by using a SHA-1 check-
                 sum.  This method is part of the  upcoming  enhanced  OpenPGP
                 specification  but  GnuPG already uses it as a countermeasure
                 against certain attacks.  Old applications  don't  understand
                 this new format, so this option may be used to switch back to
                 the old behaviour.  Using this option bears a security  risk.
                 Note that using this option only takes effect when the secret
                 key is encrypted - the simplest way to make this happen is to
                 change  the  passphrase  on  the key (even changing it to the
                 same value is acceptable).

       --disable-cipher-algo name
                 Never allow the use of name as cipher algorithm.   The  given
                 name  will  not  be  checked so that a later loaded algorithm
                 will still get disabled.

       --disable-pubkey-algo name
                 Never allow the use of name as  public  key  algorithm.   The
                 given  name  will not be checked so that a later loaded algo-
                 rithm will still get disabled.

       --no-sig-cache
                 Do not cache  the  verification  status  of  key  signatures.
                 Caching  gives  a  much  better  performance in key listings.
                 However, if you suspect that your public keyring is not  save
                 against  write modifications, you can use this option to dis-
                 able the caching.  It probably does not make sense to disable
                 it because all kind of damage can be done if someone else has
                 write access to your public keyring.

       --no-sig-create-check
                 GnuPG normally verifies each signature right  after  creation
                 to protect against bugs and hardware malfunctions which could
                 leak out bits from the secret key.  This  extra  verification
                 needs some time (about 115% for DSA keys), and so this option
                 can be used to disable it.  However, due to the fact that the
                 signature creation needs manual interaction, this performance
                 penalty does not matter in most settings.

       --auto-check-trustdb

       --no-auto-check-trustdb
                 If GnuPG feels that its information about the  Web  of  Trust
                 has  to be updated, it automatically runs the --check-trustdb
                 command internally.  This may be a  time  consuming  process.
                 --no-auto-check-trustdb disables this option.

       --throw-keyids

       --no-throw-keyids
                 Do  not  put  the  recipient key IDs into encrypted messages.
                 This helps to hide the receivers of the message and is a lim-
                 ited countermeasure against traffic analysis.  On the receiv-
                 ing side, it may slow down the decryption process because all
                 available  secret keys must be tried.  --no-throw-keyids dis-
                 ables this option.  This option is essentially  the  same  as
                 using --hidden-recipient for all recipients.

       --not-dash-escaped
                 This  option  changes the behavior of cleartext signatures so
                 that they can be used for patch files. You  should  not  send
                 such  an  armored  file via email because all spaces and line
                 endings are hashed too.  You can not use this option for data
                 which  has  5  dashes at the beginning of a line, patch files
                 don't have this. A special  armor  header  line  tells  GnuPG
                 about this cleartext signature option.

       --escape-from-lines

       --no-escape-from-lines
                 Because  some  mailers  change lines starting with "From " to
                 ">From " it is good to handle such lines  in  a  special  way
                 when creating cleartext signatures to prevent the mail system
                 from breaking the signature.  Note that all  other  PGP  ver-
                 sions  do it this way too.  Enabled by default.  --no-escape-
                 from-lines disables this option.

       --passphrase-fd n
                 Read the passphrase from file descriptor n. If you use 0  for
                 n,  the passphrase will be read from stdin.  This can only be
                 used if only one passphrase  is  supplied.   Don't  use  this
                 option if you can avoid it.

       --command-fd n
                 This  is  a  replacement for the deprecated shared-memory IPC
                 mode.  If this option is enabled, user input on questions  is
                 not expected from the TTY but from the given file descriptor.
                 It should be used together with  --status-fd.  See  the  file
                 doc/DETAILS  in the source distribution for details on how to
                 use it.

       --use-agent

       --no-use-agent
                 Try to use the GnuPG-Agent. Please note that  this  agent  is
                 still under development.  With this option, GnuPG first tries
                 to connect to the agent before  it  asks  for  a  passphrase.
                 --no-use-agent disables this option.

       --gpg-agent-info
                 Override    the    value    of   the   environment   variable
                 GPG_AGENT_INFO.  This is only used when --use-agent has  been
                 given

       Compliance options
                 These  options  control what GnuPG is compliant to.  Only one
                 of these options may be active at  a  time.   Note  that  the
                 default  setting  of  this  is nearly always the correct one.
                 See the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS  section
                 below before using one of these options.

                 --gnupg   Use  standard  GnuPG behavior.  This is essentially
                           OpenPGP behavior (see  --openpgp),  but  with  some
                           additional  workarounds  for  common  compatibility
                           problems in different versions of PGP.  This is the
                           default  option, so it is not generally needed, but
                           it may be useful to override a different compliance
                           option in the gpg.conf file.

                 --openpgp Reset  all  packet,  cipher  and  digest options to
                           strict OpenPGP behavior.  Use this option to  reset
                           all   previous  options  like  --rfc1991,  --force-
                           v3-sigs, --s2k-*, --cipher-algo, --digest-algo  and
                           --compress-algo  to  OpenPGP compliant values.  All
                           PGP workarounds are disabled.

                 --rfc2440 Reset all packet,  cipher  and  digest  options  to
                           strict  RFC-2440  behavior.  Note that this is cur-
                           rently the same thing as --openpgp.

                 --rfc1991 Try to be more RFC-1991 (PGP 2.x) compliant.

                 --pgp2    Set up all options to be as PGP  2.x  compliant  as
                           possible,  and  warn  if  an  action is taken (e.g.
                           encrypting to a non-RSA key)  that  will  create  a
                           message  that  PGP  2.x will not be able to handle.
                           Note that `PGP 2.x' here  means  `MIT  PGP  2.6.2'.
                           There  are other versions of PGP 2.x available, but
                           the MIT release is a good common baseline.

                           This option implies `--rfc1991 --disable-mdc  --no-
                           force-v4-certs  --no-sk-comment --escape-from-lines
                           --force-v3-sigs --no-ask-sig-expire  --no-ask-cert-
                           expire  --cipher-algo IDEA --digest-algo MD5 --com-
                           press-algo 1'.  It also  disables  --textmode  when
                           encrypting.

                 --pgp6    Set up all options to be as PGP 6 compliant as pos-
                           sible.  This restricts you to the ciphers IDEA  (if
                           the IDEA plugin is installed), 3DES, and CAST5, the
                           hashes MD5, SHA1 and RIPEMD160, and the compression
                           algorithms   none  and  ZIP.   This  also  disables
                           --throw-keyids, and making signatures with  signing
                           subkeys  as  PGP  6  does not understand signatures
                           made by signing subkeys.

                           This option implies `--disable-mdc  --no-sk-comment
                           --escape-from-lines  --force-v3-sigs  --no-ask-sig-
                           expire'

                 --pgp7    Set up all options to be as PGP 7 compliant as pos-
                           sible.   This  is  identical  to --pgp6 except that
                           MDCs are not disabled, and the  list  of  allowable
                           ciphers  is expanded to add AES128, AES192, AES256,
                           and TWOFISH.

                 --pgp8    Set up all options to be as PGP 8 compliant as pos-
                           sible.   PGP 8 is a lot closer to the OpenPGP stan-
                           dard than previous versions of  PGP,  so  all  this
                           does  is  disable  --throw-keyids and set --escape-
                           from-lines.  All algorithms are allowed except  for
                           the SHA384 and SHA512 digests.

       --force-v3-sigs

       --no-force-v3-sigs
                 OpenPGP states that an implementation should generate v4 sig-
                 natures but PGP versions 5 through 7 only recognize v4 signa-
                 tures  on key material.  This option forces v3 signatures for
                 signatures on data.  Note that this option  overrides  --ask-
                 sig-expire,  as  v3  signatures cannot have expiration dates.
                 --no-force-v3-sigs disables this option.

       --force-v4-certs

       --no-force-v4-certs
                 Always use v4 key signatures even on v3  keys.   This  option
                 also  changes the default hash algorithm for v3 RSA keys from
                 MD5 to SHA-1.  --no-force-v4-certs disables this option.

       --force-mdc
                 Force the use of encryption  with  a  modification  detection
                 code.  This is always used with the newer ciphers (those with
                 a blocksize greater than 64 bits), or if all of the recipient
                 keys indicate MDC support in their feature flags.

       --disable-mdc
                 Disable  the  use  of  the modification detection code.  Note
                 that by using this option, the encrypted message becomes vul-
                 nerable to a message modification attack.

       --allow-non-selfsigned-uid

       --no-allow-non-selfsigned-uid
                 Allow  the import and use of keys with user IDs which are not
                 self-signed.  This is not recommended, as a  non  self-signed
                 user  ID  is trivial to forge.  --no-allow-non-selfsigned-uid
                 disables.

       --allow-freeform-uid
                 Disable all checks on the form of the user ID while  generat-
                 ing  a new one.  This option should only be used in very spe-
                 cial environments as it does not ensure the de-facto standard
                 format of user IDs.

       --ignore-time-conflict
                 GnuPG  normally  checks  that  the timestamps associated with
                 keys and signatures have plausible  values.   However,  some-
                 times a signature seems to be older than the key due to clock
                 problems.  This option makes these  checks  just  a  warning.
                 See also --ignore-valid-from for timestamp issues on subkeys.

       --ignore-valid-from
                 GnuPG normally does not select and use subkeys created in the
                 future.   This  option  allows  the use of such keys and thus
                 exhibits the pre-1.0.7 behaviour.  You should  not  use  this
                 option  unless  you  there  is  some clock problem.  See also
                 --ignore-time-conflict for timestamp issues with  signatures.

       --ignore-crc-error
                 The  ASCII armor used by OpenPGP is protected by a CRC check-
                 sum against transmission errors.  Occasionally the  CRC  gets
                 mangled  somewhere on the transmission channel but the actual
                 content (which is protected by the OpenPGP  protocol  anyway)
                 is  still  okay.   This  option  allows  GnuPG  to ignore CRC
                 errors.

       --ignore-mdc-error
                 This option changes a MDC integrity protection failure into a
                 warning.   This  can be useful if a message is partially cor-
                 rupt, but it is necessary to get as much data as possible out
                 of the corrupt message.  However, be aware that a MDC protec-
                 tion failure may also mean that the message was tampered with
                 intentionally by an attacker.

       --lock-once
                 Lock  the databases the first time a lock is requested and do
                 not release the lock until the process terminates.

       --lock-multiple
                 Release the locks every time a lock is no longer needed.  Use
                 this to override a previous --lock-once from a config file.

       --lock-never
                 Disable locking entirely.  This option should be used only in
                 very special environments, where it can be assured that  only
                 one process is accessing those files.  A bootable floppy with
                 a stand-alone  encryption  system  will  probably  use  this.
                 Improper  usage  of this option may lead to data and key cor-
                 ruption.

       --exit-on-status-write-error
                 This option will cause write errors on the status FD to imme-
                 diately  terminate  the  process.  That should in fact be the
                 default but it never worked this way  and  thus  we  need  an
                 option  to enable this, so that the change won't break appli-
                 cations which close their end of a status fd  connected  pipe
                 too  early.   Using this option along with --enable-progress-
                 filter may be used to cleanly cancel long running gpg  opera-
                 tions.

       --limit-card-insert-tries n
                 With  n greater than 0 the number of prompts asking to insert
                 a smartcard gets limited to N-1.  Thus with a value of 1  gpg
                 won't  at  all ask to insert a card if none has been inserted
                 at startup. This option is useful in the  configuration  file
                 in case an application does not know about the smartcard sup-
                 port and waits ad infinitum for an inserted card.

       --no-random-seed-file
                 GnuPG uses a file to store  its  internal  random  pool  over
                 invocations.   This  makes  random generation faster; however
                 sometimes write operations are not desired.  This option  can
                 be used to achieve that with the cost of slower random gener-
                 ation.

       --no-verbose
                 Reset verbose level to 0.

       --no-greeting
                 Suppress the initial copyright message.

       --no-secmem-warning
                 Suppress the warning about "using insecure memory".

       --no-permission-warning
                 Suppress the warning about unsafe  file  and  home  directory
                 (--homedir)  permissions.   Note  that  the permission checks
                 that GnuPG performs are not intended to be authoritative, but
                 rather they simply warn about certain common permission prob-
                 lems.  Do not assume that the lack of a  warning  means  that
                 your system is secure.

                 Note that the warning for unsafe --homedir permissions cannot
                 be supressed in the gpg.conf file, as  this  would  allow  an
                 attacker  to  place an unsafe gpg.conf file in place, and use
                 this file to supress warnings about  itself.   The  --homedir
                 permissions  warning  may  only  be  supressed on the command
                 line.

       --no-mdc-warning
                 Suppress the warning about missing MDC integrity  protection.

       --require-secmem

       --no-require-secmem
                 Refuse to run if GnuPG cannot get secure memory.  Defaults to
                 no (i.e. run, but give a warning).

       --no-armor
                 Assume the input data is not in ASCII armored format.

       --no-default-keyring
                 Do not add the default keyrings  to  the  list  of  keyrings.
                 Note  that GnuPG will not operate without any keyrings, so if
                 you use this option and do not provide alternate keyrings via
                 --keyring  or --secret-keyring, then GnuPG will still use the
                 default public or secret keyrings.

       --skip-verify
                 Skip the signature verification step.  This may  be  used  to
                 make  the  decryption faster if the signature verification is
                 not needed.

       --with-colons
                 Print key listings delimited by colons.  Note that the output
                 will  be encoded in UTF-8 regardless of any --display-charset
                 setting.  This format is useful when  GnuPG  is  called  from
                 scripts  and  other  programs as it is easily machine parsed.
                 The details  of  this  format  are  documented  in  the  file
                 doc/DETAILS,  which is included in the GnuPG source distribu-
                 tion.

       --with-key-data
                 Print key listings delimited by colons  (like  --with-colons)
                 and print the public key data.

       --with-fingerprint
                 Same as the command --fingerprint but changes only the format
                 of the output and may be used together with another  command.

       --fast-list-mode
                 Changes  the output of the list commands to work faster; this
                 is achieved by leaving some parts empty.   Some  applications
                 don't need the user ID and the trust information given in the
                 listings.  By using this options they can get a faster  list-
                 ing.  The exact behaviour of this option may change in future
                 versions.

       --fixed-list-mode
                 Do not merge primary user ID and primary key in  --with-colon
                 listing  mode  and  print  all  timestamps  as  seconds since
                 1970-01-01.

       --list-only
                 Changes the behaviour of some commands.  This is like  --dry-
                 run  but  different in some cases.  The semantic of this com-
                 mand may be extended in the future.  Currently it only  skips
                 the actual decryption pass and therefore enables a fast list-
                 ing of the encryption keys.

       --no-literal
                 This is not for normal use.  Use the source to see  for  what
                 it might be useful.

       --set-filesize
                 This  is  not for normal use.  Use the source to see for what
                 it might be useful.

       --show-session-key
                 Display the session key used for one message. See --override-
                 session-key for the counterpart of this option.

                 We  think  that  Key  Escrow is a Bad Thing; however the user
                 should have the freedom to decide whether to go to prison  or
                 to reveal the content of one specific message without compro-
                 mising all messages ever encrypted for one secret key.  DON'T
                 USE IT UNLESS YOU ARE REALLY FORCED TO DO SO.

       --override-session-key string
                 Don't  use  the  public  key but the session key string.  The
                 format of this string is the  same  as  the  one  printed  by
                 --show-session-key.   This  option  is  normally not used but
                 comes handy in case someone forces you to reveal the  content
                 of  an  encrypted  message; using this option you can do this
                 without handing out the secret key.

       --ask-sig-expire

       --no-ask-sig-expire
                 When making a data signature, prompt for an expiration  time.
                 If  this option is not specified, the expiration time set via
                 --default-sig-expire is used.   --no-ask-sig-expire  disables
                 this option.

       --default-sig-expire
                 The  default expiration time to use for signature expiration.
                 Valid values are "0" for no expiration, a number followed  by
                 the  letter d (for days), w (for weeks), m (for months), or y
                 (for years) (for example "2m" for two  months,  or  "5y"  for
                 five  years),  or  an  absolute  date in the form YYYY-MM-DD.
                 Defaults to "0".

       --ask-cert-expire

       --no-ask-cert-expire
                 When making a key signature, prompt for an  expiration  time.
                 If  this option is not specified, the expiration time set via
                 --default-cert-expire is used.  --no-ask-cert-expire disables
                 this option.

       --default-cert-expire
                 The  default expiration time to use for key signature expira-
                 tion.  Valid values are "0" for no expiration, a number  fol-
                 lowed  by  the  letter  d  (for  days), w (for weeks), m (for
                 months), or y (for years) (for example "2m" for  two  months,
                 or  "5y"  for  five  years),  or an absolute date in the form
                 YYYY-MM-DD.  Defaults to "0".

       --expert

       --no-expert
                 Allow the user to do certain nonsensical  or  "silly"  things
                 like  signing  an  expired  or revoked key, or certain poten-
                 tially incompatible things like generating unusual key types.
                 This also disables certain warning messages about potentially
                 incompatible actions.  As the name implies,  this  option  is
                 for experts only.  If you don't fully understand the implica-
                 tions of what it allows you to do,  leave  this  off.   --no-
                 expert disables this option.

       --allow-secret-key-import
                 This is an obsolete option and is not used anywhere.

       --try-all-secrets
                 Don't look at the key ID as stored in the message but try all
                 secret keys in turn to find the right  decryption  key.  This
                 option  forces  the behaviour as used by anonymous recipients
                 (created by using --throw-keyids) and  might  come  handy  in
                 case where an encrypted message contains a bogus key ID.

       --enable-special-filenames
                 This  options  enables  a mode in which filenames of the form
                 -&n, where n is a non-negative decimal number, refer  to  the
                 file descriptor n and not to a file with that name.

       --no-expensive-trust-checks
                 Experimental use only.

       --group name=value1 [value2 value3 ...]
                 Sets  up  a named group, which is similar to aliases in email
                 programs.  Any time the group name  is  a  recipient  (-r  or
                 --recipient),  it  will  be expanded to the values specified.
                 Multiple groups with the same name are  automatically  merged
                 into a single group.

                 The  values are key IDs or fingerprints, but any key descrip-
                 tion is accepted.  Note that a value with spaces in  it  will
                 be  treated as two different values.  Note also there is only
                 one level of expansion - you cannot make an group that points
                 to another group.  When used from the command line, it may be
                 necessary to quote the argument to this option to prevent the
                 shell from treating it as multiple arguments.

       --ungroup name
                 Remove a given entry from the --group list.

       --no-groups
                 Remove all entries from the --group list.

       --preserve-permissions
                 Don't change the permissions of a secret keyring back to user
                 read/write only.  Use this option only  if  you  really  know
                 what you are doing.

       --personal-cipher-preferences string
                 Set  the  list of personal cipher preferences to string, this
                 list should be a string similar to the  one  printed  by  the
                 command  "pref"  in  the  edit menu.  This allows the user to
                 factor in their own preferred algorithms when algorithms  are
                 chosen via recipient key preferences.  The most highly ranked
                 cipher in this list is also used for the --symmetric  encryp-
                 tion command.

       --personal-digest-preferences string
                 Set  the  list of personal digest preferences to string, this
                 list should be a string similar to the  one  printed  by  the
                 command  "pref"  in  the  edit menu.  This allows the user to
                 factor in their own preferred algorithms when algorithms  are
                 chosen via recipient key preferences.  The most highly ranked
                 digest algorithm in this list is algo used when signing with-
                 out  encryption  (e.g.  --clearsign  or --sign).  The default
                 value is SHA-1.

       --personal-compress-preferences string
                 Set the list of personal compression preferences  to  string,
                 this  list  should  be a string similar to the one printed by
                 the command "pref" in the edit menu.  This allows the user to
                 factor  in their own preferred algorithms when algorithms are
                 chosen via recipient key preferences.  The most highly ranked
                 algorithm in this list is also used when there are no recipi-
                 ent keys to consider (e.g. --symmetric).

       --default-preference-list string
                 Set the list of default  preferences  to  string,  this  list
                 should  be a string similar to the one printed by the command
                 "pref" in the edit menu.  This affects  both  key  generation
                 and "updpref" in the edit menu.

       --list-config [names]
                 Display  various  internal configuration parameters of GnuPG.
                 This option is intended for external programs that call GnuPG
                 to  perform tasks, and is thus not generally useful.  See the
                 file doc/DETAILS in the source distribution for  the  details
                 of which configuration items may be listed.  --list-config is
                 only usable with --with-colons set.


How to specify a user ID

       There are different ways to specify a user ID to GnuPG; here  are  some
       examples:

       234567C4

       0F34E556E

       01347A56A

       0xAB123456
                 Here the key ID is given in the usual short form.

       234AABBCC34567C4

       0F323456784E56EAB

       01AB3FED1347A5612

       0x234AABBCC34567C4
                 Here  the key ID is given in the long form as used by OpenPGP
                 (you can get the long key ID using the option --with-colons).

       1234343434343434C434343434343434

       123434343434343C3434343434343734349A3434

       0E12343434343434343434EAB3484343434343434

       0xE12343434343434343434EAB3484343434343434
                 The  best way to specify a key ID is by using the fingerprint
                 of the key.  This avoids any ambiguities in case  that  there
                 are  duplicated  key  IDs (which are really rare for the long
                 key IDs).

       =Heinrich Heine <heinrichh@uni-duesseldorf.de>
                 Using an exact to match string.   The  equal  sign  indicates
                 this.

       <heinrichh@uni-duesseldorf.de>
                 Using  the  email  address part which must match exactly. The
                 left angle bracket indicates this email address mode.

       +Heinrich Heine duesseldorf
                 All words must match exactly (not  case  sensitive)  but  can
                 appear  in any order in the user ID.  Words are any sequences
                 of letters, digits, the underscore and  all  characters  with
                 bit 7 set.

       Heine

       *Heine    By  case insensitive substring matching.  This is the default
                 mode but applications may want to explicitly indicate this by
                 putting the asterisk in front.

       Note  that you can append an exclamation mark (!) to key IDs or finger-
       prints.  This flag tells GnuPG to use the  specified  primary  or  sec-
       ondary  key and not to try and calculate which primary or secondary key
       to use.


RETURN VALUE

       The program returns 0 if everything was fine, 1 if at least a signature
       was bad, and other error codes for fatal errors.


EXAMPLES

       gpg -se -r Bob file
                 sign and encrypt for user Bob

       gpg --clearsign file
                 make a clear text signature

       gpg -sb  file
                 make a detached signature

       gpg --list-keys  user_ID
                 show keys

       gpg --fingerprint  user_ID
                 show fingerprint

       gpg --verify  pgpfile

       gpg --verify  sigfile [files]
                 Verify  the signature of the file but do not output the data.
                 The second form is used for detached signatures,  where  sig-
                 file  is  the  detached  signature  (either  ASCII armored or
                 binary) and [files] are the  signed  data;  if  this  is  not
                 given,  the  name of the file holding the signed data is con-
                 structed by cutting off the extension (".asc" or  ".sig")  of
                 sigfile or by asking the user for the filename.


ENVIRONMENT

       HOME      Used to locate the default home directory.

       GNUPGHOME If set directory used instead of "~/.gnupg".

       GPG_AGENT_INFO
                 Used  to  locate the gpg-agent; only honored when --use-agent
                 is set.  The value consists of 3 colon delimited fields:  The
                 first  is  the path to the Unix Domain Socket, the second the
                 PID of the gpg-agent and the protocol version which should be
                 set  to  1.   When starting the gpg-agent as described in its
                 documentation, this variable is set  to  the  correct  value.
                 The option --gpg-agent-info can be used to override it.

       http_proxy
                 Only  honored  when  the keyserver-option honor-http-proxy is
                 set.

       COLUMNS

       LINES     Used to size some displays to the full size of the screen.


FILES

       ~/.gnupg/secring.gpg
                 The secret keyring

       ~/.gnupg/secring.gpg.lock
                 and the lock file

       ~/.gnupg/pubring.gpg
                 The public keyring

       ~/.gnupg/pubring.gpg.lock
                 and the lock file

       ~/.gnupg/trustdb.gpg
                 The trust database

       ~/.gnupg/trustdb.gpg.lock
                 and the lock file

       ~/.gnupg/random_seed
                 used to preserve the internal random pool

       ~/.gnupg/gpg.conf
                 Default configuration file

       ~/.gnupg/options
                 Old style configuration file; only used when gpg.conf is  not
                 found

       /usr[/local]/share/gnupg/options.skel
                 Skeleton options file

       /usr[/local]/lib/gnupg/
                 Default location for extensions


WARNINGS

       Use  a *good* password for your user account and a *good* passphrase to
       protect your secret key.  This passphrase is the weakest  part  of  the
       whole system.  Programs to do dictionary attacks on your secret keyring
       are very easy to write and  so  you  should  protect  your  "~/.gnupg/"
       directory very well.

       Keep  in mind that, if this program is used over a network (telnet), it
       is *very* easy to spy out your passphrase!

       If you are going to verify detached signatures, make sure that the pro-
       gram  knows about it; either give both filenames on the command line or
       use - to specify stdin.


INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS

       GnuPG tries to be a very flexible implementation of the  OpenPGP  stan-
       dard.   In  particular,  GnuPG implements many of the optional parts of
       the standard, such as the SHA-512 hash, and the ZLIB and BZIP2 compres-
       sion algorithms.  It is important to be aware that not all OpenPGP pro-
       grams implement these optional algorithms and that by forcing their use
       via  the  --cipher-algo,  --digest-algo,  --cert-digest-algo, or --com-
       press-algo options in GnuPG, it is possible to create a perfectly valid
       OpenPGP message, but one that cannot be read by the intended recipient.

       There are dozens of variations of OpenPGP programs available, and  each
       supports a slightly different subset of these optional algorithms.  For
       example, until recently, no (unhacked) version  of  PGP  supported  the
       BLOWFISH  cipher  algorithm.  A message using BLOWFISH simply could not
       be read by a PGP user.  By default, GnuPG  uses  the  standard  OpenPGP
       preferences  system that will always do the right thing and create mes-
       sages that are usable by all recipients, regardless  of  which  OpenPGP
       program  they  use.  Only override this safe default if you really know
       what you are doing.

       If you absolutely must override the safe default, or if the preferences
       on  a  given  key  are  invalid for some reason, you are far better off
       using the --pgp6, --pgp7, or --pgp8 options.  These options are safe as
       they  do  not  force any particular algorithms in violation of OpenPGP,
       but rather reduce the available algorithms to a "PGP-safe" list.


BUGS

       On many systems this program should be installed as setuid(root).  This
       is  necessary  to lock memory pages.  Locking memory pages prevents the
       operating  system  from  writing  memory  pages  (which   may   contain
       passphrases  or other sensitive material) to disk.  If you get no warn-
       ing message about insecure memory your operating system supports  lock-
       ing  without  being root.  The program drops root privileges as soon as
       locked memory is allocated.

                                                                        gpg(1)

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