/usr/man2/cat.3/RSA_sign.3.Z(/usr/man2/cat.3/RSA_sign.3.Z)

NAME

       RSA_sign, RSA_verify - RSA signatures

SYNOPSIS

        #include <openssl/rsa.h>

        int RSA_sign(int type, const unsigned char *m, unsigned int m_len,
           unsigned char *sigret, unsigned int *siglen, RSA *rsa);

        int RSA_verify(int type, const unsigned char *m, unsigned int m_len,
           unsigned char *sigbuf, unsigned int siglen, RSA *rsa);

DESCRIPTION

       RSA_sign() signs the message digest m of size m_len using the private
       key rsa as specified in PKCS #1 v2.0. It stores the signature in sigret
       and the signature size in siglen. sigret must point to RSA_size(rsa)
       bytes of memory.  Note that PKCS #1 adds meta-data, placing limits on
       the size of the key that can be used.  See RSA_private_encrypt(3) for
       lower-level operations.

       type denotes the message digest algorithm that was used to generate m.
       It usually is one of NID_sha1, NID_ripemd160 and NID_md5; see
       objects(3) for details. If type is NID_md5_sha1, an SSL signature (MD5
       and SHA1 message digests with PKCS #1 padding and no algorithm identi-
       fier) is created.

       RSA_verify() verifies that the signature sigbuf of size siglen matches
       a given message digest m of size m_len. type denotes the message digest
       algorithm that was used to generate the signature.  rsa is the signer's
       public key.

RETURN VALUES

       RSA_sign() returns 1 on success, 0 otherwise.  RSA_verify() returns 1
       on successful verification, 0 otherwise.

       The error codes can be obtained by ERR_get_error(3).

BUGS

       Certain signatures with an improper algorithm identifier are accepted
       for compatibility with SSLeay 0.4.5 :-)

CONFORMING TO

       SSL, PKCS #1 v2.0

SEE ALSO

       ERR_get_error(3), objects(3), rsa(3), RSA_private_encrypt(3), RSA_pub-
       lic_decrypt(3)

HISTORY

       RSA_sign() and RSA_verify() are available in all versions of SSLeay and
       OpenSSL.

1.0.2t                            2019-09-10                       RSA_sign(3)
See also RSA_verify(3)