RSA_sign 3 2005-11-24 0.9.9-dev OpenSSL

### NAME

RSA_sign, RSA_verify - RSA signatures

### LIBRARY

libcrypto, -lcrypto

### SYNOPSIS

     #include

     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.

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 identifier) 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), openssl_rsa(3), RSA_private_encrypt(3), RSA_public_decrypt(3)

### HISTORY

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