NAME

DSA_do_sign, DSA_do_verify − Raw DSA signature operations

SYNOPSIS

#include <openssl/dsa.h>
DSA_SIG ∗DSA_do_sign(
        const unsigned char ∗dgst, int dlen, DSA ∗dsa ); int DSA_do_verify(
        const unsigned char ∗dgst, int dgst_len, DSA_SIG ∗sig, DSA ∗dsa );

DESCRIPTION

The DSA_do_sign() function computes a digital signature on the len byte message digest dgst using the private key dsa and returns it in a newly allocated DSA_SIG structure. 

The DSA_sign_setup() function can be used to precompute part of the signing operation in case signature generation is time-critical. 

The DSA_do_verify() function verifies that the signature sig matches a given message digest dgst of size len.  The dsa is the signer’s public key. 

RETURN VALUES

The DSA_do_sign() function returns the signature, NULL on error.  The DSA_do_verify() function returns 1 for a valid signature, 0 for an incorrect signature and -1 on error. The error codes can be obtained from ERR_get_error(). 

HISTORY

The DSA_do_sign() and DSA_do_verify() functions were added in OpenSSL 0.9.3. 

SEE ALSO

Functions: dsa(3), err(3), rand(3), DSA_SIG_new(3), DSA_sign(3)