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

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

DSA_sign_setup(3) may be used to precompute part of the signing operation in case signature generation is time-critical.

DSA_do_verify() verifies that the signature sig matches a given message digest dgst of size dgst_len. dsa is the signer's public key.

RETURN VALUES

DSA_do_sign() returns the signature or NULL on error. DSA_do_verify() returns 1 for a valid signature, 0 for an incorrect signature, and -1 on error. The error codes can be obtained by ERR_get_error(3).

SEE ALSO

DSA_get0_key(3), DSA_meth_set_sign(3), DSA_new(3), DSA_SIG_new(3), DSA_sign(3)

HISTORY

DSA_do_sign() and DSA_do_verify() first appeared in OpenSSL 0.9.3 and have been available since OpenBSD 2.6.