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), ERR_get_error(3), RAND_bytes(3)
HISTORY
DSA_do_sign() and
DSA_do_verify() first appeared in OpenSSL 0.9.3 and
have been available since OpenBSD 2.6.