DSA_sign(3) OpenSSL DSA_sign(3)NAME
DSA_sign, DSA_sign_setup, DSA_verify - DSA signatures
SYNOPSIS
#include <openssl/dsa.h>
int DSA_sign(int type, const unsigned char *dgst, int len,
unsigned char *sigret, unsigned int *siglen, DSA *dsa);
int DSA_sign_setup(DSA *dsa, BN_CTX *ctx, BIGNUM **kinvp,
BIGNUM **rp);
int DSA_verify(int type, const unsigned char *dgst, int len,
unsigned char *sigbuf, int siglen, DSA *dsa);
DESCRIPTIONDSA_sign() computes a digital signature on the len byte
message digest dgst using the private key dsa and places
its ASN.1 DER encoding at sigret. The length of the
signature is places in *siglen. sigret must point to
DSA_size(dsa) bytes of memory.
DSA_sign_setup() may be used to precompute part of the
signing operation in case signature generation is time-
critical. It expects dsa to contain DSA parameters. It
places the precomputed values in newly allocated BIGNUMs
at *kinvp and *rp, after freeing the old ones unless
*kinvp and *rp are NULL. These values may be passed to
DSA_sign() in dsa->kinv and dsa->r. ctx is a pre-
allocated BN_CTX or NULL.
DSA_verify() verifies that the signature sigbuf of size
siglen matches a given message digest dgst of size len.
dsa is the signer's public key.
The type parameter is ignored.
The PRNG must be seeded before DSA_sign() (or
DSA_sign_setup()) is called.
RETURN VALUESDSA_sign() and DSA_sign_setup() return 1 on success, 0 on
error. DSA_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).
CONFORMING TO
US Federal Information Processing Standard FIPS 186
(Digital Signature Standard, DSS), ANSI X9.30
SEE ALSOdsa(3), err(3), rand(3), DSA_do_sign(3)16/Aug/2000 0.9.6 1
DSA_sign(3) OpenSSL DSA_sign(3)HISTORYDSA_sign() and DSA_verify() are available in all versions
of SSLeay. DSA_sign_setup() was added in SSLeay 0.8.
16/Aug/2000 0.9.6 2
