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 mes-
sage 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 sign-
ing 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_get_error(3), rand(3), DSA_do_sign(3)MirOS BSD #10-current 2005-02-05 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.
MirOS BSD #10-current 2005-02-05 2
