1=pod 2 3=head1 NAME 4 5DSA_sign, DSA_sign_setup, DSA_verify - DSA signatures 6 7=head1 SYNOPSIS 8 9 #include <openssl/dsa.h> 10 11 int DSA_sign(int type, const unsigned char *dgst, int len, 12 unsigned char *sigret, unsigned int *siglen, DSA *dsa); 13 14 int DSA_sign_setup(DSA *dsa, BN_CTX *ctx, BIGNUM **kinvp, BIGNUM **rp); 15 16 int DSA_verify(int type, const unsigned char *dgst, int len, 17 unsigned char *sigbuf, int siglen, DSA *dsa); 18 19=head1 DESCRIPTION 20 21DSA_sign() computes a digital signature on the B<len> byte message 22digest B<dgst> using the private key B<dsa> and places its ASN.1 DER 23encoding at B<sigret>. The length of the signature is places in 24*B<siglen>. B<sigret> must point to DSA_size(B<dsa>) bytes of memory. 25 26DSA_sign_setup() is defined only for backward binary compatibility and 27should not be used. 28Since OpenSSL 1.1.0 the DSA type is opaque and the output of 29DSA_sign_setup() cannot be used anyway: calling this function will only 30cause overhead, and does not affect the actual signature 31(pre-)computation. 32 33DSA_verify() verifies that the signature B<sigbuf> of size B<siglen> 34matches a given message digest B<dgst> of size B<len>. 35B<dsa> is the signer's public key. 36 37The B<type> parameter is ignored. 38 39The PRNG must be seeded before DSA_sign() (or DSA_sign_setup()) 40is called. 41 42=head1 RETURN VALUES 43 44DSA_sign() and DSA_sign_setup() return 1 on success, 0 on error. 45DSA_verify() returns 1 for a valid signature, 0 for an incorrect 46signature and -1 on error. The error codes can be obtained by 47L<ERR_get_error(3)>. 48 49=head1 CONFORMING TO 50 51US Federal Information Processing Standard FIPS 186 (Digital Signature 52Standard, DSS), ANSI X9.30 53 54=head1 SEE ALSO 55 56L<DSA_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, 57L<DSA_do_sign(3)> 58 59=head1 COPYRIGHT 60 61Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved. 62 63Licensed under the OpenSSL license (the "License"). You may not use 64this file except in compliance with the License. You can obtain a copy 65in the file LICENSE in the source distribution or at 66L<https://www.openssl.org/source/license.html>. 67 68=cut 69