| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | =pod |
| 2 | |
| 3 | =head1 NAME |
| 4 | |
| 5 | DSA_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 | |
| 21 | DSA_sign() computes a digital signature on the B<len> byte message |
| 22 | digest B<dgst> using the private key B<dsa> and places its ASN.1 DER |
| 23 | encoding 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 | |
| 26 | DSA_sign_setup() is defined only for backward binary compatibility and |
| 27 | should not be used. |
| 28 | Since OpenSSL 1.1.0 the DSA type is opaque and the output of |
| 29 | DSA_sign_setup() cannot be used anyway: calling this function will only |
| 30 | cause overhead, and does not affect the actual signature |
| 31 | (pre-)computation. |
| 32 | |
| 33 | DSA_verify() verifies that the signature B<sigbuf> of size B<siglen> |
| 34 | matches a given message digest B<dgst> of size B<len>. |
| 35 | B<dsa> is the signer's public key. |
| 36 | |
| 37 | The B<type> parameter is ignored. |
| 38 | |
| 39 | The random generator must be seeded when DSA_sign() (or DSA_sign_setup()) |
| 40 | is called. |
| 41 | If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to |
| 42 | external circumstances (see L<RAND(7)>), the operation will fail. |
| 43 | |
| 44 | =head1 RETURN VALUES |
| 45 | |
| 46 | DSA_sign() and DSA_sign_setup() return 1 on success, 0 on error. |
| 47 | DSA_verify() returns 1 for a valid signature, 0 for an incorrect |
| 48 | signature and -1 on error. The error codes can be obtained by |
| 49 | L<ERR_get_error(3)>. |
| 50 | |
| 51 | =head1 CONFORMING TO |
| 52 | |
| 53 | US Federal Information Processing Standard FIPS 186 (Digital Signature |
| 54 | Standard, DSS), ANSI X9.30 |
| 55 | |
| 56 | =head1 SEE ALSO |
| 57 | |
| 58 | L<DSA_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, |
| 59 | L<DSA_do_sign(3)>, |
| 60 | L<RAND(7)> |
| 61 | |
| 62 | =head1 COPYRIGHT |
| 63 | |
| 64 | Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved. |
| 65 | |
| 66 | Licensed under the OpenSSL license (the "License"). You may not use |
| 67 | this file except in compliance with the License. You can obtain a copy |
| 68 | in the file LICENSE in the source distribution or at |
| 69 | L<https://www.openssl.org/source/license.html>. |
| 70 | |
| 71 | =cut |