DSA_do_sign.pod revision 337982 
1=pod
2
3=head1 NAME
4
5DSA_do_sign, DSA_do_verify - raw DSA signature operations
6
7=head1 SYNOPSIS
8
9 #include <openssl/dsa.h>
10
11 DSA_SIG *DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);
12
13 int DSA_do_verify(const unsigned char *dgst, int dgst_len,
14	     DSA_SIG *sig, DSA *dsa);
15
16=head1 DESCRIPTION
17
18DSA_do_sign() computes a digital signature on the B<len> byte message
19digest B<dgst> using the private key B<dsa> and returns it in a
20newly allocated B<DSA_SIG> structure.
21
22L<DSA_sign_setup(3)|DSA_sign_setup(3)> may be used to precompute part
23of the signing operation for each signature in case signature generation
24is time-critical.
25
26DSA_do_verify() verifies that the signature B<sig> matches a given
27message digest B<dgst> of size B<len>.  B<dsa> is the signer's public
28key.
29
30=head1 RETURN VALUES
31
32DSA_do_sign() returns the signature, NULL on error.  DSA_do_verify()
33returns 1 for a valid signature, 0 for an incorrect signature and -1
34on error. The error codes can be obtained by
35L<ERR_get_error(3)|ERR_get_error(3)>.
36
37=head1 SEE ALSO
38
39L<dsa(3)|dsa(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<rand(3)|rand(3)>,
40L<DSA_SIG_new(3)|DSA_SIG_new(3)>,
41L<DSA_sign(3)|DSA_sign(3)>
42
43=head1 HISTORY
44
45DSA_do_sign() and DSA_do_verify() were added in OpenSSL 0.9.3.
46
47=cut
48