RSA_sign.pod revision 279265 
1=pod
2
3=head1 NAME
4
5RSA_sign, RSA_verify - RSA signatures
6
7=head1 SYNOPSIS
8
9 #include <openssl/rsa.h>
10
11 int RSA_sign(int type, const unsigned char *m, unsigned int m_len,
12    unsigned char *sigret, unsigned int *siglen, RSA *rsa);
13
14 int RSA_verify(int type, const unsigned char *m, unsigned int m_len,
15    unsigned char *sigbuf, unsigned int siglen, RSA *rsa);
16
17=head1 DESCRIPTION
18
19RSA_sign() signs the message digest B<m> of size B<m_len> using the
20private key B<rsa> as specified in PKCS #1 v2.0. It stores the
21signature in B<sigret> and the signature size in B<siglen>. B<sigret>
22must point to RSA_size(B<rsa>) bytes of memory.
23Note that PKCS #1 adds meta-data, placing limits on the size of the
24key that can be used.
25See L<RSA_private_encrypt(3)|RSA_private_encrypt(3)> for lower-level
26operations.
27
28B<type> denotes the message digest algorithm that was used to generate
29B<m>. It usually is one of B<NID_sha1>, B<NID_ripemd160> and B<NID_md5>;
30see L<objects(3)|objects(3)> for details. If B<type> is B<NID_md5_sha1>,
31an SSL signature (MD5 and SHA1 message digests with PKCS #1 padding
32and no algorithm identifier) is created.
33
34RSA_verify() verifies that the signature B<sigbuf> of size B<siglen>
35matches a given message digest B<m> of size B<m_len>. B<type> denotes
36the message digest algorithm that was used to generate the signature.
37B<rsa> is the signer's public key.
38
39=head1 RETURN VALUES
40
41RSA_sign() returns 1 on success, 0 otherwise.  RSA_verify() returns 1
42on successful verification, 0 otherwise.
43
44The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
45
46=head1 BUGS
47
48Certain signatures with an improper algorithm identifier are accepted
49for compatibility with SSLeay 0.4.5 :-)
50
51=head1 CONFORMING TO
52
53SSL, PKCS #1 v2.0
54
55=head1 SEE ALSO
56
57L<ERR_get_error(3)|ERR_get_error(3)>, L<objects(3)|objects(3)>,
58L<rsa(3)|rsa(3)>, L<RSA_private_encrypt(3)|RSA_private_encrypt(3)>,
59L<RSA_public_decrypt(3)|RSA_public_decrypt(3)> 
60
61=head1 HISTORY
62
63RSA_sign() and RSA_verify() are available in all versions of SSLeay
64and OpenSSL.
65
66=cut
67