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797a89a1 DSH |
1 | =pod |
2 | ||
aec3ecd0 RL |
3 | =head1 NAME |
4 | ||
bb9ad09e | 5 | OCSP_request_add1_nonce, OCSP_basic_add1_nonce, OCSP_check_nonce, OCSP_copy_nonce - OCSP nonce functions |
797a89a1 DSH |
6 | |
7 | =head1 SYNOPSIS | |
8 | ||
9 | #include <openssl/ocsp.h> | |
10 | ||
11 | int OCSP_request_add1_nonce(OCSP_REQUEST *req, unsigned char *val, int len); | |
12 | int OCSP_basic_add1_nonce(OCSP_BASICRESP *resp, unsigned char *val, int len); | |
13 | int OCSP_copy_nonce(OCSP_BASICRESP *resp, OCSP_REQUEST *req); | |
14 | int OCSP_check_nonce(OCSP_REQUEST *req, OCSP_BASICRESP *resp); | |
15 | ||
16 | =head1 DESCRIPTION | |
17 | ||
18 | OCSP_request_add1_nonce() adds a nonce of value B<val> and length B<len> to | |
19 | OCSP request B<req>. If B<val> is B<NULL> a random nonce is used. If B<len> | |
20 | is zero or negative a default length will be used (currently 16 bytes). | |
21 | ||
22 | OCSP_basic_add1_nonce() is identical to OCSP_request_add1_nonce() except | |
23 | it adds a nonce to OCSP basic response B<resp>. | |
24 | ||
25 | OCSP_check_nonce() compares the nonce value in B<req> and B<resp>. | |
26 | ||
27 | OCSP_copy_nonce() copys any nonce value present in B<req> to B<resp>. | |
28 | ||
29 | =head1 RETURN VALUES | |
30 | ||
31 | OCSP_request_add1_nonce() and OCSP_basic_add1_nonce() return 1 for success | |
32 | and 0 for failure. | |
33 | ||
34 | OCSP_copy_nonce() returns 1 if a nonce was successfully copied, 2 if no nonce | |
35 | was present in B<req> and 0 if an error occurred. | |
36 | ||
37 | OCSP_check_nonce() returns the result of the nonce comparison between B<req> | |
38 | and B<resp>. The return value indicates the result of the comparison. If | |
39 | nonces are present and equal 1 is returned. If the nonces are absent 2 is | |
40 | returned. If a nonce is present in the response only 3 is returned. If nonces | |
41 | are present and unequal 0 is returned. If the nonce is present in the request | |
42 | only then -1 is returned. | |
43 | ||
44 | =head1 NOTES | |
45 | ||
46 | For most purposes the nonce value in a request is set to a random value so | |
47 | the B<val> parameter in OCSP_request_add1_nonce() is usually NULL. | |
48 | ||
49 | An OCSP nonce is typically added to an OCSP request to thwart replay attacks | |
50 | by checking the same nonce value appears in the response. | |
51 | ||
52 | Some responders may include a nonce in all responses even if one is not | |
53 | supplied. | |
54 | ||
55 | Some responders cache OCSP responses and do not sign each response for | |
56 | performance reasons. As a result they do not support nonces. | |
57 | ||
58 | The return values of OCSP_check_nonce() can be checked to cover each case. A | |
59 | positive return value effectively indicates success: nonces are both present | |
60 | and match, both absent or present in the response only. A non-zero return | |
61 | additionally covers the case where the nonce is present in the request only: | |
62 | this will happen if the responder doesn't support nonces. A zero return value | |
63 | indicates present and mismatched nonces: this should be treated as an error | |
64 | condition. | |
65 | ||
66 | =head1 SEE ALSO | |
67 | ||
b97fdb57 | 68 | L<crypto(7)>, |
9b86974e RS |
69 | L<OCSP_cert_to_id(3)>, |
70 | L<OCSP_REQUEST_new(3)>, | |
b97fdb57 | 71 | L<OCSP_resp_find_status(3)>, |
9b86974e RS |
72 | L<OCSP_response_status(3)>, |
73 | L<OCSP_sendreq_new(3)> | |
797a89a1 | 74 | |
e2f92610 RS |
75 | =head1 COPYRIGHT |
76 | ||
77 | Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved. | |
78 | ||
4746f25a | 79 | Licensed under the Apache License 2.0 (the "License"). You may not use |
e2f92610 RS |
80 | this file except in compliance with the License. You can obtain a copy |
81 | in the file LICENSE in the source distribution or at | |
82 | L<https://www.openssl.org/source/license.html>. | |
83 | ||
84 | =cut |