| =pod |
| |
| =head1 NAME |
| |
| OCSP_request_add1_nonce, OCSP_basic_add1_nonce, OCSP_check_nonce, OCSP_copy_nonce - OCSP nonce functions |
| |
| =head1 SYNOPSIS |
| |
| #include <openssl/ocsp.h> |
| |
| int OCSP_request_add1_nonce(OCSP_REQUEST *req, unsigned char *val, int len); |
| int OCSP_basic_add1_nonce(OCSP_BASICRESP *resp, unsigned char *val, int len); |
| int OCSP_copy_nonce(OCSP_BASICRESP *resp, OCSP_REQUEST *req); |
| int OCSP_check_nonce(OCSP_REQUEST *req, OCSP_BASICRESP *resp); |
| |
| =head1 DESCRIPTION |
| |
| OCSP_request_add1_nonce() adds a nonce of value B<val> and length B<len> to |
| OCSP request B<req>. If B<val> is B<NULL> a random nonce is used. If B<len> |
| is zero or negative a default length will be used (currently 16 bytes). |
| |
| OCSP_basic_add1_nonce() is identical to OCSP_request_add1_nonce() except |
| it adds a nonce to OCSP basic response B<resp>. |
| |
| OCSP_check_nonce() compares the nonce value in B<req> and B<resp>. |
| |
| OCSP_copy_nonce() copies any nonce value present in B<req> to B<resp>. |
| |
| =head1 RETURN VALUES |
| |
| OCSP_request_add1_nonce() and OCSP_basic_add1_nonce() return 1 for success |
| and 0 for failure. |
| |
| OCSP_copy_nonce() returns 1 if a nonce was successfully copied, 2 if no nonce |
| was present in B<req> and 0 if an error occurred. |
| |
| OCSP_check_nonce() returns the result of the nonce comparison between B<req> |
| and B<resp>. The return value indicates the result of the comparison. If |
| nonces are present and equal 1 is returned. If the nonces are absent 2 is |
| returned. If a nonce is present in the response only 3 is returned. If nonces |
| are present and unequal 0 is returned. If the nonce is present in the request |
| only then -1 is returned. |
| |
| =head1 NOTES |
| |
| For most purposes the nonce value in a request is set to a random value so |
| the B<val> parameter in OCSP_request_add1_nonce() is usually NULL. |
| |
| An OCSP nonce is typically added to an OCSP request to thwart replay attacks |
| by checking the same nonce value appears in the response. |
| |
| Some responders may include a nonce in all responses even if one is not |
| supplied. |
| |
| Some responders cache OCSP responses and do not sign each response for |
| performance reasons. As a result they do not support nonces. |
| |
| The return values of OCSP_check_nonce() can be checked to cover each case. A |
| positive return value effectively indicates success: nonces are both present |
| and match, both absent or present in the response only. A nonzero return |
| additionally covers the case where the nonce is present in the request only: |
| this will happen if the responder doesn't support nonces. A zero return value |
| indicates present and mismatched nonces: this should be treated as an error |
| condition. |
| |
| =head1 SEE ALSO |
| |
| L<crypto(7)>, |
| L<OCSP_cert_to_id(3)>, |
| L<OCSP_REQUEST_new(3)>, |
| L<OCSP_resp_find_status(3)>, |
| L<OCSP_response_status(3)>, |
| L<OCSP_sendreq_new(3)> |
| |
| =head1 COPYRIGHT |
| |
| Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved. |
| |
| Licensed under the Apache License 2.0 (the "License"). You may not use |
| this file except in compliance with the License. You can obtain a copy |
| in the file LICENSE in the source distribution or at |
| L<https://www.openssl.org/source/license.html>. |
| |
| =cut |
