1OCSP_REQUEST_ADD1_NONCE(3)          OpenSSL         OCSP_REQUEST_ADD1_NONCE(3)
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NAME

6       OCSP_request_add1_nonce, OCSP_basic_add1_nonce, OCSP_check_nonce,
7       OCSP_copy_nonce - OCSP nonce functions
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SYNOPSIS

10        #include <openssl/ocsp.h>
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12        int OCSP_request_add1_nonce(OCSP_REQUEST *req, unsigned char *val, int len);
13        int OCSP_basic_add1_nonce(OCSP_BASICRESP *resp, unsigned char *val, int len);
14        int OCSP_copy_nonce(OCSP_BASICRESP *resp, OCSP_REQUEST *req);
15        int OCSP_check_nonce(OCSP_REQUEST *req, OCSP_BASICRESP *resp);
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DESCRIPTION

18       OCSP_request_add1_nonce() adds a nonce of value val and length len to
19       OCSP request req. If val is NULL a random nonce is used. If len is zero
20       or negative a default length will be used (currently 16 bytes).
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22       OCSP_basic_add1_nonce() is identical to OCSP_request_add1_nonce()
23       except it adds a nonce to OCSP basic response resp.
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25       OCSP_check_nonce() compares the nonce value in req and resp.
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27       OCSP_copy_nonce() copies any nonce value present in req to resp.
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RETURN VALUES

30       OCSP_request_add1_nonce() and OCSP_basic_add1_nonce() return 1 for
31       success and 0 for failure.
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33       OCSP_copy_nonce() returns 1 if a nonce was successfully copied, 2 if no
34       nonce was present in req and 0 if an error occurred.
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36       OCSP_check_nonce() returns the result of the nonce comparison between
37       req and resp. The return value indicates the result of the comparison.
38       If nonces are present and equal 1 is returned. If the nonces are absent
39       2 is returned. If a nonce is present in the response only 3 is
40       returned. If nonces are present and unequal 0 is returned. If the nonce
41       is present in the request only then -1 is returned.
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NOTES

44       For most purposes the nonce value in a request is set to a random value
45       so the val parameter in OCSP_request_add1_nonce() is usually NULL.
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47       An OCSP nonce is typically added to an OCSP request to thwart replay
48       attacks by checking the same nonce value appears in the response.
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50       Some responders may include a nonce in all responses even if one is not
51       supplied.
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53       Some responders cache OCSP responses and do not sign each response for
54       performance reasons. As a result they do not support nonces.
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56       The return values of OCSP_check_nonce() can be checked to cover each
57       case.  A positive return value effectively indicates success: nonces
58       are both present and match, both absent or present in the response
59       only. A nonzero return additionally covers the case where the nonce is
60       present in the request only: this will happen if the responder doesn't
61       support nonces. A zero return value indicates present and mismatched
62       nonces: this should be treated as an error condition.
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SEE ALSO

65       crypto(7), OCSP_cert_to_id(3), OCSP_REQUEST_new(3),
66       OCSP_resp_find_status(3), OCSP_response_status(3), OCSP_sendreq_new(3)
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69       Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
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71       Licensed under the OpenSSL license (the "License").  You may not use
72       this file except in compliance with the License.  You can obtain a copy
73       in the file LICENSE in the source distribution or at
74       <https://www.openssl.org/source/license.html>.
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781.1.1q                            2023-02-06        OCSP_REQUEST_ADD1_NONCE(3)
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