3 OCSP_request_add1_nonce, OCSP_basic_add1_nonce, OCSP_check_nonce, OCSP_copy_nonce - OCSP nonce functions.
7 #include <openssl/ocsp.h>
9 int OCSP_request_add1_nonce(OCSP_REQUEST *req, unsigned char *val, int len);
10 int OCSP_basic_add1_nonce(OCSP_BASICRESP *resp, unsigned char *val, int len);
11 int OCSP_copy_nonce(OCSP_BASICRESP *resp, OCSP_REQUEST *req);
12 int OCSP_check_nonce(OCSP_REQUEST *req, OCSP_BASICRESP *resp);
16 OCSP_request_add1_nonce() adds a nonce of value B<val> and length B<len> to
17 OCSP request B<req>. If B<val> is B<NULL> a random nonce is used. If B<len>
18 is zero or negative a default length will be used (currently 16 bytes).
20 OCSP_basic_add1_nonce() is identical to OCSP_request_add1_nonce() except
21 it adds a nonce to OCSP basic response B<resp>.
23 OCSP_check_nonce() compares the nonce value in B<req> and B<resp>.
25 OCSP_copy_nonce() copys any nonce value present in B<req> to B<resp>.
29 OCSP_request_add1_nonce() and OCSP_basic_add1_nonce() return 1 for success
32 OCSP_copy_nonce() returns 1 if a nonce was successfully copied, 2 if no nonce
33 was present in B<req> and 0 if an error occurred.
35 OCSP_check_nonce() returns the result of the nonce comparison between B<req>
36 and B<resp>. The return value indicates the result of the comparison. If
37 nonces are present and equal 1 is returned. If the nonces are absent 2 is
38 returned. If a nonce is present in the response only 3 is returned. If nonces
39 are present and unequal 0 is returned. If the nonce is present in the request
40 only then -1 is returned.
44 For most purposes the nonce value in a request is set to a random value so
45 the B<val> parameter in OCSP_request_add1_nonce() is usually NULL.
47 An OCSP nonce is typically added to an OCSP request to thwart replay attacks
48 by checking the same nonce value appears in the response.
50 Some responders may include a nonce in all responses even if one is not
53 Some responders cache OCSP responses and do not sign each response for
54 performance reasons. As a result they do not support nonces.
56 The return values of OCSP_check_nonce() can be checked to cover each case. A
57 positive return value effectively indicates success: nonces are both present
58 and match, both absent or present in the response only. A non-zero return
59 additionally covers the case where the nonce is present in the request only:
60 this will happen if the responder doesn't support nonces. A zero return value
61 indicates present and mismatched nonces: this should be treated as an error
67 L<OCSP_cert_to_id(3)>,
68 L<OCSP_REQUEST_new(3)>,
69 L<OCSP_response_find_status(3)>,
70 L<OCSP_response_status(3)>,
71 L<OCSP_sendreq_new(3)>