OCSP_REQUEST_ADD1_NONCE(3)                            Library Functions Manual

NAME
     OCSP_request_add1_nonce, OCSP_basic_add1_nonce, OCSP_check_nonce,
     OCSP_copy_nonce - OCSP nonce functions

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_check_nonce(OCSP_REQUEST *req, OCSP_BASICRESP *resp);

     int
     OCSP_copy_nonce(OCSP_BASICRESP *resp, OCSP_REQUEST *req);

DESCRIPTION
     An OCSP nonce is typically added to an OCSP request to thwart replay
     attacks by checking the same nonce value appears in the response.

     OCSP_request_add1_nonce() adds a nonce of value val and length len to
     OCSP request req.  If val is NULL, a random nonce is used.  If len is
     zero or negative, a default length will be used (currently 16 bytes).
     For most purposes the nonce value in a request is set to a random value
     so the val parameter in OCSP_request_add1_nonce() is usually NULL.

     OCSP_basic_add1_nonce() is identical to OCSP_request_add1_nonce() except
     it adds a nonce to OCSP basic response resp.

     OCSP_check_nonce() compares the nonce value in req and resp.

     OCSP_copy_nonce() copies any nonce value present in req to resp.

     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.

RETURN VALUES
     OCSP_request_add1_nonce() and OCSP_basic_add1_nonce() return 1 for
     success or 0 for failure.

     OCSP_copy_nonce() returns 1 if a nonce was successfully copied, 2 if no
     nonce was present in req, or 0 if an error occurred.

     OCSP_check_nonce() returns positive values for success: 1 if nonces are
     present and equal, 2 if both nonces are absent, or 3 if a nonce is
     present in the response only.  A zero return value indicates that both
     nonces are present but mismatch: this should be treated as an error
     condition.  A return value of -1 indicates that a nonce is present in the
     request only: this will happen if the responder doesn't support nonces.

SEE ALSO
     OCSP_cert_to_id(3), OCSP_REQUEST_new(3), OCSP_resp_find_status(3),
     OCSP_response_status(3), OCSP_sendreq_new(3)

HISTORY
     These functions first appeared in OpenSSL 0.9.7 and have been available
     since OpenBSD 3.2.

Linux 6.8.7-arch1-1             March 22, 2018             Linux 6.8.7-arch1-1