.\" $OpenBSD: OCSP_request_add1_nonce.3,v 1.4 2018/03/22 21:08:22 schwarze Exp $ .\" OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100 .\" .\" This file was written by Dr. Stephen Henson <steve@openssl.org>. .\" Copyright (c) 2014, 2016 The OpenSSL Project. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in .\" the documentation and/or other materials provided with the .\" distribution. .\" .\" 3. 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IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: March 22 2018 $ .Dt OCSP_REQUEST_ADD1_NONCE 3 .Os .Sh NAME .Nm OCSP_request_add1_nonce , .Nm OCSP_basic_add1_nonce , .Nm OCSP_check_nonce , .Nm OCSP_copy_nonce .Nd OCSP nonce functions .Sh SYNOPSIS .In openssl/ocsp.h .Ft int .Fo OCSP_request_add1_nonce .Fa "OCSP_REQUEST *req" .Fa "unsigned char *val" .Fa "int len" .Fc .Ft int .Fo OCSP_basic_add1_nonce .Fa "OCSP_BASICRESP *resp" .Fa "unsigned char *val" .Fa "int len" .Fc .Ft int .Fo OCSP_check_nonce .Fa "OCSP_REQUEST *req" .Fa "OCSP_BASICRESP *resp" .Fc .Ft int .Fo OCSP_copy_nonce .Fa "OCSP_BASICRESP *resp" .Fa "OCSP_REQUEST *req" .Fc .Sh 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. .Pp .Fn OCSP_request_add1_nonce adds a nonce of value .Fa val and length .Fa len to OCSP request .Fa req . If .Fa val is .Dv NULL , a random nonce is used. If .Fa 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 .Fa val parameter in .Fn OCSP_request_add1_nonce is usually NULL. .Pp .Fn OCSP_basic_add1_nonce is identical to .Fn OCSP_request_add1_nonce except it adds a nonce to OCSP basic response .Fa resp . .Pp .Fn OCSP_check_nonce compares the nonce value in .Fa req and .Fa resp . .Pp .Fn OCSP_copy_nonce copies any nonce value present in .Fa req to .Fa resp . .Pp Some responders may include a nonce in all responses even if one is not supplied. .Pp Some responders cache OCSP responses and do not sign each response for performance reasons. As a result they do not support nonces. .Sh RETURN VALUES .Fn OCSP_request_add1_nonce and .Fn OCSP_basic_add1_nonce return 1 for success or 0 for failure. .Pp .Fn OCSP_copy_nonce returns 1 if a nonce was successfully copied, 2 if no nonce was present in .Fa req , or 0 if an error occurred. .Pp .Fn 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. .Sh SEE ALSO .Xr OCSP_cert_to_id 3 , .Xr OCSP_REQUEST_new 3 , .Xr OCSP_resp_find_status 3 , .Xr OCSP_response_status 3 , .Xr OCSP_sendreq_new 3 .Sh HISTORY These functions first appeared in OpenSSL 0.9.7 and have been available since .Ox 3.2 .