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.