X509_SIGN

Section: OpenSSL (3)
Updated: 2021-03-26
Page Index

NAME

X509_sign, X509_sign_ctx, X509_verify, X509_REQ_sign, X509_REQ_sign_ctx, X509_REQ_verify, X509_CRL_sign, X509_CRL_sign_ctx, X509_CRL_verify - sign or verify certificate, certificate request or CRL signature

SYNOPSIS

 #include <openssl/x509.h>

 int X509_sign(X509 *x, EVP_PKEY *pkey, const EVP_MD *md);
 int X509_sign_ctx(X509 *x, EVP_MD_CTX *ctx);
 int X509_verify(X509 *a, EVP_PKEY *r);

 int X509_REQ_sign(X509_REQ *x, EVP_PKEY *pkey, const EVP_MD *md);
 int X509_REQ_sign_ctx(X509_REQ *x, EVP_MD_CTX *ctx);
 int X509_REQ_verify(X509_REQ *a, EVP_PKEY *r);

 int X509_CRL_sign(X509_CRL *x, EVP_PKEY *pkey, const EVP_MD *md);
 int X509_CRL_sign_ctx(X509_CRL *x, EVP_MD_CTX *ctx);
 int X509_CRL_verify(X509_CRL *a, EVP_PKEY *r);

DESCRIPTION

X509_sign() signs certificate x using private key pkey and message digest md and sets the signature in x. X509_sign_ctx() also signs certificate x but uses the parameters contained in digest context ctx.

X509_verify() verifies the signature of certificate x using public key pkey. Only the signature is checked: no other checks (such as certificate chain validity) are performed.

X509_REQ_sign(), X509_REQ_sign_ctx(), X509_REQ_verify(), X509_CRL_sign(), X509_CRL_sign_ctx() and X509_CRL_verify() sign and verify certificate requests and CRLs respectively.

NOTES

X509_sign_ctx() is used where the default parameters for the corresponding public key and digest are not suitable. It can be used to sign keys using RSA-PSS for example.

For efficiency reasons and to work around ASN.1 encoding issues the encoding of the signed portion of a certificate, certificate request and CRL is cached internally. If the signed portion of the structure is modified the encoding is not always updated meaning a stale version is sometimes used. This is not normally a problem because modifying the signed portion will invalidate the signature and signing will always update the encoding.

RETURN VALUES

X509_sign(), X509_sign_ctx(), X509_REQ_sign(), X509_REQ_sign_ctx(), X509_CRL_sign() and X509_CRL_sign_ctx() return the size of the signature in bytes for success and zero for failure.

X509_verify(), X509_REQ_verify() and X509_CRL_verify() return 1 if the signature is valid and 0 if the signature check fails. If the signature could not be checked at all because it was invalid or some other error occurred then -1 is returned.

HISTORY

The X509_sign(), X509_REQ_sign() and X509_CRL_sign() functions are available in all versions of OpenSSL.

The X509_sign_ctx(), X509_REQ_sign_ctx() and X509_CRL_sign_ctx() functions were added OpenSSL 1.0.1.

COPYRIGHT

Licensed under the OpenSSL license (the ``License''). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.