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X509_verify(3)                      OpenSSL                     X509_verify(3)



NAME
       X509_verify, X509_self_signed, X509_REQ_verify_ex, X509_REQ_verify,
       X509_CRL_verify - verify certificate, certificate request, or CRL
       signature

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/x509.h>

        int X509_verify(X509 *x, EVP_PKEY *pkey);
        int X509_self_signed(X509 *cert, int verify_signature);

        int X509_REQ_verify_ex(X509_REQ *a, EVP_PKEY *pkey, OSSL_LIB_CTX *libctx,
                               const char *propq);
        int X509_REQ_verify(X509_REQ *a, EVP_PKEY *r);
        int X509_CRL_verify(X509_CRL *a, EVP_PKEY *r);

DESCRIPTION
       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_self_signed() checks whether certificate cert is self-signed.  For
       success the issuer and subject names must match, the components of the
       authority key identifier (if present) must match the subject key
       identifier etc.  The signature itself is actually verified only if
       verify_signature is 1, as for explicitly trusted certificates this
       verification is not worth the effort.

       X509_REQ_verify_ex(), X509_REQ_verify() and X509_CRL_verify() verify
       the signatures of certificate requests and CRLs, respectively.

RETURN VALUES
       X509_verify(), X509_REQ_verify_ex(), 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 ill-formed, the certificate or the request was not
       complete or some other error occurred then -1 is returned.

       X509_self_signed() returns the same values but also returns 1 if all
       respective fields match and verify_signature is 0.

SEE ALSO
       d2i_X509(3), ERR_get_error(3), X509_CRL_get0_by_serial(3),
       X509_get0_signature(3), X509_get_ext_d2i(3),
       X509_get_extension_flags(3), X509_get_pubkey(3),
       X509_get_subject_name(3), X509_get_version(3),
       X509_NAME_ENTRY_get_object(3), X509_NAME_get_index_by_NID(3),
       X509_NAME_print_ex(3), X509V3_get_d2i(3), X509_verify_cert(3),
       OSSL_LIB_CTX(3)

HISTORY
       The X509_verify(), X509_REQ_verify(), and X509_CRL_verify() functions
       are available in all versions of OpenSSL.

       X509_REQ_verify_ex(), and X509_self_signed() were added in OpenSSL 3.0.

COPYRIGHT
       Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (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>.



3.0.12                            2023-05-07                    X509_verify(3)