1=pod 2 3=head1 NAME 4 5X509_verify, X509_self_signed, 6X509_REQ_verify_ex, X509_REQ_verify, 7X509_CRL_verify - 8verify certificate, certificate request, or CRL signature 9 10=head1 SYNOPSIS 11 12 #include <openssl/x509.h> 13 14 int X509_verify(X509 *x, EVP_PKEY *pkey); 15 int X509_self_signed(X509 *cert, int verify_signature); 16 17 int X509_REQ_verify_ex(X509_REQ *a, EVP_PKEY *pkey, OSSL_LIB_CTX *libctx, 18 const char *propq); 19 int X509_REQ_verify(X509_REQ *a, EVP_PKEY *r); 20 int X509_CRL_verify(X509_CRL *a, EVP_PKEY *r); 21 22=head1 DESCRIPTION 23 24X509_verify() verifies the signature of certificate I<x> using public key 25I<pkey>. Only the signature is checked: no other checks (such as certificate 26chain validity) are performed. 27 28X509_self_signed() checks whether certificate I<cert> is self-signed. 29For success the issuer and subject names must match, the components of the 30authority key identifier (if present) must match the subject key identifier etc. 31The signature itself is actually verified only if B<verify_signature> is 1, as 32for explicitly trusted certificates this verification is not worth the effort. 33 34X509_REQ_verify_ex(), X509_REQ_verify() and X509_CRL_verify() 35verify the signatures of certificate requests and CRLs, respectively. 36 37=head1 RETURN VALUES 38 39X509_verify(), 40X509_REQ_verify_ex(), X509_REQ_verify() and X509_CRL_verify() 41return 1 if the signature is valid and 0 if the signature check fails. 42If the signature could not be checked at all because it was ill-formed, 43the certificate or the request was not complete or some other error occurred 44then -1 is returned. 45 46X509_self_signed() returns the same values but also returns 1 47if all respective fields match and B<verify_signature> is 0. 48 49=head1 SEE ALSO 50 51L<d2i_X509(3)>, 52L<ERR_get_error(3)>, 53L<X509_CRL_get0_by_serial(3)>, 54L<X509_get0_signature(3)>, 55L<X509_get_ext_d2i(3)>, 56L<X509_get_extension_flags(3)>, 57L<X509_get_pubkey(3)>, 58L<X509_get_subject_name(3)>, 59L<X509_get_version(3)>, 60L<X509_NAME_ENTRY_get_object(3)>, 61L<X509_NAME_get_index_by_NID(3)>, 62L<X509_NAME_print_ex(3)>, 63L<X509V3_get_d2i(3)>, 64L<X509_verify_cert(3)>, 65L<OSSL_LIB_CTX(3)> 66 67=head1 HISTORY 68 69The X509_verify(), X509_REQ_verify(), and X509_CRL_verify() 70functions are available in all versions of OpenSSL. 71 72X509_REQ_verify_ex(), and X509_self_signed() were added in OpenSSL 3.0. 73 74=head1 COPYRIGHT 75 76Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved. 77 78Licensed under the Apache License 2.0 (the "License"). You may not use 79this file except in compliance with the License. You can obtain a copy 80in the file LICENSE in the source distribution or at 81L<https://www.openssl.org/source/license.html>. 82 83=cut 84