X509_check_ca3ssl

Usage

 #include <openssl/x509v3.h>
 int X509_check_ca(X509 *cert);

Overview

This function checks if given certificate is CA certificate (can be used to sign other certificates). The certificate must be a complete certificate otherwise an error is returned.

Return values

Function return 0, if it is not CA certificate, 1 if it is proper X509v3 CA certificate with basicConstraints extension CA:TRUE, 3, if it is self-signed X509 v1 certificate, 4, if it is certificate with keyUsage extension with bit keyCertSign set, but without basicConstraints, and 5 if it has outdated Netscape Certificate Type extension telling that it is CA certificate.

This function will also return 0 on error.

Actually, any nonzero value means that this certificate could have been used to sign other certificates.