X509_check_ca.3ossl - Man Page

check if given certificate is CA certificate

Synopsis

 #include <openssl/x509v3.h>

 int X509_check_ca(X509 *cert);

Description

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4, if it is certificate with keyUsage extension with bit keyCertSign set, but without basicConstraints, and 5 if it has outdated Netscape Certificate Type extension telling that it is CA certificate.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.

See Also

X509_verify_cert(3), X509_check_issued(3), X509_check_purpose(3)

Referenced By

EVP_PKEY_ASN1_METHOD.3ossl(3), X509_check_issued.3ossl(3).

2021-09-09 3.0.0 OpenSSL