PHP: openssl_x509_checkpurpose function - Verifies if a certificate can be used for a particular purpose

Description

int openssl_x509_checkpurpose ( mixed $x509cert , int $purpose [, array $cainfo [, string $untrustedfile ]] )

openssl_x509_checkpurpose() examines a certificate to see if it can be used for the specified purpose .

Parameters

x509cert

The examined certificate.

purpose

**openssl_x509_checkpurpose()** purposes
Constant	Description
X509_PURPOSE_SSL_CLIENT	Can the certificate be used for the client side of an SSL connection?
X509_PURPOSE_SSL_SERVER	Can the certificate be used for the server side of an SSL connection?
X509_PURPOSE_NS_SSL_SERVER	Can the cert be used for Netscape SSL server?
X509_PURPOSE_SMIME_SIGN	Can the cert be used to sign S/MIME email?
X509_PURPOSE_SMIME_ENCRYPT	Can the cert be used to encrypt S/MIME email?
X509_PURPOSE_CRL_SIGN	Can the cert be used to sign a certificate revocation list (CRL)?
X509_PURPOSE_ANY	Can the cert be used for Any/All purposes?

These options are not bitfields - you may specify one only!

cainfo

cainfo should be an array of trusted CA files/dirs as described in Certificate Verification. It defaults to an empty array.

untrustedfile

If specified, this should be the name of a PEM encoded file holding certificates that can be used to help verify the certificate, although no trust in placed in the certificates that come from that file.

Return Values

Returns TRUE if the certificate can be used for the intended purpose, FALSE if it cannot, or -1 on error.