(PHP 4 >= 4.0.6, PHP 5, PHP 7) Encrypts data with private key

(PHP 4 >= 4.0.4, PHP 5, PHP 7) Free key resource

(PHP 5 >= 5.6.0, PHP 7) Exports the challenge assoicated with a signed public key and challenge

(PHP 4 >= 4.0.4, PHP 5, PHP 7) Generate signature

(PHP 4 >= 4.0.4, PHP 5, PHP 7) Verify signature

(PHP 5 >= 5.6.0, PHP 7) Retrieve the available certificate locations

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Encrypt an S/MIME message

(PHP 5 >= 5.6.0, PHP 7) Exports a valid PEM formatted public key signed public key and challenge

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Checks if a private key corresponds to a certificate

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Return openSSL error message