Crypt/GPG.php
public function encryptFile(
        $filename,
        $encryptedFile = null,
        $armor = self::ARMOR_ASCII
    ) {
        return $this->_encrypt($filename, true, $encryptedFile, $armor);
    }
public function encryptFile(
        $filename,
        $encryptedFile = null,
        $armor = self::ARMOR_ASCII
    ) {
        return $this->_encrypt($filename, true, $encryptedFile, $armor);
    }
Encrypts a file

Encrypted data is ASCII armored by default but may optionally be saved
as binary.

@param string  $filename      the filename of the file to encrypt.
@param string  $encryptedFile optional. The filename of the file in
which to store the encrypted data. If null
or unspecified, the encrypted data is
returned as a string.
@param boolean $armor         optional. If true, ASCII armored data is
returned; otherwise, binary data is
returned. Defaults to true.

@return void|string if the <kbd>$encryptedFile</kbd> parameter is null,
a string containing the encrypted data is returned.

@throws Crypt_GPG_KeyNotFoundException if no encryption key is specified.
See {@link Crypt_GPG::addEncryptKey()}.

@throws Crypt_GPG_FileException if the output file is not writeable or
if the input file is not readable.

@throws Crypt_GPG_Exception if an unknown or unexpected error occurs.
Use the <kbd>debug</kbd> option and file a bug report if these
exceptions occur.