diff --git a/system/crypt.php b/system/crypt.php index 46edb0f9..fc338de9 100644 --- a/system/crypt.php +++ b/system/crypt.php @@ -25,7 +25,8 @@ class Crypt { public static function encrypt($value) { // ----------------------------------------------------- - // Determine the input vector source. + // Determine the input vector source. Different servers + // and operating systems will have varying options. // ----------------------------------------------------- if (defined('MCRYPT_DEV_URANDOM')) { @@ -41,21 +42,19 @@ class Crypt { } // ----------------------------------------------------- - // The system random number generator must be seeded. + // The system random number generator must be seeded + // to produce adequately random results. // ----------------------------------------------------- if ($random === MCRYPT_RAND) { mt_srand(); } - // ----------------------------------------------------- - // Create the Mcrypt input vector and encrypt the value. - // ----------------------------------------------------- $iv = mcrypt_create_iv(static::iv_size(), $random); $value = mcrypt_encrypt(static::$cipher, static::key(), $value, static::$mode, $iv); // ----------------------------------------------------- - // Use base64 encoding to get a string value. + // We use base64 encoding to get a nice string value. // ----------------------------------------------------- return base64_encode($iv.$value); } @@ -68,6 +67,10 @@ class Crypt { */ public static function decrypt($value) { + // ----------------------------------------------------- + // Since all of our encrypted values are base64 encoded, + // we will decode the value here and verify it. + // ----------------------------------------------------- $value = base64_decode($value, true); if ( ! $value) @@ -81,7 +84,7 @@ class Crypt { $iv = substr($value, 0, static::iv_size()); // ----------------------------------------------------- - // Remove the input vector from the value. + // Remove the input vector from the encrypted value. // ----------------------------------------------------- $value = substr($value, static::iv_size()); @@ -106,6 +109,8 @@ class Crypt { /** * Get the input vector size for the cipher and mode. * + * Different ciphers and modes use varying lengths of input vectors. + * * @return int */ private static function iv_size()