Use OpenSSL for CAST5

Mcrypt is deprecated, so use OpenSSL when we can, mcrypt when we can't.

lib/openpgp_openssl_wrapper.php

@@ -0,0 +1,33 @@
+<?php
+
+if(function_exists('openssl_encrypt')) {
+  class OpenSSLWrapper {
+    public $cipher, $key, $iv, $key_size, $block_size;
+
+
+    function __construct($cipher) {
+      if($cipher != "CAST5-CFB") throw Exception("OpenSSLWrapper is only used for CAST5 right now");
+
+      $this->cipher = $cipher;
+      $this->key_size = 16;
+      $this->block_size = 8;
+      $this->iv = str_repeat("\0", 8);
+    }
+
+    function setKey($key) {
+      $this->key = $key;
+    }
+
+    function setIV($iv) {
+      $this->iv = $iv;
+    }
+
+    function encrypt($data) {
+      return openssl_encrypt($data, $this->cipher, $this->key, OPENSSL_RAW_DATA|OPENSSL_ZERO_PADDING, $this->iv);
+    }
+
+    function decrypt($data) {
+      return openssl_decrypt($data, $this->cipher, $this->key, OPENSSL_RAW_DATA|OPENSSL_ZERO_PADDING, $this->iv);
+    }
+  }
+}