Significant changes to the Encryption library
- Removed double-encoding with XOR scheme when Mcrypt is available. Additional obfuscation was not significantly aiding security, and came at a very high performance cost.
- Changed the default encryption mode from ECB to CBC for much improved security
- Added an encode_from_legacy() method to allow re-encoding of permanent data that was originally encoded with the older methods.
diff --git a/system/libraries/Encrypt.php b/system/libraries/Encrypt.php
index 44fdce0..8beff75 100644
--- a/system/libraries/Encrypt.php
+++ b/system/libraries/Encrypt.php
@@ -116,12 +116,16 @@
function encode($string, $key = '')
{
$key = $this->get_key($key);
- $enc = $this->_xor_encode($string, $key);
-
+
if ($this->_mcrypt_exists === TRUE)
{
- $enc = $this->mcrypt_encode($enc, $key);
+ $enc = $this->mcrypt_encode($string, $key);
}
+ else
+ {
+ $enc = $this->_xor_encode($string, $key);
+ }
+
return base64_encode($enc);
}
@@ -155,12 +159,71 @@
return FALSE;
}
}
-
- return $this->_xor_decode($dec, $key);
+ else
+ {
+ $dec = $this->_xor_decode($dec, $key);
+ }
+
+ return $dec;
}
// --------------------------------------------------------------------
+
+ /**
+ * Encode from Legacy
+ *
+ * Takes an encoded string from the original Encryption class algorithms and
+ * returns a newly encoded string using the improved method added in 2.0.0
+ * This allows for backwards compatibility and a method to transition to the
+ * new encryption algorithms.
+ *
+ * For more details, see http://codeigniter.com/user_guide/installation/upgrade_200.html#encryption
+ *
+ * @access public
+ * @param string
+ * @param int (mcrypt mode constant)
+ * @param string
+ * @return string
+ */
+ function encode_from_legacy($string, $legacy_mode = MCRYPT_MODE_ECB, $key = '')
+ {
+ if ($this->_mcrypt_exists === FALSE)
+ {
+ log_message('error', 'Encoding from legacy is available only when Mcrypt is in use.');
+ return FALSE;
+ }
+
+ // decode it first
+ // set mode temporarily to what it was when string was encoded with the legacy
+ // algorithm - typically MCRYPT_MODE_ECB
+ $current_mode = $this->_get_mode();
+ $this->set_mode($legacy_mode);
+
+ $key = $this->get_key($key);
+
+ if (preg_match('/[^a-zA-Z0-9\/\+=]/', $string))
+ {
+ return FALSE;
+ }
+ $dec = base64_decode($string);
+
+ if (($dec = $this->mcrypt_decode($dec, $key)) === FALSE)
+ {
+ return FALSE;
+ }
+
+ $dec = $this->_xor_decode($dec, $key);
+
+ // set the mcrypt mode back to what it should be, typically MCRYPT_MODE_CBC
+ $this->set_mode(MCRYPT_MODE_CBC);
+
+ // and re-encode
+ return base64_encode($this->mcrypt_encode($dec, $key));
+ }
+
+ // --------------------------------------------------------------------
+
/**
* XOR Encode
*
@@ -412,7 +475,7 @@
{
if ($this->_mcrypt_mode == '')
{
- $this->_mcrypt_mode = MCRYPT_MODE_ECB;
+ $this->_mcrypt_mode = MCRYPT_MODE_CBC;
}
return $this->_mcrypt_mode;