diff --git a/cake/libs/string.php b/cake/libs/string.php
index bda87238d..a85db0065 100644
--- a/cake/libs/string.php
+++ b/cake/libs/string.php
@@ -85,26 +85,49 @@ class String extends Object {
  */
 	function uuid() {
 		$node = env('SERVER_ADDR');
+		$pid = null;
 
-		if(empty($node)) {
+		if (strpos($node, ':') !== false) {
+			if (substr_count($node, '::')) {
+				$node = str_replace('::', str_repeat(':0000', 8 - substr_count($node, ':')) . ':', $node);
+			}
+			$node = explode(':', $node) ;
+			$ipv6 = '' ;
+
+			foreach ($node as $id) {
+				$ipv6 .= str_pad(base_convert($id, 16, 2), 16, 0, STR_PAD_LEFT);
+			}
+			$node =  base_convert($ipv6, 2, 10);
+
+			if (strlen($node) < 38) {
+				$node = null;
+			} else {
+				$node = crc32($node);
+			}
+		} elseif (empty($node)) {
 			$host = env('HOSTNAME');
 
 			if (empty($host)) {
 				$host = env('HOST');
 			}
 
-			if (empty($host)) {
-				$node = ip2long('127.0.0.1');
-			} else {
+			if (!empty($host)) {
 				$ip = gethostbyname($host);
+
 				if ($ip === $host) {
 					$node = crc32($host);
 				} else {
 					$node = ip2long($ip);
 				}
 			}
-		} else {
+		} elseif ($node !== '127.0.0.1') {
 			$node = ip2long($node);
+		} else {
+			$node = null;
+		}
+
+		if (empty($node)) {
+			$node = crc32(Configure::read('Security.salt'));
 		}
 
 		if (function_exists('zend_thread_id')) {
@@ -113,9 +136,14 @@ class String extends Object {
 			$pid = getmypid();
 		}
 
+		if (!$pid) {
+			$pid = mt_rand(0, 0xfff) | 0x4000;
+		}
+
 		list($timeMid, $timeLow) = explode(' ', microtime());
 		$uuid = sprintf("%08x-%04x-%04x-%02x%02x-%04x%08x", (int)$timeLow, (int)substr($timeMid, 2) & 0xffff,
-					mt_rand(0, 0xfff) | 0x4000, mt_rand(0, 0x3f) | 0x80, mt_rand(0, 0xff), $pid, $node);
+					mt_rand(0, 0xfff) | 0x4000, mt_rand(0, 0x3f) | 0x80, mt_rand(0, 0xff), substr($pid, 0, 5), $node);
+
 		return $uuid;
 	}
 /**