diff --git a/lib/resource/lock/Lock.js b/lib/resource/lock/Lock.js
index fe811512..c54c6374 100644
--- a/lib/resource/lock/Lock.js
+++ b/lib/resource/lock/Lock.js
@@ -12,6 +12,8 @@ var Lock = (function () {
         var rnd1 = Math.ceil(Math.random() * 0x3FFF) + 0x8000;
         var rnd2 = Math.ceil(Math.random() * 0xFFFFFFFF);
         function pad(value, nb) {
+            if (value < 0)
+                value *= -1;
             var str = Math.ceil(value).toString(16);
             while (str.length < nb)
                 str = '0' + str;
diff --git a/src/resource/lock/Lock.ts b/src/resource/lock/Lock.ts
index df3512e1..21aa1879 100644
--- a/src/resource/lock/Lock.ts
+++ b/src/resource/lock/Lock.ts
@@ -13,6 +13,9 @@ export class Lock
 
         function pad(value : number, nb : number)
         {
+            if(value < 0)
+                value *= -1;
+            
             let str = Math.ceil(value).toString(16);
             while(str.length < nb)
                 str = '0' + str;