diff --git a/src/diagrams/git/gitGraphAst.js b/src/diagrams/git/gitGraphAst.js
index d1b86bfe4..81bcd60d0 100644
--- a/src/diagrams/git/gitGraphAst.js
+++ b/src/diagrams/git/gitGraphAst.js
@@ -9,7 +9,7 @@ let seq = 0;
 
 function makeid(length) {
   var result = '';
-  var characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+  var characters = '0123456789abcdef';
   var charactersLength = characters.length;
   for (var i = 0; i < length; i++) {
     result += characters.charAt(Math.floor(Math.random() * charactersLength));