diff --git a/lib/pool.js b/lib/pool.js
index f2084b9..2114211 100644
--- a/lib/pool.js
+++ b/lib/pool.js
@@ -22,7 +22,7 @@ let httpResponse = ' 200 OK\nContent-Type: text/plain\nContent-Length: 18\n\nMin
 let threadName;
 let minerCount = [];
 let BlockTemplate = global.coinFuncs.BlockTemplate;
-let hexMatch = new RegExp("^[0-9a-f]$");
+let hexMatch = new RegExp("^[0-9a-f]+$");
 
 Buffer.prototype.toByteArray = function () {
     return Array.prototype.slice.call(this, 0);