diff --git a/src/script.js b/src/script.js
index 8264737..07f8551 100644
--- a/src/script.js
+++ b/src/script.js
@@ -210,14 +210,16 @@ function isWitnessPubKeyHashOutput (script) {
   var buffer = compile(script)
 
   return buffer.length === 22 &&
-    buffer[0] === OPS.OP_0
+    buffer[0] === OPS.OP_0 &&
+    buffer[1] === 0x14
 }
 
 function isWitnessScriptHashOutput (script) {
   var buffer = compile(script)
 
   return buffer.length === 34 &&
-    buffer[0] === OPS.OP_0
+    buffer[0] === OPS.OP_0 &&
+    buffer[1] === 0x20
 }
 
 // allowIncomplete is to account for combining signatures