diff --git a/src/templates/pubkey/input.js b/src/templates/pubkey/input.js
index 0e8ed8d..1d34cb4 100644
--- a/src/templates/pubkey/input.js
+++ b/src/templates/pubkey/input.js
@@ -1,7 +1,6 @@
 // {signature}
 
 var bscript = require('../../script')
-var types = require('../../types')
 var typeforce = require('typeforce')
 
 function check (script) {
@@ -13,7 +12,7 @@ function check (script) {
 check.toJSON = function () { return 'pubKey input' }
 
 function encodeStack (signature) {
-  typeforce(types.Buffer, signature)
+  typeforce(bscript.isCanonicalSignature, signature)
   return [signature]
 }