diff --git a/lib/bcoin/bip151.js b/lib/bcoin/bip151.js
index e92390b5..662813dc 100644
--- a/lib/bcoin/bip151.js
+++ b/lib/bcoin/bip151.js
@@ -202,8 +202,7 @@ BIP151Stream.prototype.getPublicKey = function getPublicKey() {
 BIP151Stream.prototype.encryptSize = function encryptSize(size) {
   var data = new Buffer(4);
   data.writeUInt32LE(size, 0, true);
-  this.chacha.encrypt(data);
-  return data;
+  return this.chacha.encrypt(data);
 };
 
 /**