diff --git a/lib/key-encoder.js b/lib/key-encoder.js
index 286e522..4e82651 100644
--- a/lib/key-encoder.js
+++ b/lib/key-encoder.js
@@ -4,6 +4,9 @@ var asn1 = require('asn1.js'),
     BN = require('bn.js'),
     EC = require('elliptic').ec
 
+// compatibility with asn1
+const Buffer = require('buffer').Buffer;
+
 var ECPrivateKeyASN = asn1.define('ECPrivateKey', function() {
     this.seq().obj(
         this.key('version').int(),
@@ -160,4 +163,4 @@ KeyEncoder.prototype.encodePublic = function(publicKey, originalFormat, destinat
     }
 }
 
-module.exports = KeyEncoder
\ No newline at end of file
+module.exports = KeyEncoder