diff --git a/src/type/keyid.js b/src/type/keyid.js
index fb5e06fc..08ef9e0f 100644
--- a/src/type/keyid.js
+++ b/src/type/keyid.js
@@ -28,9 +28,9 @@
 
 'use strict';
 
-module.exports = Keyid;
+import util from '../util.js';
 
-var util = require('../util.js');
+module.exports = Keyid;
 
 /**
  * @constructor
diff --git a/src/type/mpi.js b/src/type/mpi.js
index 0fc8bf5c..d60cbd19 100644
--- a/src/type/mpi.js
+++ b/src/type/mpi.js
@@ -36,10 +36,10 @@
 
 'use strict';
 
-module.exports = MPI;
+import BigInteger from '../crypto/public_key/jsbn.js';
+import util from '../util.js';
 
-var BigInteger = require('../crypto/public_key/jsbn.js'),
-  util = require('../util.js');
+module.exports = MPI;
 
 /**
  * @constructor
diff --git a/src/type/s2k.js b/src/type/s2k.js
index 82e73a1f..752306cd 100644
--- a/src/type/s2k.js
+++ b/src/type/s2k.js
@@ -31,11 +31,11 @@
 
 'use strict';
 
-module.exports = S2K;
+import enums from '../enums.js';
+import util from '../util.js';
+import crypto from '../crypto';
 
-var enums = require('../enums.js'),
-  util = require('../util.js'),
-  crypto = require('../crypto');
+module.exports = S2K;
 
 /**
  * @constructor