diff --git a/lib/acme-client.js b/lib/acme-client.js
index b5755d5..cb9a320 100644
--- a/lib/acme-client.js
+++ b/lib/acme-client.js
@@ -13,8 +13,8 @@ module.exports.create = function (deps) {
   var request=require('request');
   var generateSignature=deps.RSA.signJws;
 
-  function Acme(privateKey) {
-    this.privateKey=privateKey;
+  function Acme(keypair) {
+    this.keypair;
     this.nonces=[];
   }
 
@@ -54,7 +54,7 @@ module.exports.create = function (deps) {
     log('Using nonce: '+this.nonces[0]);
     payload=JSON.stringify(body, null, 2);
     jws=generateSignature(
-        this.privateKey, new Buffer(payload), this.nonces.shift()
+        this.keypair, new Buffer(payload), this.nonces.shift()
     );
     signed=JSON.stringify(jws, null, 2);