simplify ECIES interface

the toKeypair doesn't really need to be a keypair. upon encrypting, it merely
needs to be a pubkey. and upon decrypting, it needs to be a privkey.

lib/expmt/ecies.js

@@ -3,6 +3,7 @@ var Keypair = require('../keypair');
 var Point = require('../point');
 var Hash = require('../hash');
 var Pubkey = require('../pubkey');
+var Privkey = require('../privkey');
 
 // http://en.wikipedia.org/wiki/Integrated_Encryption_Scheme
 var ECIES = function ECIES() {
@@ -10,14 +11,14 @@ var ECIES = function ECIES() {
     return new ECIES();
 };
 
-ECIES.encrypt = function(messagebuf, tokeypair, fromkeypair, ivbuf) {
+ECIES.encrypt = function(messagebuf, topubkey, fromkeypair, ivbuf) {
   if (!fromkeypair)
     fromkeypair = Keypair().fromRandom();
   var r = fromkeypair.privkey.bn;
   var R = fromkeypair.pubkey.point;
   var Rpubkey = fromkeypair.pubkey;
   var Rbuf = Rpubkey.toDER(true);
-  var KB = tokeypair.pubkey.point;
+  var KB = topubkey.point;
   var P = KB.mul(r);
   var S = P.getX();
   var Sbuf = S.toBuffer({size: 32});
@@ -30,8 +31,8 @@ ECIES.encrypt = function(messagebuf, tokeypair, fromkeypair, ivbuf) {
   return encbuf;
 };
 
-ECIES.decrypt = function(encbuf, tokeypair) {
-  var kB = tokeypair.privkey.bn;
+ECIES.decrypt = function(encbuf, toprivkey) {
+  var kB = toprivkey.bn;
   var frompubkey = Pubkey().fromDER(encbuf.slice(0, 33));
   var R = frompubkey.point;
   var P = R.mul(kB);

lib/expmt/stealthmessage.js

@@ -63,13 +63,13 @@ StealthMessage.prototype.encrypt = function(ivbuf) {
     this.fromKeypair = Keypair().fromRandom();
   var receivePubkey = this.toStealthAddress.getReceivePubkey(this.fromKeypair);
   this.receiveAddress = Address().fromPubkey(receivePubkey);
-  this.encbuf = ECIES.encrypt(this.messagebuf, Keypair().set({pubkey: receivePubkey}), this.fromKeypair, ivbuf);
+  this.encbuf = ECIES.encrypt(this.messagebuf, receivePubkey, this.fromKeypair, ivbuf);
   return this;
 };
 
 StealthMessage.prototype.decrypt = function() {
   var receiveKeypair = this.toStealthkey.getReceiveKeypair(this.fromKeypair.pubkey);
-  this.messagebuf = ECIES.decrypt(this.encbuf, receiveKeypair);
+  this.messagebuf = ECIES.decrypt(this.encbuf, receiveKeypair.privkey);
   return this;
 };
 

test/ecies.js

@@ -22,12 +22,12 @@ describe('#ECIES', function() {
   describe('@encrypt', function() {
 
     it('should return a buffer', function() {
-      var encbuf = ECIES.encrypt(messagebuf, tokey, fromkey);
+      var encbuf = ECIES.encrypt(messagebuf, tokey.pubkey, fromkey);
       Buffer.isBuffer(encbuf).should.equal(true);
     });
 
     it('should return a buffer if fromkey is not present', function() {
-      var encbuf = ECIES.encrypt(messagebuf, tokey);
+      var encbuf = ECIES.encrypt(messagebuf, tokey.pubkey);
       Buffer.isBuffer(encbuf).should.equal(true);
     });
 
@@ -36,14 +36,14 @@ describe('#ECIES', function() {
   describe('@decrypt', function() {
 
     it('should decrypt that which was encrypted', function() {
-      var encbuf = ECIES.encrypt(messagebuf, tokey, fromkey);
-      var messagebuf2 = ECIES.decrypt(encbuf, tokey);
+      var encbuf = ECIES.encrypt(messagebuf, tokey.pubkey, fromkey);
+      var messagebuf2 = ECIES.decrypt(encbuf, tokey.privkey);
       messagebuf2.toString('hex').should.equal(messagebuf.toString('hex'));
     });
 
     it('should decrypt that which was encrypted if fromkeypair was randomly generated', function() {
-      var encbuf = ECIES.encrypt(messagebuf, tokey);
-      var messagebuf2 = ECIES.decrypt(encbuf, tokey);
+      var encbuf = ECIES.encrypt(messagebuf, tokey.pubkey);
+      var messagebuf2 = ECIES.decrypt(encbuf, tokey.privkey);
       messagebuf2.toString('hex').should.equal(messagebuf.toString('hex'));
     });