diff --git a/js/models/core/PrivateKey.js b/js/models/core/PrivateKey.js
index c1ea17561..9d9a7b009 100644
--- a/js/models/core/PrivateKey.js
+++ b/js/models/core/PrivateKey.js
@@ -10,45 +10,57 @@ var util        = bitcore.util;
 var PublicKeyRing  = require('./PublicKeyRing');
 
 function PrivateKey(opts) {
+  opts = opts || {};
   this.network = opts.networkName === 'testnet' ? 
     networks.testnet : networks.livenet;
   var init = opts.extendedPrivateKeyString || this.network.name;
-  this.BIP32 = opts.BIP32 || new BIP32(init);
+  this.bip = opts.BIP32 || new BIP32(init);
+  this.privateKeyCache = opts.privateKeyCache || {};
   this._calcId();
 };
 
 PrivateKey.prototype._calcId = function() {
-  this.id = util.ripe160(this.BIP32.extendedPublicKey).toString('hex');
+  this.id = util.ripe160(this.bip.extendedPublicKey).toString('hex');
 };
 
-PrivateKey.prototype.getBIP32 = function(index,isChange) {
-  if (typeof index === 'undefined') {
-    return this.BIP32;
-  }
-  return this.BIP32.derive( isChange ? 
-    PublicKeyRing.ChangeBranch(index):PublicKeyRing.PublicBranch(index) );
-};
-
-
-PrivateKey.fromObj = function(o) {
-  return new PrivateKey({
-    extendedPrivateKeyString: o.extendedPrivateKeyString,
-    networkName: o.networkName,
-  });
+PrivateKey.fromObj = function(obj) {
+  return new PrivateKey(obj);
 };
 
 PrivateKey.prototype.toObj = function() {
   return {
-    extendedPrivateKeyString: this.BIP32.extendedPrivateKeyString(),
+    extendedPrivateKeyString: this.getExtendedPrivateKeyString(),
     networkName: this.network.name,
+    privateKeyCache: this.privateKeyCache
   };
 };
 
+PrivateKey.prototype.getExtendedPublicKeyString = function() {
+  return this.bip.extendedPublicKeyString();
+};
+
+PrivateKey.prototype.getExtendedPrivateKeyString = function() {
+  return this.bip.extendedPrivateKeyString();
+};
+
+PrivateKey.prototype._getBIP32 = function(path) {
+  if (typeof path === 'undefined') {
+    return this.bip;
+  }
+  return this.bip.derive(path);
+};
+
 PrivateKey.prototype.get = function(index,isChange) {
-  var derivedBIP32 =  this.getBIP32(index,isChange);
+  var path = PublicKeyRing.Branch(index, isChange);
+  var pk = this.privateKeyCache[path];
+  if (!pk) {
+    var derivedBIP32 =  this._getBIP32(path);
+    pk = this.privateKeyCache[path] = derivedBIP32.eckey.private.toString('hex');
+  } else {
+    //console.log('cache hit!');
+  }
   var wk = new WalletKey({network: this.network});
-  var p = derivedBIP32.eckey.private.toString('hex');
-  wk.fromObj({priv: p});
+  wk.fromObj({priv: pk});
   return wk;
 };
 
diff --git a/js/models/core/PublicKeyRing.js b/js/models/core/PublicKeyRing.js
index 25feab792..25a31e6b9 100644
--- a/js/models/core/PublicKeyRing.js
+++ b/js/models/core/PublicKeyRing.js
@@ -40,12 +40,8 @@ function PublicKeyRing(opts) {
  *
  */
 
-PublicKeyRing.PublicBranch = function (index) {
-  return 'm/0/'+index;
-};
-
-PublicKeyRing.ChangeBranch = function (index) {
-  return 'm/1/'+index;
+PublicKeyRing.Branch = function (index, isChange) {
+  return 'm/'+(isChange?1:0)+'/'+index;
 };
 
 PublicKeyRing.fromObj = function (data) {
@@ -137,7 +133,7 @@ PublicKeyRing.prototype.getPubKeys = function (index, isChange) {
   var pubKeys = [];
   var l = this.copayersBIP32.length;
   for(var i=0; i<l; i++) {
-    var path = isChange ? PublicKeyRing.ChangeBranch(index) : PublicKeyRing.PublicBranch(index); 
+    var path = PublicKeyRing.Branch(index, isChange); 
     var bip32 = this.copayersBIP32[i].derive(path);
     pubKeys[i] = bip32.eckey.public;
   }
diff --git a/js/models/core/WalletFactory.js b/js/models/core/WalletFactory.js
index 2facf3b88..1b1c209e0 100644
--- a/js/models/core/WalletFactory.js
+++ b/js/models/core/WalletFactory.js
@@ -69,7 +69,7 @@ WalletFactory.prototype.read = function(walletId) {
   // JIC: Add our key
   try {
     w.publicKeyRing.addCopayer(
-      w.privateKey.getBIP32().extendedPublicKeyString()
+      w.privateKey.getExtendedPublicKeyString()
     );
   } catch (e) {
     this.log('NOT NECCESARY AN ERROR:', e); //TODO
@@ -94,7 +94,7 @@ WalletFactory.prototype.create = function(opts) {
     requiredCopayers: requiredCopayers,
     totalCopayers: totalCopayers,
   });
-  opts.publicKeyRing.addCopayer(opts.privateKey.getBIP32().extendedPublicKeyString());
+  opts.publicKeyRing.addCopayer(opts.privateKey.getExtendedPublicKeyString());
   this.log('\t### PublicKeyRing Initialized');
 
   opts.txProposals = opts.txProposals || new TxProposals({
@@ -110,7 +110,7 @@ WalletFactory.prototype.create = function(opts) {
   opts.spendUnconfirmed = opts.spendUnconfirmed || this.walletDefaults.spendUnconfirmed;
   opts.requiredCopayers = requiredCopayers;
   opts.totalCopayers = totalCopayers;
-  var w   = new Wallet(opts);
+  var w = new Wallet(opts);
   w.store();
   return w;
 };
@@ -139,7 +139,7 @@ WalletFactory.prototype.openRemote = function(peedId) {
     requiredCopayers: requiredCopayers,
     totalCopayers: totalCopayers,
   });
-  opts.publicKeyRing.addCopayer(opts.privateKey.getBIP32().extendedPublicKeyString());
+  opts.publicKeyRing.addCopayer(opts.privateKey.getExtendedPublicKeyString());
   this.log('\t### PublicKeyRing Initialized');
 
   opts.txProposals = opts.txProposals || new TxProposals({
diff --git a/test/index.html b/test/index.html
index 73440fcf6..d0fd279c4 100644
--- a/test/index.html
+++ b/test/index.html
@@ -19,6 +19,7 @@
     </script>
     <script src="test.API.js"></script>
     <script src="test.blockchain.Insight.js"></script>
+    <script src="test.performance.js"></script>
     <script src="test.PrivateKey.js"></script>
     <script src="test.PublicKeyRing.js"></script>
     <script src="test.storage.LocalPlain.js"></script>
diff --git a/test/test.PrivateKey.js b/test/test.PrivateKey.js
index 8875e7f3f..463f18054 100644
--- a/test/test.PrivateKey.js
+++ b/test/test.PrivateKey.js
@@ -24,8 +24,8 @@ describe('PrivateKey model', function() {
   it('should create an instance', function () {
     var w = new PrivateKey(config);
     should.exist(w);
-    should.exist(w.BIP32);
-    should.exist(w.BIP32.derive);
+    should.exist(w.bip);
+    should.exist(w.bip.derive);
   });
 
   it('should derive priv keys', function () {
@@ -76,15 +76,14 @@ describe('PrivateKey model', function() {
     var w1 = new PrivateKey(config);
     var w2 = PrivateKey.fromObj(w1.toObj());
 
-    w2.getBIP32().extendedPrivateKeyString().should.equal(w1.getBIP32().extendedPrivateKeyString());
-    w2.getBIP32().extendedPublicKeyString().should.equal(w1.getBIP32().extendedPublicKeyString());
+    w2.toObj().extendedPrivateKeyString.should.equal(w1.toObj().extendedPrivateKeyString);
     w2.id.should.equal(w1.id);
 
 
-    w2.getBIP32(1,1).extendedPrivateKeyString().should
-      .equal(w1.getBIP32(1,1).extendedPrivateKeyString());
-    w2.getBIP32(1,0).extendedPrivateKeyString().should
-      .equal(w1.getBIP32(1,0).extendedPrivateKeyString());
+    JSON.stringify(w2.get(1,1).storeObj()).should
+      .equal(JSON.stringify(w1.get(1,1).storeObj()));
+    JSON.stringify(w2.get(1,0).storeObj()).should
+      .equal(JSON.stringify(w1.get(1,0).storeObj()));
   });
  
 
diff --git a/test/test.TxProposals.js b/test/test.TxProposals.js
index aa120a17b..4c1f6c0bd 100644
--- a/test/test.TxProposals.js
+++ b/test/test.TxProposals.js
@@ -43,7 +43,7 @@ var createPKR = function (bip32s) {
   for(var i=0; i<5; i++) {
     if (bip32s) {
       var b=bip32s[i];
-      w.addCopayer(b?b.extendedPublicKeyString():null);
+      w.addCopayer(b?b.getExtendedPublicKeyString():null);
     }
     else 
       w.addCopayer();
@@ -110,7 +110,7 @@ describe('TxProposals model', function() {
       networkName: config.networkName,
     });
     var start = new Date().getTime();
-    var pkr=createPKR([priv.getBIP32()]);
+    var pkr=createPKR([priv]);
     var ts = Date.now();
     var isChange=0; 
     var index=0; 
@@ -150,7 +150,7 @@ describe('TxProposals model', function() {
     var ts = Date.now();
     var isChange=0; 
     var index=0; 
-    var pkr = createPKR([priv.getBIP32()]);
+    var pkr = createPKR([priv]);
     var opts = {remainderOut: { address: pkr.generateAddress(true).toString() }};
 
 
@@ -225,7 +225,7 @@ var _dumpChunks = function (scriptSig, label) {
    var ts = Date.now();
     var isChange=0; 
     var index=0; 
-    var pkr = createPKR([priv.getBIP32(), priv2.getBIP32()]);
+    var pkr = createPKR([priv, priv2]);
     var opts = {remainderOut: { address: pkr.generateAddress(true).toString() }};
 
     var w = new TxProposals({
@@ -325,7 +325,7 @@ var _dumpChunks = function (scriptSig, label) {
    var ts = Date.now();
     var isChange=0; 
     var index=0; 
-    var pkr = createPKR([priv.getBIP32(), priv2.getBIP32(),  priv3.getBIP32() ]);
+    var pkr = createPKR([priv, priv2,  priv3]);
     var opts = {remainderOut: { address: pkr.generateAddress(true).toString() }};
 
     var w = new TxProposals({
@@ -416,7 +416,7 @@ var _dumpChunks = function (scriptSig, label) {
   it('#toObj #fromObj roundtrip', function () {
 
     var priv = new PrivateKey(config);
-    var pkr = createPKR([priv.getBIP32()]);
+    var pkr = createPKR([priv]);
     var w = new TxProposals({
       walletId: 'qwerty',
       networkName: config.networkName,
diff --git a/test/test.Wallet.js b/test/test.Wallet.js
index 87423c7ee..f7eaad05a 100644
--- a/test/test.Wallet.js
+++ b/test/test.Wallet.js
@@ -41,7 +41,7 @@ describe('Wallet model', function() {
       requiredCopayers: c.requiredCopayers,
       totalCopayers: c.totalCopayers,
     });
-    c.publicKeyRing.addCopayer(c.privateKey.getBIP32().extendedPublicKeyString());
+    c.publicKeyRing.addCopayer(c.privateKey.getExtendedPublicKeyString());
 
     c.txProposals = new copay.TxProposals({
       networkName: c.networkName,
@@ -87,16 +87,16 @@ describe('Wallet model', function() {
   }
   ];
 
-  var createW2 = function (bip32s) {
+  var createW2 = function (privateKeys) {
     var w = createW();
     should.exist(w);
 
     var pkr =  w.publicKeyRing;
 
     for(var i=0; i<4; i++) {
-      if (bip32s) {
-        var b=bip32s[i];
-        pkr.addCopayer(b?b.extendedPublicKeyString():null);
+      if (privateKeys) {
+        var k=privateKeys[i];
+        pkr.addCopayer(k?k.getExtendedPublicKeyString():null);
       }
       else 
         pkr.addCopayer();
diff --git a/test/test.performance.js b/test/test.performance.js
new file mode 100644
index 000000000..ee552ad7f
--- /dev/null
+++ b/test/test.performance.js
@@ -0,0 +1,51 @@
+'use strict';
+
+var chai = chai || require('chai');
+var should = chai.should();
+
+var WebRTC = require('../js/models/network/WebRTC');
+var Insight = require('../js/models/blockchain/Insight');
+var FakeStorage = require('./mocks/FakeStorage');
+var PrivateKey = require('../js/models/core/PrivateKey');
+
+var WalletFactory = typeof copay === 'undefined' ? require('soop').load('../js/models/core/WalletFactory',{
+  Network: WebRTC,
+  Blockchain: Insight,
+  Storage: FakeStorage,
+}) : copay.WalletFactory;
+
+
+describe('Performance tests', function() {
+  var config = {
+    wallet: {
+      requiredCopayers: 1,
+      totalCopayers: 1,
+      spendUnconfirmed: 1,
+    },
+    networkName: 'testnet',
+  };
+
+  describe('PrivateKey', function() {
+    it('should optimize BIP32 private key gen time with cache', function() {
+      var k1 = new PrivateKey();
+      var generateN = 25;
+      var generated = [];
+      var start1 = new Date().getTime();
+      for (var i=0; i<generateN; i++) {
+        var k = JSON.stringify(k1.get(i, false).storeObj());
+        generated.push(k);
+      }
+      var delta1 = new Date().getTime() - start1;
+      var backup = k1.toObj();
+      var k2 = new PrivateKey(backup);
+      var start2 = new Date().getTime();
+      for (var i=0; i<generateN; i++) {
+        var k = JSON.stringify(k2.get(i, false).storeObj());
+        generated[i].should.equal(k);
+      }
+      var delta2 = new Date().getTime() - start2;
+      delta2.should.be.below(delta1);
+    });
+  });
+
+});