diff --git a/index.js b/index.js
index 555af11..88ba1d6 100644
--- a/index.js
+++ b/index.js
@@ -85,7 +85,7 @@ class HdKeyring extends SimpleKeyring {
   }
 
 
-  _getWalletForAccount (account, opts = {}) {
+  _getWalletForAccount (account) {
     const targetAddress = sigUtil.normalize(account)
 
     let wallet = this.wallets.find((w) => {
@@ -94,22 +94,14 @@ class HdKeyring extends SimpleKeyring {
               (sigUtil.normalize(address) === targetAddress))
     })
 
-    if (opts.withAppKeyOrigin) {
-      const privKey = wallet.getPrivateKey()
-      const appKeyOriginBuffer = Buffer.from(opts.withAppKeyOrigin, 'utf8')
-      const appKeyBuffer = Buffer.concat([privKey, appKeyOriginBuffer])
-      const appKeyPrivKey = ethUtil.keccak(appKeyBuffer, 256)
-      wallet = Wallet.fromPrivateKey(appKeyPrivKey)
-    }
-
     return wallet
   }
 
-  getPrivateKeyFor (address, opts = {}) {
+  getPrivateKeyFor (address) {
     if (!address) {
       throw new Error('Must specify address.');
     }
-    const wallet = this._getWalletForAccount(address, opts)
+    const wallet = this._getWalletForAccount(address)
     const privKey = ethUtil.toBuffer(wallet.getPrivateKey())
     return privKey;
   }
diff --git a/package.json b/package.json
index 99fb153..a5d70bf 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,7 @@
   "dependencies": {
     "bip39": "^2.2.0",
     "eth-sig-util": "^2.4.4",
-    "eth-simple-keyring": "^3.4.0",
+    "eth-simple-keyring": "^4.0.0",
     "ethereumjs-abi": "^0.6.5",
     "ethereumjs-util": "^5.1.1",
     "ethereumjs-wallet": "^0.6.0",
diff --git a/test/index.js b/test/index.js
index 32f0923..e8f3abb 100644
--- a/test/index.js
+++ b/test/index.js
@@ -385,63 +385,87 @@ describe('hd-keyring', function() {
     })
   })
 
-  describe('signing methods withAppKeyOrigin option', function () {
-    it('should signPersonalMessage with the expected key when passed a withAppKeyOrigin', function (done) {
+  describe('getAppKey', function () {
+    it('should return a private key custom to the provided app origin', async function () {
+      keyring = new HdKeyring({
+        mnemonic: sampleMnemonic,
+        numberOfAccounts: 1,
+      })
       const address = firstAcct
-      const message = '0x68656c6c6f20776f726c64'
+      const hexKey = await keyring.exportAccount(address)
 
-      const privateKeyBuffer = Buffer.from('8e82d2d74c50e5c8460f771d38a560ebe1151a9134c65a7e92b28ad0cfae7151', 'hex')
-      const expectedSig = sigUtil.personalSign(privateKeyBuffer, { data: message })
+      const appKey = await keyring.getAppKey(address, 'someapp.origin.io')
 
-      keyring.deserialize({
+      assert.notEqual(hexKey, appKey.toString('hex'))
+      assert(ethUtil.isValidPrivate(appKey))
+    })
+
+    it('should return different keyrings when provided different app origins', async function () {
+      keyring = new HdKeyring({
         mnemonic: sampleMnemonic,
         numberOfAccounts: 1,
       })
-      .then(() => {
-        return keyring.signPersonalMessage(address, message, {
-          withAppKeyOrigin: 'someapp.origin.io',
-        })
-      })
-      .then((sig) => {
-        assert.equal(sig, expectedSig, 'signed with app key')
-        done()
-      })
-      .catch((reason) => {
-        assert(!reason, reason.message)
-        done()
-      })
+      const address = firstAcct
+
+      const appKey1 = await keyring.getAppKey(address, 'someapp.origin.io')
+
+      assert(ethUtil.isValidPrivate(appKey1))
+
+      const appKey2 = await keyring.getAppKey(address, 'anotherapp.origin.io')
+
+      assert(ethUtil.isValidPrivate(appKey2))
+
+      assert.notEqual(appKey1.toString('hex'), appKey2.toString('hex'))
     })
 
-    it('should signTypedData with the expected key when passed a withAppKeyOrigin', function (done) {
+    it('should return the same keyring when called multiple times with the same params', async function () {
+      keyring = new HdKeyring({
+        mnemonic: sampleMnemonic,
+        numberOfAccounts: 1,
+      })
       const address = firstAcct
-      const typedData = {
-        types: {
-          EIP712Domain: []
-        },
-        domain: {},
-        primaryType: 'EIP712Domain',
-        message: {}
-      }
 
-      const privateKeyBuffer = Buffer.from('8e82d2d74c50e5c8460f771d38a560ebe1151a9134c65a7e92b28ad0cfae7151', 'hex')
-      const expectedSig = sigUtil.signTypedData(privateKeyBuffer, { data: typedData })
+      const appKey1 = await keyring.getAppKey(address, 'someapp.origin.io')
 
-      keyring.deserialize({
+      assert(ethUtil.isValidPrivate(appKey1))
+
+      const appKey2 = await keyring.getAppKey(address, 'someapp.origin.io')
+
+      assert(ethUtil.isValidPrivate(appKey2))
+
+      assert.equal(appKey1.toString('hex'), appKey2.toString('hex'))
+    })
+
+    it('should throw error if the provided origin is not a string', async function () {
+      keyring = new HdKeyring({
         mnemonic: sampleMnemonic,
-        numberOfAccounts: 1
-      }).then(() => {
-        return keyring.signTypedData_v3(address, typedData, {
-          withAppKeyOrigin: 'someapp.origin.io',
-        })
-      })
-      .then((sig) => {
-        assert.equal(sig, expectedSig, 'signed with app key')
-        done()
+        numberOfAccounts: 1,
       })
-      .catch((reason) => {
-        assert(!reason, reason.message)
-        done()
+      const address = firstAcct
+
+      try {
+        await keyring.getAppKey(address, [])
+      } catch (error) {
+        assert(error instanceof Error, 'Value thrown is not an error')
+        return
+      }
+      assert.fail('Should have thrown error')
+    })
+
+    it('should throw error if the provided origin is an empty string', async function () {
+      keyring = new HdKeyring({
+        mnemonic: sampleMnemonic,
+        numberOfAccounts: 1,
       })
+      const address = firstAcct
+
+      try {
+        await keyring.getAppKey(address, '')
+      } catch (error) {
+        assert(error instanceof Error, 'Value thrown is not an error')
+        return
+      }
+      assert.fail('Should have thrown error')
     })
   })
 })