diff --git a/libdevcrypto/Common.cpp b/libdevcrypto/Common.cpp
index 21b854ca3..7e3c403cd 100644
--- a/libdevcrypto/Common.cpp
+++ b/libdevcrypto/Common.cpp
@@ -94,24 +94,23 @@ bool dev::decryptSym(Secret const& _k, bytesConstRef _cipher, bytes& o_plain)
 	return decrypt(_k, _cipher, o_plain);
 }
 
-h256 dev::encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher)
+h128 dev::encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher)
 {
-	auto iv = Nonce::get();
+	h128 iv(Nonce::get());
 	return encryptSymNoAuth(_k, _plain, o_cipher, iv);
 }
 
-h256 dev::encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher, h256 const& _iv)
+h128 dev::encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher, h128 const& _iv)
 {
 	const int c_aesBlockLen = 16;
-	o_cipher.resize(_plain.size() + (c_aesBlockLen - (_plain.size() % c_aesBlockLen)) % c_aesBlockLen);
+	size_t extraBytes = _plain.size() % c_aesBlockLen;
+	size_t trimmedSize = _plain.size() - extraBytes;
+	size_t paddedSize = _plain.size() + ((16 - extraBytes) % 16);
+	o_cipher.resize(paddedSize);
 	
-	bytes underflowBytes(0);
-	auto size = _plain.size() - (_plain.size() % c_aesBlockLen);
-	if (o_cipher.size() > _plain.size())
-	{
-		underflowBytes.resize(c_aesBlockLen);
-		_plain.cropped(size, _plain.size() - size).copyTo(&underflowBytes);
-	}
+	bytes underflowBytes(16);
+	if (o_cipher.size() != _plain.size())
+		_plain.cropped(trimmedSize, extraBytes).copyTo(&underflowBytes);
 	
 	const int c_aesKeyLen = 32;
 	SecByteBlock key(_k.data(), c_aesKeyLen);
@@ -119,28 +118,28 @@ h256 dev::encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_ciph
 	{
 		CTR_Mode<AES>::Encryption e;
 		e.SetKeyWithIV(key, key.size(), _iv.data());
-		if (size)
-			e.ProcessData(o_cipher.data(), _plain.data(), _plain.size());
-		if (underflowBytes.size())
-			e.ProcessData(o_cipher.data(), underflowBytes.data(), underflowBytes.size());
+		if (trimmedSize)
+			e.ProcessData(o_cipher.data(), _plain.data(), trimmedSize);
+		if (extraBytes)
+			e.ProcessData(o_cipher.data() + trimmedSize, underflowBytes.data(), underflowBytes.size());
 		return _iv;
 	}
 	catch(CryptoPP::Exception& e)
 	{
 		cerr << e.what() << endl;
 		o_cipher.resize(0);
-		return h256();
+		return h128();
 	}
 }
 
-bool dev::decryptSymNoAuth(Secret const& _k, h256 const& _iv, bytesConstRef _cipher, bytes& o_plaintext)
+bool dev::decryptSymNoAuth(Secret const& _k, h128 const& _iv, bytesConstRef _cipher, bytes& o_plaintext)
 {
-	const int c_aesKeyLen = 32;
 	const int c_aesBlockLen = 16;
 	asserts(_cipher.size() % c_aesBlockLen == 0);
 	o_plaintext.resize(_cipher.size());
-	SecByteBlock key(_k.data(), c_aesKeyLen);
 	
+	const int c_aesKeyLen = 32;
+	SecByteBlock key(_k.data(), c_aesKeyLen);
 	try
 	{
 		CTR_Mode<AES>::Decryption d;
diff --git a/libdevcrypto/Common.h b/libdevcrypto/Common.h
index 9c33c4bb3..92a13f9a5 100644
--- a/libdevcrypto/Common.h
+++ b/libdevcrypto/Common.h
@@ -96,9 +96,9 @@ void encryptSym(Secret const& _k, bytesConstRef _plain, bytes& o_cipher);
 /// Symmetric decryption.
 bool decryptSym(Secret const& _k, bytesConstRef _cipher, bytes& o_plaintext);
 
-h256 encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher);
-h256 encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher, h256 const& _iv);
-bool decryptSymNoAuth(Secret const& _k, h256 const& _iv, bytesConstRef _cipher, bytes& o_plaintext);
+h128 encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher);
+h128 encryptSymNoAuth(Secret const& _k, bytesConstRef _plain, bytes& o_cipher, h128 const& _iv);
+bool decryptSymNoAuth(Secret const& _k, h128 const& _iv, bytesConstRef _cipher, bytes& o_plaintext);
 
 /// Recovers Public key from signed message hash.
 Public recover(Signature const& _sig, h256 const& _hash);
diff --git a/libdevcrypto/CryptoPP.cpp b/libdevcrypto/CryptoPP.cpp
index d9ccb3a35..47061d6d0 100644
--- a/libdevcrypto/CryptoPP.cpp
+++ b/libdevcrypto/CryptoPP.cpp
@@ -19,8 +19,9 @@
  * @date 2014
  */
 
-#include "CryptoPP.h"
 #include <libdevcore/Guards.h>
+#include "ECDHE.h"
+#include "CryptoPP.h"
 
 using namespace std;
 using namespace dev;
@@ -31,6 +32,113 @@ static_assert(dev::Secret::size == 32, "Secret key must be 32 bytes.");
 static_assert(dev::Public::size == 64, "Public key must be 64 bytes.");
 static_assert(dev::Signature::size == 65, "Signature must be 65 bytes.");
 
+bytes Secp256k1::eciesKDF(Secret _z, bytes _s1, unsigned kdBitLen)
+{
+	// similar to go ecies implementation
+	
+	if (!_s1.size())
+	{
+		_s1.resize(1);
+		asserts(_s1[0] == 0);
+	}
+	
+	// for sha3, hash.blocksize is 1088 bits, but this might really be digest size
+	auto reps = ((kdBitLen + 7) * 8) / (32 * 8);
+	bytes ctr({0, 0, 0, 1});
+	bytes k;
+	CryptoPP::SHA256 ctx;
+	while (reps--)
+	{
+		ctx.Update(ctr.data(), ctr.size());
+		ctx.Update(_z.data(), Secret::size);
+		ctx.Update(_s1.data(), _s1.size());
+		// append hash to k
+		bytes digest(32);
+		ctx.Final(digest.data());
+		ctx.Restart();
+		
+		k.reserve(k.size() + h256::size);
+		move(digest.begin(), digest.end(), back_inserter(k));
+		
+		if (ctr[3]++ && ctr[3] != 0) {
+			continue;
+		} else if (ctr[2]++ && ctr[2] != 0) {
+			continue;
+		} else if (ctr[1]++ && ctr[1] != 0) {
+			continue;
+		} else
+			ctr[0]++;
+	}
+	
+	k.resize(kdBitLen / 8);
+	return move(k);
+}
+
+void Secp256k1::encryptECIES(Public const& _k, bytes& io_cipher)
+{
+	// similar to go ecies implementation
+	// todo: s1/s2/tag
+	
+	auto r = KeyPair::create();
+	h256 z;
+	ecdh::agree(r.sec(), _k, z);
+	auto key = eciesKDF(z, bytes(), 512);
+	bytesConstRef eKey = bytesConstRef(&key).cropped(0, 32);
+	bytesRef mKey = bytesRef(&key).cropped(32, 32);
+	sha3(mKey, mKey);
+	
+	bytes cipherText;
+	encryptSymNoAuth(*(Secret*)eKey.data(), bytesConstRef(&io_cipher), cipherText, h128());
+	if (!cipherText.size())
+		return;
+	
+//	d := messageTag(params.Hash, Km, em, s2)
+//	copy(ct[len(Rb)+len(em):], d)
+	
+	bytes msg(1 + Public::size + cipherText.size() + 32);
+	msg[0] = 0x04;
+	r.pub().ref().copyTo(bytesRef(&msg).cropped(1, Public::size));
+	bytesRef msgCipherRef = bytesRef(&msg).cropped(1 + Public::size, cipherText.size());
+	bytesConstRef(&cipherText).copyTo(msgCipherRef);
+	
+	io_cipher.resize(msg.size());
+	io_cipher.swap(msg);
+}
+
+void eciesMessageTag()
+{
+	
+}
+
+void Secp256k1::decryptECIES(Secret const& _k, bytes& io_text)
+{
+	// similar to go ecies implementation
+	// todo: s1/s2
+
+	// io_cipher[0] must be 2, 3, or 4, else invalidpublickey
+	if (io_text[0] < 2 || io_text[0] > 4)
+		// invalid message: publickey
+		return;
+	
+	if (io_text.size() < (1 + Public::size + h256::size + 1))
+		// invalid message: length
+		return;
+
+	h256 z;
+	ecdh::agree(_k, *(Public*)(io_text.data()+1), z);
+	auto key = eciesKDF(z, bytes(), 512);
+	bytesConstRef eKey = bytesConstRef(&key).cropped(0, 32);
+	bytesRef mKey = bytesRef(&key).cropped(32, 32);
+	sha3(mKey, mKey);
+	
+	bytes plain;
+	size_t cipherLen = io_text.size() - 1 - Public::size - h256::size;
+	bytesConstRef cipher(io_text.data() + 1 + Public::size, cipherLen);
+	decryptSymNoAuth(*(Secret*)eKey.data(), h128(), cipher, plain);
+	io_text.resize(plain.size());
+	io_text.swap(plain);
+}
+
 void Secp256k1::encrypt(Public const& _k, bytes& io_cipher)
 {
 	ECIES<ECP>::Encryptor e;
diff --git a/libdevcrypto/CryptoPP.h b/libdevcrypto/CryptoPP.h
index fa9d92aa1..3464606f6 100644
--- a/libdevcrypto/CryptoPP.h
+++ b/libdevcrypto/CryptoPP.h
@@ -81,6 +81,15 @@ public:
 	/// Decrypts text (replace input).
 	void decrypt(Secret const& _k, bytes& io_text);
 	
+	/// Temporary; to replace encrypt once interop w/go is passing.
+	void encryptECIES(Public const& _k, bytes& io_cipher);
+
+	/// Temporary; to replace decrypt once interop w/go is passing.
+	void decryptECIES(Secret const& _k, bytes& io_text);
+	
+	/// Key derivation function used by ECIES.
+	bytes eciesKDF(Secret _z, bytes _s1, unsigned kdBitLen = 256);
+	
 	/// @returns siganture of message.
 	Signature sign(Secret const& _k, bytesConstRef _message);
 	
diff --git a/libp2p/Host.cpp b/libp2p/Host.cpp
index 669d1eb0c..8d9994003 100644
--- a/libp2p/Host.cpp
+++ b/libp2p/Host.cpp
@@ -394,12 +394,12 @@ void PeerHandshake::transition(boost::system::error_code _ech)
 		{
 			clog(NetConnect) << "devp2p.connect.egress sending auth";
 			// egress: tx auth
-			asserts(remote);
+			asserts((bool)remote);
 			auth.resize(Signature::size + h256::size + Public::size + h256::size + 1);
-			bytesConstRef sig(&auth[0], Signature::size);
-			bytesConstRef hepubk(&auth[Signature::size], h256::size);
-			bytesConstRef pubk(&auth[Signature::size + h256::size], Public::size);
-			bytesConstRef nonce(&auth[Signature::size + h256::size + Public::size], h256::size);
+			bytesRef sig(&auth[0], Signature::size);
+			bytesRef hepubk(&auth[Signature::size], h256::size);
+			bytesRef pubk(&auth[Signature::size + h256::size], Public::size);
+			bytesRef nonce(&auth[Signature::size + h256::size + Public::size], h256::size);
 			
 			// E(remote-pubk, S(ecdhe-random, ecdh-shared-secret^nonce) || H(ecdhe-random-pubk) || pubk || nonce || 0x0)
 			crypto::ecdh::agree(host->m_alias.sec(), remote, ss);
@@ -469,8 +469,8 @@ void PeerHandshake::transition(boost::system::error_code _ech)
 			clog(NetConnect) << "devp2p.connect.ingress sending ack";
 			// ingress: tx ack
 			ack.resize(Public::size + h256::size + 1);
-			bytesConstRef epubk(&ack[0], Public::size);
-			bytesConstRef nonce(&ack[Public::size], h256::size);
+			bytesRef epubk(&ack[0], Public::size);
+			bytesRef nonce(&ack[Public::size], h256::size);
 			ecdhe.pubkey().ref().copyTo(epubk);
 			this->nonce.ref().copyTo(nonce);
 			ack[ack.size() - 1] = 0x0;
@@ -489,7 +489,7 @@ void PeerHandshake::transition(boost::system::error_code _ech)
 			clog(NetConnect) << "devp2p.connect.ingress sending magic sequence";
 		PeerSecrets* k = new PeerSecrets;
 		bytes keyMaterialBytes(512);
-		bytesConstRef keyMaterial(&keyMaterialBytes);
+		bytesRef keyMaterial(&keyMaterialBytes);
 
 		ecdhe.agree(remoteEphemeral, ess);
 		ess.ref().copyTo(keyMaterial.cropped(0, h256::size));
@@ -521,10 +521,10 @@ void PeerHandshake::transition(boost::system::error_code _ech)
 		// This test will be replaced with protocol-capabilities information (was Hello packet)
 		// TESTING: send encrypt magic sequence
 		bytes magic {0x22,0x40,0x08,0x91};
-		encryptSymNoAuth(k->encryptK, &magic, k->magicCipherAndMac, h256());
+		encryptSymNoAuth(k->encryptK, &magic, k->magicCipherAndMac, h128());
 		k->magicCipherAndMac.resize(k->magicCipherAndMac.size() + 32);
 		sha3mac(k->egressMac.ref(), &magic, k->egressMac.ref());
-		k->egressMac.ref().copyTo(bytesConstRef(&k->magicCipherAndMac).cropped(k->magicCipherAndMac.size() - 32, 32));
+		k->egressMac.ref().copyTo(bytesRef(&k->magicCipherAndMac).cropped(k->magicCipherAndMac.size() - 32, 32));
 		
 		clog(NetConnect) << "devp2p.connect.egress txrx magic sequence";
 		k->recvdMagicCipherAndMac.resize(k->magicCipherAndMac.size());
@@ -554,7 +554,7 @@ void PeerHandshake::transition(boost::system::error_code _ech)
 				
 				/// capabilities handshake (encrypted magic sequence is placeholder)
 				bytes decryptedMagic;
-				decryptSymNoAuth(k->encryptK, h256(), &k->recvdMagicCipherAndMac, decryptedMagic);
+				decryptSymNoAuth(k->encryptK, h128(), &k->recvdMagicCipherAndMac, decryptedMagic);
 				if (decryptedMagic[0] == 0x22 && decryptedMagic[1] == 0x40 && decryptedMagic[2] == 0x08 && decryptedMagic[3] == 0x91)
 				{
 					shared_ptr<Peer> p;
diff --git a/test/crypto.cpp b/test/crypto.cpp
index 5dec3dd6d..56fb8a51c 100644
--- a/test/crypto.cpp
+++ b/test/crypto.cpp
@@ -228,6 +228,51 @@ BOOST_AUTO_TEST_CASE(cryptopp_ecdsa_sipaseckp256k1)
 	}
 }
 
+BOOST_AUTO_TEST_CASE(ecies_kdf)
+{
+	KeyPair local = KeyPair::create();
+	KeyPair remote = KeyPair::create();
+	// nonce
+	Secret z1;
+	ecdh::agree(local.sec(), remote.pub(), z1);
+	auto key1 = s_secp256k1.eciesKDF(z1, bytes(), 512);
+	bytesConstRef eKey1 = bytesConstRef(&key1).cropped(0, 32);
+	bytesRef mKey1 = bytesRef(&key1).cropped(32, 32);
+	sha3(mKey1, mKey1);
+	
+	Secret z2;
+	ecdh::agree(remote.sec(), local.pub(), z2);
+	auto key2 = s_secp256k1.eciesKDF(z2, bytes(), 512);
+	bytesConstRef eKey2 = bytesConstRef(&key2).cropped(0, 32);
+	bytesRef mKey2 = bytesRef(&key2).cropped(32, 32);
+	sha3(mKey2, mKey2);
+	
+	BOOST_REQUIRE(eKey1.toBytes() == eKey2.toBytes());
+	BOOST_REQUIRE(mKey1.toBytes() == mKey2.toBytes());
+	
+	BOOST_REQUIRE((u256)h256(z1) > 0);
+	BOOST_REQUIRE(z1 == z2);
+	
+	BOOST_REQUIRE(key1.size() > 0 && ((u512)h512(key1)) > 0);
+	BOOST_REQUIRE(key1 == key2);
+}
+
+BOOST_AUTO_TEST_CASE(ecies_standard)
+{
+	KeyPair k = KeyPair::create();
+	
+	string message("Now is the time for all good persons to come to the aid of humanity.");
+	string original = message;
+	bytes b = asBytes(message);
+	
+	s_secp256k1.encryptECIES(k.pub(), b);
+	BOOST_REQUIRE(b != asBytes(original));
+	BOOST_REQUIRE(b.size() > 0 && ((u128)h128(b)) > 0);
+	
+	s_secp256k1.decryptECIES(k.sec(), b);
+	BOOST_REQUIRE(bytesConstRef(&b).cropped(0, original.size()).toBytes() == asBytes(original));
+}
+
 BOOST_AUTO_TEST_CASE(ecies_eckeypair)
 {
 	KeyPair k = KeyPair::create();
@@ -341,10 +386,10 @@ BOOST_AUTO_TEST_CASE(handshakeNew)
 	bytes auth(Signature::size + h256::size + Public::size + h256::size + 1);
 	Secret ssA;
 	{
-		bytesConstRef sig(&auth[0], Signature::size);
-		bytesConstRef hepubk(&auth[Signature::size], h256::size);
-		bytesConstRef pubk(&auth[Signature::size + h256::size], Public::size);
-		bytesConstRef nonce(&auth[Signature::size + h256::size + Public::size], h256::size);
+		bytesRef sig(&auth[0], Signature::size);
+		bytesRef hepubk(&auth[Signature::size], h256::size);
+		bytesRef pubk(&auth[Signature::size + h256::size], Public::size);
+		bytesRef nonce(&auth[Signature::size + h256::size + Public::size], h256::size);
 		
 		crypto::ecdh::agree(nodeA.sec(), nodeB.pub(), ssA);
 		sign(eA.seckey(), ssA ^ nonceA).ref().copyTo(sig);
@@ -371,8 +416,8 @@ BOOST_AUTO_TEST_CASE(handshakeNew)
 		bytesConstRef pubk(&authdecrypted[Signature::size + h256::size], Public::size);
 		pubk.copyTo(node.ref());
 		
-		bytesConstRef epubk(&ack[0], Public::size);
-		bytesConstRef nonce(&ack[Public::size], h256::size);
+		bytesRef epubk(&ack[0], Public::size);
+		bytesRef nonce(&ack[Public::size], h256::size);
 		
 		eB.pubkey().ref().copyTo(epubk);
 		nonceB.ref().copyTo(nonce);
@@ -398,7 +443,7 @@ BOOST_AUTO_TEST_CASE(handshakeNew)
 		bytesConstRef ackRef(&ackdecrypted);
 		Public eBAck;
 		h256 nonceBAck;
-		ackRef.cropped(0, Public::size).copyTo(bytesConstRef(eBAck.data(), Public::size));
+		ackRef.cropped(0, Public::size).copyTo(bytesRef(eBAck.data(), Public::size));
 		ackRef.cropped(Public::size, h256::size).copyTo(nonceBAck.ref());
 		BOOST_REQUIRE_EQUAL(eBAck, eB.pubkey());
 		BOOST_REQUIRE_EQUAL(nonceBAck, nonceB);
@@ -406,7 +451,7 @@ BOOST_AUTO_TEST_CASE(handshakeNew)
 		// TODO: export ess and require equal to b
 		
 		bytes keyMaterialBytes(512);
-		bytesConstRef keyMaterial(&keyMaterialBytes);
+		bytesRef keyMaterial(&keyMaterialBytes);
 		
 		h256 ess;
 		// todo: ecdh-agree should be able to output bytes
@@ -473,7 +518,7 @@ BOOST_AUTO_TEST_CASE(handshakeNew)
 		BOOST_REQUIRE_EQUAL(eAAuth, eA.pubkey());
 		
 		bytes keyMaterialBytes(512);
-		bytesConstRef keyMaterial(&keyMaterialBytes);
+		bytesRef keyMaterial(&keyMaterialBytes);
 		
 		h256 ess;
 		// todo: ecdh-agree should be able to output bytes
@@ -519,24 +564,29 @@ BOOST_AUTO_TEST_CASE(ecdhe_aes128_ctr_sha3mac)
 	
 }
 
-BOOST_AUTO_TEST_CASE(crypto_rlpxwire)
+BOOST_AUTO_TEST_CASE(ecies_aes128_ctr_unaligned)
 {
 	Secret encryptK(sha3("..."));
 	h256 egressMac(sha3("+++"));
 	// TESTING: send encrypt magic sequence
 	bytes magic {0x22,0x40,0x08,0x91};
 	bytes magicCipherAndMac;
-	encryptSymNoAuth(encryptK, &magic, magicCipherAndMac, h256());
+	encryptSymNoAuth(encryptK, &magic, magicCipherAndMac, h128());
+	
 	magicCipherAndMac.resize(magicCipherAndMac.size() + 32);
 	sha3mac(egressMac.ref(), &magic, egressMac.ref());
-	egressMac.ref().copyTo(bytesConstRef(&magicCipherAndMac).cropped(magicCipherAndMac.size() - 32, 32));
+	egressMac.ref().copyTo(bytesRef(&magicCipherAndMac).cropped(magicCipherAndMac.size() - 32, 32));
 	
 	bytes plaintext;
 	bytesConstRef cipher(&magicCipherAndMac[0], magicCipherAndMac.size() - 32);
-	decryptSymNoAuth(encryptK, h256(), cipher, plaintext);
+	decryptSymNoAuth(encryptK, h128(), cipher, plaintext);
+	
+	plaintext.resize(magic.size());
+	BOOST_REQUIRE(plaintext.size() > 0);
+	BOOST_REQUIRE(magic == plaintext);
 }
 
-BOOST_AUTO_TEST_CASE(crypto_aes128_ctr)
+BOOST_AUTO_TEST_CASE(ecies_aes128_ctr)
 {
 	Secret k(sha3("0xAAAA"));
 	string m = "AAAAAAAAAAAAAAAA";