diff --git a/libi2pd/Crypto.cpp b/libi2pd/Crypto.cpp
index 8ba99a15..5e8ba855 100644
--- a/libi2pd/Crypto.cpp
+++ b/libi2pd/Crypto.cpp
@@ -8,6 +8,9 @@
 #include <openssl/crypto.h>
 #include "TunnelBase.h"
 #include <openssl/ssl.h>
+#include "I2PEndian.h"
+#include "ChaCha20.h"
+#include "Poly1305.h"
 #include "Log.h"
 #include "Crypto.h"
 
@@ -1057,6 +1060,32 @@ namespace crypto
 		}
 	}
 
+// AEAD/ChaCha20/Poly1305
+
+	size_t AEADChaCha20Poly1305Encrypt (const uint8_t * msg, size_t msgLen, const uint8_t * ad, size_t adLen, const uint8_t * key, const uint8_t * nonce, uint8_t * buf, size_t len)
+	{
+		if (msgLen + 16 < len) return 0;
+		// generate one time poly key
+		uint8_t polyKey[64];
+		memset(polyKey, 0, sizeof(polyKey));
+		chacha20 (polyKey, 64, nonce, key, 0);
+		// encrypt data		
+		memcpy (buf, msg, msgLen);
+		chacha20 (buf, msgLen, nonce, key, 1);
+		// create Poly1305 message
+		std::vector<uint8_t> polyMsg(adLen + msgLen + 16);
+		size_t offset = 0;	
+		memcpy (polyMsg.data (), ad, adLen); offset += adLen;
+		memcpy (polyMsg.data () + offset, buf, msgLen); offset += msgLen; // encrypted data
+		htole64buf (polyMsg.data () + offset, adLen); offset += 8;			
+		htole64buf (polyMsg.data () + offset, msgLen); offset += 8;
+		// calculate Poly1305 tag and write in after encrypted data		
+		Poly1305HMAC ((uint32_t *)(buf + msgLen), (uint32_t *)key, polyMsg.data (), offset);
+		return msgLen + 16;
+	}
+
+// init and terminate
+
 /*	std::vector <std::unique_ptr<std::mutex> >  m_OpenSSLMutexes;
 	static void OpensslLockingCallback(int mode, int type, const char * file, int line)
 	{
diff --git a/libi2pd/Crypto.h b/libi2pd/Crypto.h
index 859f2d97..0600c48c 100644
--- a/libi2pd/Crypto.h
+++ b/libi2pd/Crypto.h
@@ -252,6 +252,10 @@ namespace crypto
 			CBCDecryption m_LayerDecryption;
 	};
 
+// AEAD/ChaCha20/Poly1305
+	size_t AEADChaCha20Poly1305Encrypt (const uint8_t * msg, size_t msgLen, const uint8_t * ad, size_t adLen, const uint8_t * key, const uint8_t * nonce, uint8_t * buf, size_t len); 
+   	
+// init and terminate
 	void InitCrypto (bool precomputation);
 	void TerminateCrypto ();
 }
diff --git a/libi2pd/I2PEndian.h b/libi2pd/I2PEndian.h
index d2250768..0798f688 100644
--- a/libi2pd/I2PEndian.h
+++ b/libi2pd/I2PEndian.h
@@ -113,7 +113,20 @@ inline void htobe64buf(void *buf, uint64_t big64)
 	htobuf64(buf, htobe64(big64));
 }
 
+inline void htole16buf(void *buf, uint16_t big16)
+{
+	htobuf16(buf, htole16(big16));
+}
 
+inline void htole32buf(void *buf, uint32_t big32)
+{
+	htobuf32(buf, htole32(big32));
+}
+
+inline void htole64buf(void *buf, uint64_t big64)
+{
+	htobuf64(buf, htole64(big64));
+}
 
 #endif // I2PENDIAN_H__
 
diff --git a/libi2pd/NTCP2.cpp b/libi2pd/NTCP2.cpp
index 43ccc2dd..b3794354 100644
--- a/libi2pd/NTCP2.cpp
+++ b/libi2pd/NTCP2.cpp
@@ -6,8 +6,6 @@
 #include "I2PEndian.h"
 #include "Crypto.h"
 #include "Ed25519.h"
-#include "ChaCha20.h"
-#include "Poly1305.h"
 #include "NTCP2.h"
 
 namespace i2p
@@ -52,7 +50,7 @@ namespace transport
 		m_Server.GetService ().post (std::bind (&NTCP2Session::Terminate, shared_from_this ()));
 	}
 
-	bool NTCP2Session::KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived)
+	bool NTCP2Session::KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived, uint8_t * ad)
 	{
 		static const char protocolName[] = "Noise_XK_25519_ChaChaPoly_SHA256"; // 32 bytes
 		uint8_t h[64], ck[33];
@@ -63,7 +61,7 @@ namespace transport
 		SHA256 (h, 64, h); 
 		// h = SHA256(h || pub)
 		memcpy (h + 32, pub, 32); 
-		SHA256 (h, 64, h); 
+		SHA256 (h, 64, ad); 
 		// x25519 between rs and priv
 		uint8_t inputKeyMaterial[32];
 		BN_CTX * ctx = BN_CTX_new ();
@@ -106,8 +104,8 @@ namespace transport
 		encryption.SetIV (m_RemoteIV);
 		encryption.Encrypt (x, 32, m_SessionRequestBuffer);
 		// encryption key for next block
-		uint8_t key[32];
-		KeyDerivationFunction1 (m_RemoteStaticKey, x, key);
+		uint8_t key[32], ad[32];
+		KeyDerivationFunction1 (m_RemoteStaticKey, x, key, ad);
 		// fill options
 		uint8_t options[32]; // actual options size is 16 bytes
 		memset (options, 0, 16);
@@ -118,11 +116,9 @@ namespace transport
 		htobe32buf (options + 8, i2p::util::GetSecondsSinceEpoch ()); // tsA
 		// 4 bytes reserved
 		// sign and encrypt options			
-		i2p::crypto::Poly1305HMAC (((uint32_t *)options) + 4, (uint32_t *)key, options, 16); // calculate MAC first
 		uint8_t nonce[12];
 		memset (nonce, 0, 12); // set nonce to zero
-		i2p::crypto::chacha20 (options, 16, nonce, key); // then encrypt
-		memcpy (m_SessionRequestBuffer + 32, options, 32);
+		i2p::crypto::AEADChaCha20Poly1305Encrypt (options, 16, ad, 32, key, nonce, m_SessionRequestBuffer + 32, 32);
 		// send message
 		boost::asio::async_write (m_Socket, boost::asio::buffer (m_SessionRequestBuffer, paddingLength + 64), boost::asio::transfer_all (),
 			std::bind(&NTCP2Session::HandleSessionRequestSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));		
diff --git a/libi2pd/NTCP2.h b/libi2pd/NTCP2.h
index ca36d37b..8cdf6073 100644
--- a/libi2pd/NTCP2.h
+++ b/libi2pd/NTCP2.h
@@ -29,7 +29,7 @@ namespace transport
 
 		private:
 
-			bool KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived); // for SessionRequest
+			bool KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived, uint8_t * ad); // for SessionRequest
 			void CreateEphemeralKey (uint8_t * pub);
 			void SendSessionRequest ();