diff --git a/libi2pd/CryptoWorker.h b/libi2pd/CryptoWorker.h
new file mode 100644
index 00000000..f310032f
--- /dev/null
+++ b/libi2pd/CryptoWorker.h
@@ -0,0 +1,82 @@
+#ifndef CRYPTO_WORKER_H_
+#define CRYPTO_WORKER_H_
+
+#include <condition_variable>
+#include <mutex>
+#include <deque>
+#include <thread>
+#include <vector>
+#include <pair>
+#include <memory>
+
+namespace i2p
+{
+namespace worker
+{
+  template<typename Caller>
+  struct ThreadPool
+  {
+    typedef std::function<void(void)> ResultFunc;
+    typedef std::function<Result(void)> WorkFunc;
+    typedef std::pair<std::shared_ptr<Caller>, WorkFunc> Job;
+    typedef std::mutex mtx_t;
+    typedef std::unique_lock<mtx_t> lock_t;
+    typedef std::condition_variable cond_t;
+    ThreadPool(int workers)
+    {
+      stop = false;
+      if(workers > 0)
+      {
+        while(workers--)
+        {
+          threads.emplace_back([this] {
+              Job job;
+              for (;;)
+              {
+                {
+                  lock_t lock(this->queue_mutex);
+                  this->condition.wait(
+                    lock, [this] { return this->stop || !this->jobs.empty(); });
+                  if (this->stop && this->jobs.empty()) return;
+                  job = std::move(this->jobs.front());
+                  this->jobs.pop_front();
+                }
+              }
+              job.first->GetService().post(job.second());
+          });
+        }
+      }
+    };
+
+    void Offer(const Job & job)
+    {
+      {
+        lock_t lock(queue_mutex);
+        if (stop) return;
+        jobs.emplace_back(job);
+      }
+      condition.notify_one();
+    }
+
+    ~ThreadPool()
+    {
+      {
+        lock_t lock(queue_mutex);
+        stop = true;
+      }
+      condition.notify_all();
+      for(auto &t: threads) t.join();
+    }
+
+    std::vector<std::thread> threads;
+    std::deque<Job> jobs;
+    mtx_t queue_mutex;
+    cond_t condition;
+    bool stop;
+    
+  };
+}
+}
+
+
+#endif
diff --git a/libi2pd/NTCPSession.cpp b/libi2pd/NTCPSession.cpp
index 85c32743..653c24e5 100644
--- a/libi2pd/NTCPSession.cpp
+++ b/libi2pd/NTCPSession.cpp
@@ -171,27 +171,14 @@ namespace transport
 					return;
 				}
 			}
-#if ((__GNUC__ == 4) && (__GNUC_MINOR__ <= 7)) || defined(__NetBSD__)
-// due the bug in gcc 4.7. std::shared_future.get() is not const
-			if (!m_DHKeysPair)
-				m_DHKeysPair = transports.GetNextDHKeysPair ();
-			CreateAESKey (m_Establisher->phase1.pubKey);
-			SendPhase2 ();
-#else
 			// TODO: check for number of pending keys
 			auto s = shared_from_this ();
-			auto keyCreated = std::async (std::launch::async, [s] ()
-				{
+			m_Server.Work(s, [s]() -> std::function<void(void)> {
 					if (!s->m_DHKeysPair)
 						s->m_DHKeysPair = transports.GetNextDHKeysPair ();
 					s->CreateAESKey (s->m_Establisher->phase1.pubKey);
-				}).share ();
-			m_Server.GetService ().post ([s, keyCreated]()
-			{
-				keyCreated.get ();
-				s->SendPhase2 ();
+					return std::bind(&NTCPSession::SendPhase2, s);
 			});
-#endif
 		}
 	}
 
@@ -788,12 +775,14 @@ namespace transport
 	}
 
 //-----------------------------------------
-	NTCPServer::NTCPServer ():
+	NTCPServer::NTCPServer (int workers):
 		m_IsRunning (false), m_Thread (nullptr), m_Work (m_Service),
 		m_TerminationTimer (m_Service), m_NTCPAcceptor (nullptr), m_NTCPV6Acceptor (nullptr),
 		m_ProxyType(eNoProxy), m_Resolver(m_Service), m_ProxyEndpoint(nullptr),
 		m_SoftLimit(0), m_HardLimit(0)
 	{
+		if(workers <= 0) workers = 1;
+		m_CryptoPool = std::make_shared<Pool>(workers);
 	}
 
 	NTCPServer::~NTCPServer ()
diff --git a/libi2pd/NTCPSession.h b/libi2pd/NTCPSession.h
index b64f63aa..12ca92fc 100644
--- a/libi2pd/NTCPSession.h
+++ b/libi2pd/NTCPSession.h
@@ -12,6 +12,7 @@
 #include "RouterInfo.h"
 #include "I2NPProtocol.h"
 #include "TransportSession.h"
+#include "CryptoWorker.h"
 
 namespace i2p
 {
@@ -131,6 +132,8 @@ namespace transport
 	{
 		public:
 
+    typedef i2p::worker::ThreadPool<NTCPSession> Pool;
+
 			enum RemoteAddressType
 			{
 				eIP4Address,
@@ -146,7 +149,7 @@ namespace transport
 			};
 
 
-			NTCPServer ();
+			NTCPServer (int workers=4);
 			~NTCPServer ();
 
 			void Start ();
@@ -193,6 +196,11 @@ namespace transport
 			void ScheduleTermination ();
 			void HandleTerminationTimer (const boost::system::error_code& ecode);
 
+      void Work(std::shared_ptr<NTCPSession> conn, Pool::WorkFunc work)
+      {
+        m_CryptoPool->Offer({conn, work});
+      }
+    
 		private:
 
 			bool m_IsRunning;
@@ -210,6 +218,8 @@ namespace transport
 			boost::asio::ip::tcp::resolver m_Resolver;
 			boost::asio::ip::tcp::endpoint * m_ProxyEndpoint;
 
+      std::shared_ptr<Pool> m_CryptoPool;
+    
 			uint16_t m_SoftLimit, m_HardLimit;
 		public: