diff --git a/backends/twitter/libtwitcurl/HMAC_SHA1.cpp b/backends/twitter/libtwitcurl/HMAC_SHA1.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..5382782e610612e3d9d029e18f533044c8e06508
--- /dev/null
+++ b/backends/twitter/libtwitcurl/HMAC_SHA1.cpp
@@ -0,0 +1,64 @@
+//******************************************************************************
+//* HMAC_SHA1.cpp : Implementation of HMAC SHA1 algorithm
+//*                 Comfort to RFC 2104
+//*
+//******************************************************************************
+#include "HMAC_SHA1.h"
+#include <iostream>
+#include <memory>
+
+
+void CHMAC_SHA1::HMAC_SHA1(BYTE *text, int text_len, BYTE *key, int key_len, BYTE *digest)
+{
+	memset(SHA1_Key, 0, SHA1_BLOCK_SIZE);
+
+	/* repeated 64 times for values in ipad and opad */
+	memset(m_ipad, 0x36, sizeof(m_ipad));
+	memset(m_opad, 0x5c, sizeof(m_opad));
+
+	/* STEP 1 */
+	if (key_len > SHA1_BLOCK_SIZE)
+	{
+		CSHA1::Reset();
+		CSHA1::Update((UINT_8 *)key, key_len);
+		CSHA1::Final();
+
+		CSHA1::GetHash((UINT_8 *)SHA1_Key);
+	}
+	else
+		memcpy(SHA1_Key, key, key_len);
+
+	/* STEP 2 */
+	for (size_t i=0; i<sizeof(m_ipad); i++)
+	{
+		m_ipad[i] ^= SHA1_Key[i];		
+	}
+
+	/* STEP 3 */
+	memcpy(AppendBuf1, m_ipad, sizeof(m_ipad));
+	memcpy(AppendBuf1 + sizeof(m_ipad), text, text_len);
+
+	/* STEP 4 */
+	CSHA1::Reset();
+	CSHA1::Update((UINT_8 *)AppendBuf1, sizeof(m_ipad) + text_len);
+	CSHA1::Final();
+
+	CSHA1::GetHash((UINT_8 *)szReport);
+
+	/* STEP 5 */
+	for (size_t j=0; j<sizeof(m_opad); j++)
+	{
+		m_opad[j] ^= SHA1_Key[j];
+	}
+
+	/* STEP 6 */
+	memcpy(AppendBuf2, m_opad, sizeof(m_opad));
+	memcpy(AppendBuf2 + sizeof(m_opad), szReport, SHA1_DIGEST_LENGTH);
+
+	/*STEP 7 */
+	CSHA1::Reset();
+	CSHA1::Update((UINT_8 *)AppendBuf2, sizeof(m_opad) + SHA1_DIGEST_LENGTH);
+	CSHA1::Final();
+
+	CSHA1::GetHash((UINT_8 *)digest);
+}