diff --git a/integrity_algo.cpp b/integrity_algo.cpp
index b765e06..16d0863 100644
--- a/integrity_algo.cpp
+++ b/integrity_algo.cpp
@@ -25,6 +25,47 @@
     authCodeLength = authLength;
 }
 
+Buffer AlgoSHA1::generateHMAC(const uint8_t* input, const size_t len) const
+{
+    Buffer output(SHA_DIGEST_LENGTH);
+    unsigned int mdLen = 0;
+
+    if (HMAC(EVP_sha1(), K1.data(), K1.size(), input, len,
+             output.data(), &mdLen) == NULL)
+    {
+        throw std::runtime_error("Generating integrity data failed");
+    }
+
+    // HMAC generates Message Digest to the size of SHA_DIGEST_LENGTH, the
+    // AuthCode field length is based on the integrity algorithm. So we are
+    // interested only in the AuthCode field length of the generated Message
+    // digest.
+    output.resize(authCodeLength);
+
+    return output;
+}
+
+bool AlgoSHA1::verifyIntegrityData(const Buffer& packet,
+                                   const size_t length,
+                                   Buffer::const_iterator integrityData) const
+{
+
+    auto output = generateHMAC(
+            packet.data() + message::parser::RMCP_SESSION_HEADER_SIZE,
+            length);
+
+    // Verify if the generated integrity data for the packet and the received
+    // integrity data matches.
+    return (std::equal(output.begin(), output.end(), integrityData));
+}
+
+Buffer AlgoSHA1::generateIntegrityData(const Buffer& packet) const
+{
+    return generateHMAC(
+            packet.data() + message::parser::RMCP_SESSION_HEADER_SIZE,
+            packet.size() - message::parser::RMCP_SESSION_HEADER_SIZE);
+}
+
 }// namespace integrity
 
 }// namespace cipher