diff --git a/libraries/networking/src/NLPacket.cpp b/libraries/networking/src/NLPacket.cpp
index 5c5077691b..9df84e6abc 100644
--- a/libraries/networking/src/NLPacket.cpp
+++ b/libraries/networking/src/NLPacket.cpp
@@ -11,6 +11,8 @@
 
 #include "NLPacket.h"
 
+#include "HmacAuth.h"
+
 int NLPacket::localHeaderSize(PacketType type) {
     bool nonSourced = PacketTypeEnum::getNonSourcedPackets().contains(type);
     bool nonVerified = PacketTypeEnum::getNonVerifiedPackets().contains(type);
@@ -150,6 +152,14 @@ QByteArray NLPacket::verificationHashInHeader(const udt::Packet& packet) {
 }
 
 QByteArray NLPacket::hashForPacketAndSecret(const udt::Packet& packet, const QUuid& connectionSecret) {
+    HmacAuth hash;
+    int offset = Packet::totalHeaderSize(packet.isPartOfMessage()) + sizeof(PacketType) + sizeof(PacketVersion)
+        + NUM_BYTES_RFC4122_UUID + NUM_BYTES_MD5_HASH;
+    hash.setKey(connectionSecret);
+    hash.addData(packet.getData() + offset, packet.getDataSize() - offset);
+    auto hashResult(hash.result());
+    return QByteArray((const char*) hashResult.data(), (int) hashResult.size());
+    /*
     QCryptographicHash hash(QCryptographicHash::Md5);
     
     int offset = Packet::totalHeaderSize(packet.isPartOfMessage()) + sizeof(PacketType) + sizeof(PacketVersion)
@@ -161,6 +171,8 @@ QByteArray NLPacket::hashForPacketAndSecret(const udt::Packet& packet, const QUu
     
     // return the hash
     return hash.result();
+    */
+
 }
 
 void NLPacket::writeTypeAndVersion() {
diff --git a/libraries/shared/src/HmacAuth.cpp b/libraries/shared/src/HmacAuth.cpp
new file mode 100644
index 0000000000..6cc6835329
--- /dev/null
+++ b/libraries/shared/src/HmacAuth.cpp
@@ -0,0 +1,55 @@
+//
+// HmacAuth.cpp
+
+#include <openssl/hmac.h>
+
+#include "HmacAuth.h"
+
+#include <QUuid>
+
+HmacAuth::HmacAuth(AuthMethod authMethod)
+    : _hmacContext(new(HMAC_CTX))
+    , _authMethod(authMethod) {
+    HMAC_CTX_init(_hmacContext.get());
+}
+
+HmacAuth::~HmacAuth() {
+    HMAC_CTX_cleanup(_hmacContext.get());
+}
+
+bool HmacAuth::setKey(const char * keyValue, int keyLen) {
+    const EVP_MD * sslStruct = nullptr;
+
+    switch (_authMethod)
+    {
+    case SHA1:
+        sslStruct = EVP_sha1();
+        break;
+
+    case RIPEMD160:
+        sslStruct = EVP_ripemd160();
+        break;
+
+    default:
+        return false;
+    }
+
+    return (bool) HMAC_Init(_hmacContext.get(), keyValue, keyLen, sslStruct);
+}
+
+bool HmacAuth::setKey(const QUuid& uidKey) {
+    const QByteArray rfcBytes(uidKey.toRfc4122());
+    return setKey(rfcBytes.constData(), rfcBytes.length());
+}
+
+bool HmacAuth::addData(const char * data, int dataLen) {
+    return (bool) HMAC_Update(_hmacContext.get(), reinterpret_cast<const unsigned char*>(data), dataLen);
+}
+
+HmacAuth::HmacHash HmacAuth::result() {
+    HmacHash hashValue(EVP_MAX_MD_SIZE);
+    unsigned int  hashLen;
+    HMAC_Final(_hmacContext.get(), &hashValue[0], &hashLen);
+    hashValue.resize((size_t) hashLen);
+    return hashValue;
+}
diff --git a/libraries/shared/src/HmacAuth.h b/libraries/shared/src/HmacAuth.h
new file mode 100644
index 0000000000..9d90f5fb4d
--- /dev/null
+++ b/libraries/shared/src/HmacAuth.h
@@ -0,0 +1,32 @@
+//
+// HmacAuth.h
+// libraries/shared/src
+
+#ifndef hifi_HmacAuth_h
+#define hifi_HmacAuth_h
+
+#include <vector>
+#include <memory>
+
+struct hmac_ctx_st;
+class QUuid;
+
+class HmacAuth {
+public:
+    enum AuthMethod { SHA1, RIPEMD160 };
+    typedef std::vector<unsigned char> HmacHash;
+    
+    HmacAuth(AuthMethod authMethod = SHA1);
+    ~HmacAuth();
+
+    bool setKey(const char * keyValue, int keyLen);
+    bool setKey(const QUuid& uidKey);
+    bool addData(const char * data, int dataLen);
+    HmacHash result();
+
+private:
+    std::unique_ptr<hmac_ctx_st> _hmacContext;
+    AuthMethod _authMethod { SHA1 };
+};
+
+#endif  // hifi_HmacAuth_h