// HMAC_hash(MAC_write_secret, seq_num + TLSCompressed.type +
// TLSCompressed.version + TLSCompressed.length +
// TLSCompressed.fragment));
/// <summary>
/// Computes the TLS 1.0 MD5 HMAC for a record.
/// </summary>
/// <param name="secret">The secret to use for the HMAC calculation.</param>
/// <param name="contentType">The TLS record content type.</param>
/// <param name="sequenceNumber">The sequence number of the fragment.</param>
/// <param name="fragment">The data sent.</param>
/// <returns>The 16 byte HMAC hash.</returns>
public static byte[] ComputeTlsMD5Hmac(byte[] secret, byte contentType, long sequenceNumber, byte[] fragment)
{
_HmacMd5.Key = secret;
return(_HmacMd5.ComputeHash(
ByteUtilities.ConcatBytes(
BitConverter.GetBytes(IPAddress.HostToNetworkOrder(sequenceNumber)),
new [] { contentType },
new byte[] { 3, 1 }, // version
BitConverter.GetBytes(IPAddress.HostToNetworkOrder((short)fragment.Length)),
fragment)));
}
private void btnGenerateHmac_Click(object sender, EventArgs e)
{
try
{
byte[] keyBytes = txtHmacKeyString.Text.ToAsciiBytes();
txtHmacKeyAsciiBytes.Text = keyBytes.ToDisplayByteString();
byte[] dataBytes = txtHmacDataString.Text.ToAsciiBytes();
txtHmacDataAsciiBytes.Text = dataBytes.ToDisplayByteString();
const int blockSize = 64;
Func <byte, byte[]> getPad = padByte => Enumerable.Range(1, blockSize).Select(n => padByte).ToArray();
// SHA-1
byte[] sha1Key = keyBytes.Length > blockSize?Hasher.ComputeSHA1Hash(keyBytes) : keyBytes;
byte[] sha1Opad = getPad(0x5c);
txtHmacSha1Opad.Text = sha1Opad.ToDisplayByteString();
byte[] sha1KeyXorOpad = sha1Key.Xor(sha1Opad);
txtHmacSha1KeyXorOpad.Text = sha1KeyXorOpad.ToDisplayByteString();
byte[] sha1Ipad = getPad(0x36);
txtHmacSha1IpadBytes.Text = sha1Ipad.ToDisplayByteString();
byte[] sha1KeyXorIpad = sha1Key.Xor(sha1Ipad);
txtHmacSha1KeyXorIpad.Text = sha1KeyXorIpad.ToDisplayByteString();
byte[] sha1TotalInnerToHash = ByteUtilities.ConcatBytes(sha1KeyXorIpad, dataBytes);
byte[] sha1InnerHash = Hasher.ComputeSHA1Hash(sha1TotalInnerToHash);
txtHmacSha1InnerHash.Text = sha1InnerHash.ToDisplayByteString();
byte[] sha1Hmac = Hasher.ComputeSHA1Hash(ByteUtilities.ConcatBytes(sha1KeyXorOpad, sha1InnerHash));
byte[] sha1ExpectedHmac = Hasher.ComputeSHA1Hmac(keyBytes, dataBytes);
Debug.Assert(ByteUtilities.AreEqual(sha1ExpectedHmac, sha1Hmac));
txtHmacSha1Result.Text = sha1Hmac.ToDisplayByteString();
// MD5
byte[] md5Key = keyBytes.Length > blockSize?Hasher.ComputeMD5(keyBytes) : keyBytes;
byte[] md5Opad = getPad(0x5c);
txtHmacMd5Opad.Text = md5Opad.ToDisplayByteString();
byte[] md5KeyXorOpad = md5Key.Xor(md5Opad);
txtHmacMd5KeyXorOpad.Text = md5KeyXorOpad.ToDisplayByteString();
byte[] md5Ipad = getPad(0x36);
txtHmacMd5IpadBytes.Text = md5Ipad.ToDisplayByteString();
byte[] md5KeyXorIpad = md5Key.Xor(md5Ipad);
txtHmacMd5KeyXorIpad.Text = md5KeyXorIpad.ToDisplayByteString();
byte[] md5TotalInnerToHash = ByteUtilities.ConcatBytes(md5KeyXorIpad, dataBytes);
byte[] md5InnerHash = Hasher.ComputeMD5(md5TotalInnerToHash);
txtHmacMd5InnerHash.Text = md5InnerHash.ToDisplayByteString();
byte[] md5Hmac = Hasher.ComputeMD5(ByteUtilities.ConcatBytes(md5KeyXorOpad, md5InnerHash));
byte[] md5ExpectedHmac = Hasher.ComputeMD5Hmac(keyBytes, dataBytes);
Debug.Assert(ByteUtilities.AreEqual(md5ExpectedHmac, md5Hmac));
txtHmacMd5Result.Text = md5Hmac.ToDisplayByteString();
}
catch (Exception ex)
{
MessageBox.Show("Error: " + ex.Message);
}
}
private void btnGo_Click(object sender, EventArgs e)
{
try
{
byte[] preMasterSecret = FirefoxSslDebugFileUtilities.GetPremasterSecretKey(txtPremasterSecret.Text);
string label = txtMasterSecretLabel.Text;
byte[] serverHelloRandom = txtServerRandomBytes.Text.FromWireshark();
byte[] clientHelloRandom = txtClientRandomBytes.Text.FromWireshark();
byte[] clientHelloAndServerHello = ByteUtilities.ConcatBytes(clientHelloRandom, serverHelloRandom);
byte[] masterSecret = Prf10.GenerateBytes(preMasterSecret, label, clientHelloAndServerHello, 48);
txtMasterSecret.Text = masterSecret.ToDisplayByteString();
byte[] serverHelloAndClientHello = ByteUtilities.ConcatBytes(serverHelloRandom, clientHelloRandom);
byte[] keyBlock = Prf10.GenerateBytes(masterSecret, txtKeyExpansionLabel.Text, serverHelloAndClientHello, 96);
byte[] client_write_MAC_secret = new byte[16];
byte[] server_write_MAC_secret = new byte[16];
byte[] client_write_key = new byte[16];
byte[] server_write_key = new byte[16];
byte[] client_write_IV = new byte[16];
byte[] server_write_IV = new byte[16];
Buffer.BlockCopy(keyBlock, 0, client_write_MAC_secret, 0, 16);
txtClientWriteMacKey.Text = client_write_MAC_secret.ToDisplayByteString();
Buffer.BlockCopy(keyBlock, 16, server_write_MAC_secret, 0, 16);
txtServerWriteMacKey.Text = server_write_MAC_secret.ToDisplayByteString();
Buffer.BlockCopy(keyBlock, 32, client_write_key, 0, 16);
txtClientWriteKey.Text = client_write_key.ToDisplayByteString();
Buffer.BlockCopy(keyBlock, 48, server_write_key, 0, 16);
txtServerWriteKey.Text = server_write_key.ToDisplayByteString();
Buffer.BlockCopy(keyBlock, 64, client_write_IV, 0, 16);
txtClientIV.Text = client_write_IV.ToDisplayByteString();
Buffer.BlockCopy(keyBlock, 80, server_write_IV, 0, 16);
txtServerIV.Text = server_write_IV.ToDisplayByteString();
byte[] clientHello = txtClientHello.Text.FromWireshark();
byte[] serverHello = txtServerHello.Text.FromWireshark();
byte[] certificate = txtServerHelloCertificate.Text.FromWireshark();
byte[] serverHelloDone = txtServerHelloDone.Text.FromWireshark();
byte[] clientKeyExchangeEncrypted = txtClientKeyExchange.Text.FromWireshark();
byte[] handshakeMessages = ByteUtilities.ConcatBytes(clientHello, serverHello, certificate, serverHelloDone, clientKeyExchangeEncrypted);
txtHandshakeMessages.Text = handshakeMessages.ToDisplayByteString(16);
var md5Handshake = Hasher.ComputeMD5(handshakeMessages);
txtMd5HandshakeMessages.Text = md5Handshake.ToDisplayByteString();
var sha1Handshake = Hasher.ComputeSHA1Hash(handshakeMessages);
txtSha1HandshakeMessages.Text = sha1Handshake.ToDisplayByteString();
byte[] clientVerifyData = Prf10.GenerateBytes(masterSecret, txtClientFinishedLabel.Text, ByteUtilities.ConcatBytes(md5Handshake, sha1Handshake), 12);
txtClientFinishedVerifyData.Text = clientVerifyData.ToDisplayByteString();
var clientFinishedHeaderBytes = txtClientFinishedHeader.Text.FromWireshark();
var clientFinishedHash = Hasher.ComputeTlsMD5Hmac(client_write_MAC_secret, 0x16, 0, ByteUtilities.ConcatBytes(clientFinishedHeaderBytes, clientVerifyData));
txtClientFinishedHmacMd5.Text = clientFinishedHash.ToDisplayByteString();
var clientFinishedHeaderAndVerify = ByteUtilities.ConcatBytes(clientFinishedHeaderBytes, clientVerifyData);
var clientFinishedDecrypted = ByteUtilities.ConcatBytes(clientFinishedHeaderBytes, clientVerifyData, clientFinishedHash);
Arc4 clientWriteArc4 = new Arc4(client_write_key);
var clientFinishedEncrypted = clientWriteArc4.Encrypt(clientFinishedDecrypted);
var expectedClientFinishedEncrypted = txtClientEncryptedFinishedMessage.Text.FromWireshark();
Debug.Assert(ByteUtilities.AreEqual(expectedClientFinishedEncrypted, clientFinishedEncrypted));
byte[] clientApplicationData = txtClientApplicationDataInput.Text.FromWireshark();
byte[] decryptedBytes = clientWriteArc4.Encrypt(clientApplicationData);
byte[] plainTextBytes = new byte[decryptedBytes.Length - 16];
Buffer.BlockCopy(decryptedBytes, 0, plainTextBytes, 0, plainTextBytes.Length);
string plainText = ASCIIEncoding.ASCII.GetString(plainTextBytes);
txtDecryptedClientApplicationData.Text = plainText;
byte[] hmacClientBytesReceived = new byte[16];
Buffer.BlockCopy(decryptedBytes, plainTextBytes.Length, hmacClientBytesReceived, 0, 16);
txtClientApplicationDataHmac.Text = hmacClientBytesReceived.ToDisplayByteString();
var hmacFirstClientPacket = Hasher.ComputeTlsMD5Hmac(client_write_MAC_secret, 23, 1, plainTextBytes);
Debug.Assert(ByteUtilities.AreEqual(hmacFirstClientPacket, hmacClientBytesReceived));
// get server reply
var serverHandshakeMessages = ByteUtilities.ConcatBytes(handshakeMessages, clientFinishedHeaderAndVerify);
var serverFinishedHeader = txtServerFinishedHeader.Text.FromWireshark();
md5Handshake = Hasher.ComputeMD5(serverHandshakeMessages);
sha1Handshake = Hasher.ComputeSHA1Hash(serverHandshakeMessages);
var serverVerifyData = Prf10.GenerateBytes(masterSecret, txtServerFinishedLabel.Text, ByteUtilities.ConcatBytes(md5Handshake, sha1Handshake), 12);
txtServerFinishedVerifyData.Text = serverVerifyData.ToDisplayByteString();
var serverFirstHash = Hasher.ComputeTlsMD5Hmac(server_write_MAC_secret, 0x16, 0, ByteUtilities.ConcatBytes(serverFinishedHeader, serverVerifyData));
txtServerFinishedHmacMd5.Text = serverFirstHash.ToDisplayByteString();
var serverArc4 = new Arc4(server_write_key);
var serverFinishedMessage = ByteUtilities.ConcatBytes(serverFinishedHeader, serverVerifyData, serverFirstHash);
var encryptedServerFinishedMessage = serverArc4.Encrypt(serverFinishedMessage);
Debug.Assert(ByteUtilities.AreEqual(encryptedServerFinishedMessage, txtServerEncryptedHandshakeMessage.Text.FromWireshark()));
var serverApplicationDataBytes = txtServerApplicationDataInput.Text.FromWireshark();
var decryptedServerApplicationDataBytes = serverArc4.Encrypt(serverApplicationDataBytes);
var serverPlainTextBytes = new byte[decryptedServerApplicationDataBytes.Length - 16];
Buffer.BlockCopy(decryptedServerApplicationDataBytes, 0, serverPlainTextBytes, 0, serverPlainTextBytes.Length);
var hmacServerFirstPacketReceived = new byte[16];
Buffer.BlockCopy(decryptedServerApplicationDataBytes, serverPlainTextBytes.Length, hmacServerFirstPacketReceived, 0, 16);
txtDecryptedServerApplicationData.Text = ASCIIEncoding.ASCII.GetString(serverPlainTextBytes);
var hmacServerFirstPacketComputed = Hasher.ComputeTlsMD5Hmac(server_write_MAC_secret, 23, 1, serverPlainTextBytes);
txtServerApplicationDataHmac.Text = hmacServerFirstPacketComputed.ToDisplayByteString();
Debug.Assert(ByteUtilities.AreEqual(hmacServerFirstPacketComputed, hmacServerFirstPacketComputed));
}
catch (Exception ex)
{
MessageBox.Show("Error calculating derived handshake info: " + ex.Message);
}
}