public byte[] ExpandSHA1(byte[] secret, byte[] seed, int length)
{
int hashLength = 20;
int iterations = (int)(length / hashLength);
if ((length % hashLength) > 0)
{
iterations++;
}
ByteBuffer resMacs = new ByteBuffer();
byte[] bAofi = seed;
for (int i = 1; i <= iterations; i++)
{
ByteBuffer hcseed = new ByteBuffer();
HMACSHA1 sha = new HMACSHA1(secret);
byte[] bNextAofi = sha.ComputeHash(bAofi); /// A(1) = HMAC_hash(secret, A(0)),
/// A(2) = HMAC_hash(secret, A(1)),
/// etc
HMACSHA1 sha2 = new HMACSHA1(secret);
byte[] bComputeNextHashOver = new byte[20 + seed.Length];
Array.Copy(bNextAofi, 0, bComputeNextHashOver, 0, 20);
Array.Copy(seed, 0, bComputeNextHashOver, 20, seed.Length);
byte[] bTotalHashThisIteration = sha2.ComputeHash(bComputeNextHashOver);
resMacs.AppendData(bTotalHashThisIteration); /// Append it to our total buffer
bAofi = bNextAofi; /// use next loop
}
byte[] res = resMacs.GetNSamples(length);
return res;
}
public void ComputeKeys(byte[] MasterSecret, byte[] ServerPlusClientRandomKeys)
{
// Create keyblock
ByteBuffer keyBlock = new ByteBuffer();
byte[] bKEPRF = this.PRF(MasterSecret, "key expansion", ServerPlusClientRandomKeys, this.SecurityParameters.Cipher.KeyBlockSize);
keyBlock.AppendData(bKEPRF);
this.ClientWriteMACSecret = keyBlock.GetNSamples(this.SecurityParameters.Cipher.HashSize);
this.ServerWriteMACSecret = keyBlock.GetNSamples(this.SecurityParameters.Cipher.HashSize);
this.ClientWriteKey = keyBlock.GetNSamples(this.SecurityParameters.Cipher.KeyMaterialLength);
this.ServerWriteKey = keyBlock.GetNSamples(this.SecurityParameters.Cipher.KeyMaterialLength);
if (SocketClient.ShowDebug == true)
{
System.Diagnostics.Debug.WriteLine("ClientWriteMACSecret: +++++++++++\r\n{0}\r\n++++++++++++", ByteHelper.HexStringFromByte(this.ClientWriteMACSecret, true, 16));
System.Diagnostics.Debug.WriteLine("ServerWriteMACSecret: +++++++++++\r\n{0}\r\n++++++++++++", ByteHelper.HexStringFromByte(this.ServerWriteMACSecret, true, 16));
System.Diagnostics.Debug.WriteLine("ClientWriteKey: +++++++++++\r\n{0}\r\n++++++++++++", ByteHelper.HexStringFromByte(this.ClientWriteKey, true, 16));
System.Diagnostics.Debug.WriteLine("ServerWriteKey: +++++++++++\r\n{0}\r\n++++++++++++", ByteHelper.HexStringFromByte(this.ServerWriteKey, true, 16));
}
//if (!this.IsExportable)
//{
if (this.SecurityParameters.Cipher.IVSize != 0)
{
this.ClientWriteIV = keyBlock.GetNSamples(this.SecurityParameters.Cipher.IVSize);
this.ServerWriteIV = keyBlock.GetNSamples(this.SecurityParameters.Cipher.IVSize);
}
else
{
this.ClientWriteIV = new byte[] { };
this.ServerWriteIV = new byte[] { };
}
//}
if (SocketClient.ShowDebug == true)
{
System.Diagnostics.Debug.WriteLine("ClientWriteIV: +++++++++++\r\n{0}\r\n++++++++++++", ByteHelper.HexStringFromByte(this.ClientWriteIV, true, 16));
System.Diagnostics.Debug.WriteLine("ServerWriteIV: +++++++++++\r\n{0}\r\n++++++++++++", ByteHelper.HexStringFromByte(this.ServerWriteIV, true, 16));
}
//else
//{
// // Generate final write keys
// byte[] finalClientWriteKey = PRF(this.Context.ClientWriteKey, "client write key", this.Context.RandomCS, this.ExpandedKeyMaterialSize);
// byte[] finalServerWriteKey = PRF(this.Context.ServerWriteKey, "server write key", this.Context.RandomCS, this.ExpandedKeyMaterialSize);
// this.Context.ClientWriteKey = finalClientWriteKey;
// this.Context.ServerWriteKey = finalServerWriteKey;
// if (this.IvSize > 0)
// {
// // Generate IV block
// byte[] ivBlock = PRF(CipherSuite.EmptyArray, "IV block", this.Context.RandomCS, this.IvSize * 2);
// // Generate IV keys
// this.Context.ClientWriteIV = new byte[this.IvSize];
// Buffer.BlockCopy(ivBlock, 0, this.Context.ClientWriteIV, 0, this.Context.ClientWriteIV.Length);
// this.Context.ServerWriteIV = new byte[this.IvSize];
// Buffer.BlockCopy(ivBlock, this.IvSize, this.Context.ServerWriteIV, 0, this.Context.ServerWriteIV.Length);
// }
// else
// {
// this.Context.ClientWriteIV = CipherSuite.EmptyArray;
// this.Context.ServerWriteIV = CipherSuite.EmptyArray;
// }
//}
Initialize(); /// Initialize our cryptographic grind thingies on that thingy
}
