public override void InitializeCipher()
{
// Create the HMAC algorithm
if (IsClient)
{
ClientHMac = HMac.Create(Cipher.HashAlgorithmType, ClientWriteMac);
ServerHMac = HMac.Create(Cipher.HashAlgorithmType, ServerWriteMac);
}
else
{
ServerHMac = HMac.Create(Cipher.HashAlgorithmType, ServerWriteMac);
ClientHMac = HMac.Create(Cipher.HashAlgorithmType, ClientWriteMac);
}
}
protected override SecureBuffer PRF(DisposeContext d, SecureBuffer secret, string label, SecureBuffer data, int length)
{
/* Secret Length calc exmplain from the RFC2246. Section 5
*
* S1 and S2 are the two halves of the secret and each is the same
* length. S1 is taken from the first half of the secret, S2 from the
* second half. Their length is created by rounding up the length of the
* overall secret divided by two; thus, if the original secret is an odd
* number of bytes long, the last byte of S1 will be the same as the
* first byte of S2.
*/
// split secret in 2
int secretLen = secret.Size >> 1;
// rounding up
if ((secret.Size & 0x1) == 0x1)
{
secretLen++;
}
// Secret 1
var secret1 = d.CreateBuffer(secretLen);
Buffer.BlockCopy(secret.Buffer, 0, secret1.Buffer, 0, secretLen);
// Secret2
var secret2 = d.CreateBuffer(secretLen);
Buffer.BlockCopy(secret.Buffer, (secret.Size - secretLen), secret2.Buffer, 0, secretLen);
// Secret 1 processing
var p_md5 = d.Add(Expand(d, HMac.Create(HashAlgorithmType.Md5, secret1), label, data, length));
// Secret 2 processing
var p_sha = d.Add(Expand(d, HMac.Create(HashAlgorithmType.Sha1, secret2), label, data, length));
// Perfor XOR of both results
var masterSecret = new SecureBuffer(length);
for (int i = 0; i < length; i++)
{
masterSecret.Buffer[i] = (byte)(p_md5.Buffer[i] ^ p_sha.Buffer[i]);
}
return(masterSecret);
}
protected override SecureBuffer PRF(DisposeContext d, SecureBuffer secret, string label, SecureBuffer data, int length)
{
return(Expand(d, HMac.Create(HandshakeHashType, secret), label, data, length));
}