protected SecureBuffer Expand (DisposeContext d, HMac hmac, string label, SecureBuffer seed, int length)
{
var blockSize = hmac.MacSize;
var iterations = (int)(length / blockSize);
if ((length % blockSize) > 0)
iterations++;
var resMacs = d.CreateBuffer (length);
var resOff = 0;
var tempBuf = d.CreateBuffer (blockSize);
var labelBytes = Encoding.ASCII.GetBytes (label);
for (int i = 1; i <= iterations; i++) {
hmac.Reset ();
if (i == 1) {
hmac.TransformBlock (labelBytes, 0, labelBytes.Length);
hmac.TransformBlock (seed.Buffer, 0, seed.Size);
} else {
hmac.TransformBlock (tempBuf.Buffer, 0, blockSize);
}
hmac.TransformFinalBlock (tempBuf.Buffer, 0, blockSize);
hmac.Reset ();
hmac.TransformBlock (tempBuf.Buffer, 0, blockSize);
hmac.TransformBlock (labelBytes, 0, labelBytes.Length);
hmac.TransformBlock (seed.Buffer, 0, seed.Size);
hmac.TransformFinalBlock (resMacs.Buffer, resOff, Min (length - resOff, blockSize));
resOff += blockSize;
}
return new SecureBuffer (resMacs.StealBuffer ());
}
static byte[] ComputeRecordMAC(TlsProtocolCode protocol, HMac hmac, ulong seqnum, ContentType contentType, IBufferOffsetSize fragment)
{
var header = new TlsBuffer(13);
header.Write(seqnum);
header.Write((byte)contentType);
header.Write((short)protocol);
header.Write((short)fragment.Size);
hmac.Reset();
hmac.TransformBlock(header.Buffer, 0, header.Size);
hmac.TransformBlock(fragment.Buffer, fragment.Offset, fragment.Size);
return(hmac.TransformFinalBlock());
}
static byte[] ComputeRecordMAC (TlsProtocolCode protocol, HMac hmac, ulong seqnum, ContentType contentType, IBufferOffsetSize fragment)
{
var header = new TlsBuffer (13);
header.Write (seqnum);
header.Write ((byte)contentType);
header.Write ((short)protocol);
header.Write ((short)fragment.Size);
hmac.Reset ();
hmac.TransformBlock (header.Buffer, 0, header.Size);
hmac.TransformBlock (fragment.Buffer, fragment.Offset, fragment.Size);
return hmac.TransformFinalBlock ();
}
protected SecureBuffer Expand (DisposeContext d, HMac hmac, string label, SecureBuffer seed, int length)
{
var blockSize = hmac.MacSize;
var iterations = (int)(length / blockSize);
if ((length % blockSize) > 0)
iterations++;
var resMacs = d.CreateBuffer (length);
var resOff = 0;
var tempBuf = d.CreateBuffer (blockSize);
var labelBytes = Encoding.ASCII.GetBytes (label);
for (int i = 1; i <= iterations; i++) {
hmac.Reset ();
if (i == 1) {
hmac.TransformBlock (labelBytes, 0, labelBytes.Length);
hmac.TransformBlock (seed.Buffer, 0, seed.Size);
} else {
hmac.TransformBlock (tempBuf.Buffer, 0, blockSize);
}
hmac.TransformFinalBlock (tempBuf.Buffer, 0, blockSize);
hmac.Reset ();
hmac.TransformBlock (tempBuf.Buffer, 0, blockSize);
hmac.TransformBlock (labelBytes, 0, labelBytes.Length);
hmac.TransformBlock (seed.Buffer, 0, seed.Size);
hmac.TransformFinalBlock (resMacs.Buffer, resOff, Min (length - resOff, blockSize));
resOff += blockSize;
}
return new SecureBuffer (resMacs.StealBuffer ());
}
