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//
// Mono.Security.Cryptography.CryptoTools
// Shared class for common cryptographic functionalities
//
// Authors:
// Sebastien Pouliot <sebastien@ximian.com>
//
// (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
// (C) 2004 Novell (http://www.novell.com)
//
using System;
using System.Security.Cryptography;
namespace Mono.Security.Cryptography {
#if INSIDE_CORLIB
internal
#else
public
#endif
sealed class KeyBuilder {
static private RandomNumberGenerator rng;
private KeyBuilder ()
{
}
static public byte[] Key (int size)
{
if (rng == null)
rng = RandomNumberGenerator.Create ();
byte[] key = new byte [size];
rng.GetBytes (key);
return key;
}
static public byte[] IV (int size)
{
if (rng == null)
rng = RandomNumberGenerator.Create ();
byte[] iv = new byte [size];
rng.GetBytes (iv);
return iv;
}
}
// Process an array as a sequence of blocks
#if INSIDE_CORLIB
internal
#else
public
#endif
class BlockProcessor {
private ICryptoTransform transform;
private byte[] block;
private int blockSize; // in bytes (not in bits)
private int blockCount;
public BlockProcessor (ICryptoTransform transform)
: this (transform, transform.InputBlockSize) {}
// some Transforms (like HashAlgorithm descendant) return 1 for
// block size (which isn't their real internal block size)
public BlockProcessor (ICryptoTransform transform, int blockSize)
{
this.transform = transform;
this.blockSize = blockSize;
block = new byte [blockSize];
}
~BlockProcessor ()
{
// zeroize our block (so we don't retain any information)
Array.Clear (block, 0, blockSize);
}
public void Initialize ()
{
Array.Clear (block, 0, blockSize);
blockCount = 0;
}
public void Core (byte[] rgb)
{
Core (rgb, 0, rgb.Length);
}
public void Core (byte[] rgb, int ib, int cb)
{
// 1. fill the rest of the "block"
int n = System.Math.Min (blockSize - blockCount, cb);
Buffer.BlockCopy (rgb, ib, block, blockCount, n);
blockCount += n;
// 2. if block is full then transform it
if (blockCount == blockSize) {
transform.TransformBlock (block, 0, blockSize, block, 0);
// 3. transform any other full block in specified buffer
int b = (int) ((cb - n) / blockSize);
for (int i=0; i < b; i++) {
transform.TransformBlock (rgb, n, blockSize, block, 0);
n += blockSize;
}
// 4. if data is still present fill the "block" with the remainder
blockCount = cb - n;
if (blockCount > 0)
Buffer.BlockCopy (rgb, n, block, 0, blockCount);
}
}
public byte[] Final ()
{
return transform.TransformFinalBlock (block, 0, blockCount);
}
}
}
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