Rfc3211WrapEngine
using Org.BouncyCastle.Crypto.Modes;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
using System;
namespace Org.BouncyCastle.Crypto.Engines
{
public class Rfc3211WrapEngine : IWrapper
{
private CbcBlockCipher engine;
private ParametersWithIV param;
private bool forWrapping;
private SecureRandom rand;
public virtual string AlgorithmName => engine.UnderlyingCipher.AlgorithmName + "/RFC3211Wrap";
public Rfc3211WrapEngine(IBlockCipher engine)
{
this.engine = new CbcBlockCipher(engine);
}
public virtual void Init(bool forWrapping, ICipherParameters param)
{
this.forWrapping = forWrapping;
ParametersWithRandom parametersWithRandom = param as ParametersWithRandom;
if (parametersWithRandom != null) {
this.param = (parametersWithRandom.Parameters as ParametersWithIV);
rand = parametersWithRandom.Random;
} else {
this.param = (param as ParametersWithIV);
rand = (forWrapping ? CryptoServicesRegistrar.GetSecureRandom() : null);
}
if (this.param == null)
throw new ArgumentException("RFC3211Wrap requires an IV", "param");
}
public virtual byte[] Wrap(byte[] inBytes, int inOff, int inLen)
{
if (!forWrapping)
throw new InvalidOperationException("not set for wrapping");
if (inLen > 255 || inLen < 0)
throw new ArgumentException("input must be from 0 to 255 bytes", "inLen");
engine.Init(true, param);
int blockSize = engine.GetBlockSize();
byte[] array = (inLen + 4 >= blockSize * 2) ? new byte[((inLen + 4) % blockSize == 0) ? (inLen + 4) : (((inLen + 4) / blockSize + 1) * blockSize)] : new byte[blockSize * 2];
array[0] = (byte)inLen;
Array.Copy(inBytes, inOff, array, 4, inLen);
rand.NextBytes(array, inLen + 4, array.Length - inLen - 4);
array[1] = (byte)(~array[4]);
array[2] = (byte)(~array[5]);
array[3] = (byte)(~array[6]);
for (int i = 0; i < array.Length; i += blockSize) {
engine.ProcessBlock(array, i, array, i);
}
for (int j = 0; j < array.Length; j += blockSize) {
engine.ProcessBlock(array, j, array, j);
}
return array;
}
public virtual byte[] Unwrap(byte[] inBytes, int inOff, int inLen)
{
if (forWrapping)
throw new InvalidOperationException("not set for unwrapping");
int blockSize = engine.GetBlockSize();
if (inLen < 2 * blockSize)
throw new InvalidCipherTextException("input too short");
byte[] array = new byte[inLen];
byte[] array2 = new byte[blockSize];
Array.Copy(inBytes, inOff, array, 0, inLen);
Array.Copy(inBytes, inOff, array2, 0, array2.Length);
engine.Init(false, new ParametersWithIV(param.Parameters, array2));
for (int i = blockSize; i < array.Length; i += blockSize) {
engine.ProcessBlock(array, i, array, i);
}
Array.Copy(array, array.Length - array2.Length, array2, 0, array2.Length);
engine.Init(false, new ParametersWithIV(param.Parameters, array2));
engine.ProcessBlock(array, 0, array, 0);
engine.Init(false, param);
for (int j = 0; j < array.Length; j += blockSize) {
engine.ProcessBlock(array, j, array, j);
}
bool flag = array[0] > array.Length - 4;
byte[] array3 = (!flag) ? new byte[array[0]] : new byte[array.Length - 4];
Array.Copy(array, 4, array3, 0, array3.Length);
int num = 0;
for (int k = 0; k != 3; k++) {
byte b = (byte)(~array[1 + k]);
num |= (b ^ array[4 + k]);
}
Array.Clear(array, 0, array.Length);
if ((num != 0) | flag)
throw new InvalidCipherTextException("wrapped key corrupted");
return array3;
}
}
}