public void InvalidPaddingThrows(byte[] error, int blockSize)
{
var blkCipher = new NoOpTransform(blockSize);
var dec = new PaddingTransform(blkCipher, PaddingMode.PKCS7, true);
Assert.True(dec.CanReuseTransform);
Assert.True(dec.CanTransformMultipleBlocks);
Assert.Throws <CryptographicException>(() => dec.TransformFinalBlock(error, 0, error.Length));
}
private ICryptoTransform CreateXfrm(byte[] rgbKey, byte[] rgbIV, bool decrypt)
{
ICryptoTransform xfrm = new SM4Transform(rgbKey, decrypt);
switch (Mode)
{
case CipherMode.ECB:
break;
case CipherMode.CBC:
xfrm = new CbcTransform(xfrm, rgbIV, decrypt);
break;
default:
throw new NotSupportedException("Only CBC/ECB is supported");
}
switch (PaddingValue)
{
case PaddingMode.None:
break;
case PaddingMode.PKCS7:
#pragma warning disable 618
case PaddingTransform.Iso10126:
case PaddingTransform.AnsiX923:
#pragma warning restore 618
xfrm = new PaddingTransform(xfrm, PaddingValue, decrypt);
break;
case PaddingMode.Zeros:
xfrm = new ZerosPaddingTransform(xfrm, decrypt);
break;
default:
throw new NotSupportedException("Only PKCS#7 padding is supported");
}
return(xfrm);
}
public void TestCbc(byte[] k, byte[] iv, byte[] d)
{
var aes = Aes.Create();
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
var reference = TransformData(aes.CreateEncryptor(k, iv), d);
var ecb = Aes.Create();
ecb.Padding = PaddingMode.None;
ecb.Mode = CipherMode.ECB;
var encChain = new PaddingTransform(new CbcTransform(ecb.CreateEncryptor(k, iv), iv, false), PaddingMode.PKCS7, false);
var actual = TransformData(encChain, d);
Assert.Equal(reference, actual);
var decChain = new PaddingTransform(new CbcTransform(ecb.CreateDecryptor(k, iv), iv, true), PaddingMode.PKCS7, true);
var decrypted = TransformData(decChain, actual);
Assert.Equal(d, decrypted);
}
public void Pkcs7PaddingVector(byte[] input, int blockSize, byte[] reference)
{
var blkCipher = new NoOpSingleBlockTransform(blockSize);
var enc = new PaddingTransform(blkCipher, PaddingMode.PKCS7, false);
var dec = new PaddingTransform(blkCipher, PaddingMode.PKCS7, true);
var padded = enc.TransformFinalBlock(input, 0, input.Length);
Assert.Equal(reference.AsEnumerable(), padded);
using (var unPadded = new MemoryStream()) {
using (var cryptoStream = new CryptoStream(unPadded, dec, CryptoStreamMode.Write)) {
for (var i = 0; i < padded.Length; i += blockSize)
{
cryptoStream.Write(padded, i, blockSize);
}
}
Assert.Equal(input.AsEnumerable(), unPadded.ToArray());
}
Assert.True(enc.CanReuseTransform);
Assert.False(enc.CanTransformMultipleBlocks);
}