private int ReadNextBlock(byte[] buffer, ref int offset, ref int count)
{
int length;
var readBytes = 0;
var blockPosition = Position % BlockSize_;
var blockStart = Position - blockPosition;
if (count <= 0 || Position >= Length)
{
return(readBytes);
}
// Read and decrypt SHA1 portion of the block
var hashPartStream = new SubStream(_baseStream, blockStart, BlockHashSize_);
if (blockPosition < BlockHashSize_)
{
var cbcHashPartStream = new CbcStream(hashPartStream, _partitionKey, new byte[0x10]);
length = (int)Math.Min(BlockHashSize_ - blockPosition, count);
cbcHashPartStream.Position = blockPosition;
readBytes += cbcHashPartStream.Read(buffer, offset, length);
Position += length;
offset += length;
count -= length;
blockPosition = Position % BlockSize_;
}
if (count <= 0 || Position >= Length)
{
return(readBytes);
}
// Read and decrypt user data
hashPartStream.Position = BlockDataIvStart_;
var dataIv = new byte[0x10];
hashPartStream.Read(dataIv, 0, 0x10);
var dataPartStream = new SubStream(_baseStream, blockStart + BlockHashSize_, BlockDataSize_);
var cbcDataPartStream = new CbcStream(dataPartStream, _partitionKey, dataIv);
length = (int)Math.Min(BlockSize_ - blockPosition, count);
cbcDataPartStream.Position = blockPosition - BlockHashSize_;
readBytes += cbcDataPartStream.Read(buffer, offset, length);
Position += length;
offset += length;
count -= length;
return(readBytes);
}
public void WriteTest3()
{
var key = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var iv = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var expected = new byte[] { 0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b, 0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e };
var ms = new MemoryStream();
var cbc = new CbcStream(ms, key, iv);
cbc.Write(new byte[16], 0, 16);
cbc.Position = 12;
Assert.ThrowsException <InvalidOperationException>(() => cbc.Write(new byte[4], 0, 4));
Assert.AreEqual(12, cbc.Position);
}
public void WriteTest1()
{
var key = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var iv = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var expected = new byte[] { 0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b, 0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e };
var ms = new MemoryStream();
var cbc = new CbcStream(ms, key, iv);
cbc.Write(new byte[16], 0, 16);
cbc.Flush();
Assert.IsTrue(ms.ToArray().SequenceEqual(expected));
Assert.AreEqual(16, cbc.Position);
Assert.AreEqual(0, ms.Position);
}
public void ReadTest1()
{
var key = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var iv = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var content = new byte[] { 0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b, 0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e };
var ms = new MemoryStream(content);
var cbc = new CbcStream(ms, key, iv);
var result = new byte[16];
var expected = new byte[16];
cbc.Read(result, 0, 16);
Assert.IsTrue(result.SequenceEqual(expected));
Assert.AreEqual(16, cbc.Position);
Assert.AreEqual(0, ms.Position);
}
public void WriteTest2()
{
var key = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var iv = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
var expected = new byte[] { 0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b, 0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e,
0xf7, 0x95, 0xbd, 0x4a, 0x52, 0xe2, 0x9e, 0xd7, 0x13, 0xd3, 0x13, 0xfa, 0x20, 0xe9, 0x8d, 0xbc };
var ms = new MemoryStream();
var cbc = new CbcStream(ms, key, iv);
cbc.Write(new byte[12], 0, 12);
cbc.Write(new byte[4], 0, 4);
cbc.Write(new byte[16], 0, 16);
cbc.Flush();
Assert.IsTrue(ms.ToArray().SequenceEqual(expected));
Assert.AreEqual(32, cbc.Position);
Assert.AreEqual(0, ms.Position);
}
private Task <bool> DoCipher(Stream input, Stream output, IProgress <ProgressReport> progress, bool decrypt)
{
var key = OnRequestKey("AES128 CBC Key", 32, out var error);
if (key == null)
{
return(Task.Factory.StartNew(() =>
{
progress.Report(new ProgressReport {
Percentage = 0, Message = error
});
return false;
}));
}
var iv = OnRequestKey("AES128 CBC IV", 32, out error);
if (iv == null)
{
return(Task.Factory.StartNew(() =>
{
progress.Report(new ProgressReport {
Percentage = 0, Message = error
});
return false;
}));
}
return(Task.Factory.StartNew(() =>
{
progress.Report(new ProgressReport {
Percentage = 0, Message = decrypt ? "Decryption..." : "Encryption..."
});
using (var cbc = new CbcStream(decrypt ? input : output, key, iv))
{
var buffer = new byte[0x10000];
var totalLength = decrypt ? cbc.Length : input.Length;
while (cbc.Position < totalLength)
{
var length = (int)Math.Min(0x10000, totalLength - cbc.Position);
if (decrypt)
{
cbc.Read(buffer, 0, length);
output.Write(buffer, 0, length);
}
else
{
input.Read(buffer, 0, length);
cbc.Write(buffer, 0, length);
}
progress.Report(new ProgressReport {
Percentage = (double)cbc.Position / totalLength * 100, Message = decrypt ? "Decryption..." : "Encryption...",
});
}
}
progress.Report(new ProgressReport {
Percentage = 100, Message = decrypt ? "Decryption finished." : "Encryption finished."
});
return true;
}));
}
