Java BC SicBlockCipher直接输出等效于C＃

Question

我正在用C＃实现某种东西，为此我有一个单独的规范并且对我需要做的事情有很清楚的了解，但是与此同时，我有一个Java实现，并且希望在这种情况下遵循Java实现，例如尽我所能。

该代码涉及一个加密流，并且Java源代码在这里 。相关行在这里：

  private final StreamCipher enc;
...
  BlockCipher cipher;
  enc = new SICBlockCipher(cipher = new AESEngine());
  enc.init(true, new ParametersWithIV(new KeyParameter(secrets.aes), new byte[cipher.getBlockSize()]));
...
...
byte[] ptype = RLP.encodeInt((int) frame.type); //Result can be a single byte long
...
...
enc.processBytes(ptype, 0, ptype.length, buff, 0);
out.write(buff, 0, ptype.length); //encrypt and write a single byte from the SICBlockCipher stream

上面的Java BouncyCastle SicBlockCipher是a StreamCipher，允许处理少于Aes块大小的单个或少量字节。

在c＃BouncyCastle中，SicBlockCipher唯一提供的ProcessBlock和BufferedBlockCipher似乎没有提供使用ProcessBytes保证输出的方法。

我需要使用C＃BouncyCastle库来实现等效功能吗？

Answer 1

不幸的是，SicBlockCipher它本身并未实现为流密码，因此（实际上）不能直接使用此功能。

BufferedBlockCipher创建时要考虑许多不同的操作模式。它缓冲 输入
，而对于实现的计数器（CTR）模式，则SicBlockCipher需要缓冲加密的计数器块。

加密的计数器块构成密钥流，然后可以将其与明文进行XOR运算以创建密文流（或者，实际上，使用密文再次检索明文，加密是针对计数器模式的解密）。

我看到如何执行此操作的唯一方法是创建自己的实现IBlockCipher并实现所述功能。

这是计数器模式作为流密码…

using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Modes;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SicStream
{
    public class SicStreamCipher : IStreamCipher
    {
        private SicBlockCipher parent;
        private int blockSize;

        private byte[] zeroBlock;

        private byte[] blockBuffer;
        private int processed;

        public SicStreamCipher(SicBlockCipher parent)
        {
            this.parent = parent;
            this.blockSize = parent.GetBlockSize();

            this.zeroBlock = new byte[blockSize];

            this.blockBuffer = new byte[blockSize];
            // indicates that no bytes are available: lazy generation of counter blocks (they may not be needed)
            this.processed = blockSize;
        }

        public string AlgorithmName
        {
            get
            {
                return parent.AlgorithmName;
            }
        }

        public void Init(bool forEncryption, ICipherParameters parameters)
        {
            parent.Init(forEncryption, parameters);

            Array.Clear(blockBuffer, 0, blockBuffer.Length);
            processed = blockSize;
        }

        public void ProcessBytes(byte[] input, int inOff, int length, byte[] output, int outOff)
        {
            int inputProcessed = 0;
            while (inputProcessed < length)
            {
                // NOTE can be optimized further
                // the number of available bytes can be pre-calculated; too much branching
                if (processed == blockSize)
                {
                    // lazilly create a new block of key stream
                    parent.ProcessBlock(zeroBlock, 0, blockBuffer, 0);
                    processed = 0;
                }

                output[outOff + inputProcessed] = (byte)(input[inOff + inputProcessed] ^ blockBuffer[processed]);

                processed++;
                inputProcessed++;
            }
        }

        public void Reset()
        {
            parent.Reset();

            Array.Clear(blockBuffer, 0, blockBuffer.Length);
            this.processed = blockSize;
        }

        public byte ReturnByte(byte input)
        {
            if (processed == blockSize)
            {
                // lazily create a new block of key stream
                parent.ProcessBlock(zeroBlock, 0, blockBuffer, 0);
                processed = 0;
            }
            return (byte)(input ^ blockBuffer[processed++]);
        }
    }
}

…并且在此处进行了包装，以便可以在使用分组密码操作模式的代码中对其进行改装…

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Modes;

namespace SicStream
{
    /**
     * A class that implements an online Sic (segmented integer counter mode, or just counter (CTR) mode for short).
     * This class buffers one encrypted counter (representing the key stream) at a time.
     * The encryption of the counter is only performed when required, so that no key stream blocks are generated while they are not required.
     */
    public class StreamingSicBlockCipher : BufferedCipherBase
    {
        private SicStreamCipher parent;
        private int blockSize;

        public StreamingSicBlockCipher(SicBlockCipher parent)
        {
            this.parent = new SicStreamCipher(parent);
            this.blockSize = parent.GetBlockSize();
        }

        public override string AlgorithmName
        {
            get
            {
                return parent.AlgorithmName;
            }
        }

        public override byte[] DoFinal()
        {
            // returns no bytes at all, as there is no input
            return new byte[0];
        }

        public override byte[] DoFinal(byte[] input, int inOff, int length)
        {
            byte[] result = ProcessBytes(input, inOff, length);

            Reset();

            return result;
        }

        public override int GetBlockSize()
        {
            return blockSize;
        }

        public override int GetOutputSize(int inputLen)
        {
            return inputLen;
        }

        public override int GetUpdateOutputSize(int inputLen)
        {
            return inputLen;
        }

        public override void Init(bool forEncryption, ICipherParameters parameters)
        {
            parent.Init(forEncryption, parameters);
        }

        public override byte[] ProcessByte(byte input)
        {
            return new byte[] { parent.ReturnByte(input) };
        }

        public override byte[] ProcessBytes(byte[] input, int inOff, int length)
        {
            byte[] result = new byte[length];
            parent.ProcessBytes(input, inOff, length, result, 0);
            return result;
        }

        public override void Reset()
        {
            parent.Reset();
        }
    }
}

请注意，由于需要创建其他数组，因此最后一个代码效率较低。