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Assets/BestHTTP/SecureProtocol/crypto/modes/SicBlockCipher.cs
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124
Assets/BestHTTP/SecureProtocol/crypto/modes/SicBlockCipher.cs
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#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
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using System;
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using Org.BouncyCastle.Crypto.Parameters;
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using Org.BouncyCastle.Math;
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using Org.BouncyCastle.Utilities;
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namespace Org.BouncyCastle.Crypto.Modes
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{
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/**
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* Implements the Segmented Integer Counter (SIC) mode on top of a simple
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* block cipher.
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*/
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public class SicBlockCipher
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: IBlockCipher
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{
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private readonly IBlockCipher cipher;
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private readonly int blockSize;
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private readonly byte[] counter;
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private readonly byte[] counterOut;
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private byte[] IV;
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/**
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* Basic constructor.
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*
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* @param c the block cipher to be used.
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*/
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public SicBlockCipher(IBlockCipher cipher)
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{
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this.cipher = cipher;
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this.blockSize = cipher.GetBlockSize();
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this.counter = new byte[blockSize];
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this.counterOut = new byte[blockSize];
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this.IV = new byte[blockSize];
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}
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/**
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* return the underlying block cipher that we are wrapping.
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*
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* @return the underlying block cipher that we are wrapping.
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*/
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public virtual IBlockCipher GetUnderlyingCipher()
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{
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return cipher;
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}
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public virtual void Init(
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bool forEncryption, //ignored by this CTR mode
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ICipherParameters parameters)
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{
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ParametersWithIV ivParam = parameters as ParametersWithIV;
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if (ivParam == null)
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throw new ArgumentException("CTR/SIC mode requires ParametersWithIV", "parameters");
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this.IV = Arrays.Clone(ivParam.GetIV());
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if (blockSize < IV.Length)
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throw new ArgumentException("CTR/SIC mode requires IV no greater than: " + blockSize + " bytes.");
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int maxCounterSize = System.Math.Min(8, blockSize / 2);
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if (blockSize - IV.Length > maxCounterSize)
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throw new ArgumentException("CTR/SIC mode requires IV of at least: " + (blockSize - maxCounterSize) + " bytes.");
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// if null it's an IV changed only.
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if (ivParam.Parameters != null)
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{
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cipher.Init(true, ivParam.Parameters);
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}
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Reset();
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}
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public virtual string AlgorithmName
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{
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get { return cipher.AlgorithmName + "/SIC"; }
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}
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public virtual bool IsPartialBlockOkay
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{
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get { return true; }
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}
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public virtual int GetBlockSize()
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{
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return cipher.GetBlockSize();
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}
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public virtual int ProcessBlock(
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byte[] input,
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int inOff,
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byte[] output,
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int outOff)
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{
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cipher.ProcessBlock(counter, 0, counterOut, 0);
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//
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// XOR the counterOut with the plaintext producing the cipher text
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//
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for (int i = 0; i < counterOut.Length; i++)
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{
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output[outOff + i] = (byte)(counterOut[i] ^ input[inOff + i]);
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}
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// Increment the counter
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int j = counter.Length;
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while (--j >= 0 && ++counter[j] == 0)
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{
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}
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return counter.Length;
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}
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public virtual void Reset()
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{
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Arrays.Fill(counter, (byte)0);
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Array.Copy(IV, 0, counter, 0, IV.Length);
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cipher.Reset();
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}
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}
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}
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#endif
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