97 lines
3.3 KiB
C#
97 lines
3.3 KiB
C#
using System;
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using Org.BouncyCastle.Crypto.Parameters;
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namespace Org.BouncyCastle.Crypto.Engines
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{
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/// <remarks>A class that provides a basic DESede (or Triple DES) engine.</remarks>
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public class DesEdeEngine
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: DesEngine
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{
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private int[] workingKey1, workingKey2, workingKey3;
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private bool forEncryption;
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/**
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* initialise a DESede cipher.
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*
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* @param forEncryption whether or not we are for encryption.
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* @param parameters the parameters required to set up the cipher.
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* @exception ArgumentException if the parameters argument is
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* inappropriate.
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*/
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public override void Init(
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bool forEncryption,
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ICipherParameters parameters)
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{
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if (!(parameters is KeyParameter))
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{
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throw new ArgumentException("invalid parameter passed to DESede init - " + parameters.GetType().ToString());
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}
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byte[] keyMaster = ((KeyParameter)parameters).GetKey();
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byte[] key1 = new byte[8], key2 = new byte[8], key3 = new byte[8];
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this.forEncryption = forEncryption;
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if (keyMaster.Length == 24)
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{
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Array.Copy(keyMaster, 0, key1, 0, key1.Length);
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Array.Copy(keyMaster, 8, key2, 0, key2.Length);
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Array.Copy(keyMaster, 16, key3, 0, key3.Length);
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workingKey1 = GenerateWorkingKey(forEncryption, key1);
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workingKey2 = GenerateWorkingKey(!forEncryption, key2);
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workingKey3 = GenerateWorkingKey(forEncryption, key3);
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}
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else // 16 byte key
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{
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Array.Copy(keyMaster, 0, key1, 0, key1.Length);
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Array.Copy(keyMaster, 8, key2, 0, key2.Length);
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workingKey1 = GenerateWorkingKey(forEncryption, key1);
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workingKey2 = GenerateWorkingKey(!forEncryption, key2);
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workingKey3 = workingKey1;
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}
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}
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public override string AlgorithmName
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{
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get { return "DESede"; }
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}
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public override int GetBlockSize()
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{
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return BLOCK_SIZE;
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}
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public override 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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if (workingKey1 == null)
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throw new InvalidOperationException("DESede engine not initialised");
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if ((inOff + BLOCK_SIZE) > input.Length)
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throw new DataLengthException("input buffer too short");
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if ((outOff + BLOCK_SIZE) > output.Length)
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throw new DataLengthException("output buffer too short");
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if (forEncryption)
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{
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DesFunc(workingKey1, input, inOff, output, outOff);
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DesFunc(workingKey2, output, outOff, output, outOff);
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DesFunc(workingKey3, output, outOff, output, outOff);
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}
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else
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{
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DesFunc(workingKey3, input, inOff, output, outOff);
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DesFunc(workingKey2, output, outOff, output, outOff);
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DesFunc(workingKey1, output, outOff, output, outOff);
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}
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return BLOCK_SIZE;
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}
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public override void Reset()
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{
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}
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}
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}
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