BufferedIesCipher.cs :  » PDF » iTextSharp » Org » BouncyCastle » Crypto » C# / CSharp Open Source

using System;
using System.IO;

using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Crypto{
  public class BufferedIesCipher
    : BufferedCipherBase
  {
    private readonly IesEngine engine;
    private bool forEncryption;
    private MemoryStream buffer = new MemoryStream();

    public BufferedIesCipher(
      IesEngine engine)
    {
      if (engine == null)
        throw new ArgumentNullException("engine");

      this.engine = engine;
    }

    public override string AlgorithmName
    {
      // TODO Create IESEngine.AlgorithmName
      get { return "IES"; }
    }

    public override void Init(
      bool        forEncryption,
      ICipherParameters  parameters)
    {
      this.forEncryption = forEncryption;

      // TODO
      throw Platform.CreateNotImplementedException("IES");
    }

    public override int GetBlockSize()
    {
      return 0;
    }

    public override int GetOutputSize(
      int inputLen)
    {
      if (engine == null)
        throw new InvalidOperationException("cipher not initialised");

      int baseLen = inputLen + (int) buffer.Length;
      return forEncryption
        ?  baseLen + 20
        :  baseLen - 20;
    }

    public override int GetUpdateOutputSize(
      int inputLen)
    {
      return 0;
    }

    public override byte[] ProcessByte(
      byte input)
    {
      buffer.WriteByte(input);
      return null;
    }

    public override byte[] ProcessBytes(
      byte[]  input,
      int    inOff,
      int    length)
    {
      if (input == null)
        throw new ArgumentNullException("input");
      if (inOff < 0)
        throw new ArgumentException("inOff");
      if (length < 0)
        throw new ArgumentException("length");
      if (inOff + length > input.Length)
        throw new ArgumentException("invalid offset/length specified for input array");

      buffer.Write(input, inOff, length);
      return null;
    }

    public override byte[] DoFinal()
    {
      byte[] buf = buffer.ToArray();

      Reset();

      return engine.ProcessBlock(buf, 0, buf.Length);
    }

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

    public override void Reset()
    {
      buffer.SetLength(0);
    }
  }
}