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

using System;

using Org.BouncyCastle.Crypto.Parameters;

namespace Org.BouncyCastle.Crypto{
  public class BufferedStreamCipher
    : BufferedCipherBase
  {
    private readonly IStreamCipher cipher;

    public BufferedStreamCipher(
      IStreamCipher cipher)
    {
      if (cipher == null)
        throw new ArgumentNullException("cipher");

      this.cipher = cipher;
    }

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

    public override void Init(
      bool        forEncryption,
      ICipherParameters  parameters)
    {
      if (parameters is ParametersWithRandom)
      {
        parameters = ((ParametersWithRandom) parameters).Parameters;
      }

      cipher.Init(forEncryption, parameters);
    }

    public override int GetBlockSize()
    {
      return 0;
    }

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

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

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

    public override int ProcessByte(
      byte  input,
      byte[]  output,
      int    outOff)
    {
      if (outOff >= output.Length)
        throw new DataLengthException("output buffer too short");

      output[outOff] = cipher.ReturnByte(input);
      return 1;
    }

    public override byte[] ProcessBytes(
      byte[]  input,
      int    inOff,
      int    length)
    {
      if (length < 1)
        return null;

      byte[] output = new byte[length];
      cipher.ProcessBytes(input, inOff, length, output, 0);
      return output;
    }

    public override int ProcessBytes(
      byte[]  input,
      int    inOff,
      int    length,
      byte[]  output,
      int    outOff)
    {
      if (length < 1)
        return 0;

      if (length > 0)
      {
        cipher.ProcessBytes(input, inOff, length, output, outOff);
      }

      return length;
    }

    public override byte[] DoFinal()
    {
      Reset();

      return EmptyBuffer;
    }

    public override byte[] DoFinal(
      byte[]  input,
      int    inOff,
      int    length)
    {
      if (length < 1)
        return EmptyBuffer;

      byte[] output = ProcessBytes(input, inOff, length);

      Reset();

      return output;
    }

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