PublicKeyEncSessionPacket.cs :  » PDF » iTextSharp » Org » BouncyCastle » Bcpg » C# / CSharp Open Source

using System;
using System.IO;

using Org.BouncyCastle.Math;

namespace Org.BouncyCastle.Bcpg{
  /// <remarks>Basic packet for a PGP public key.</remarks>
  public class PublicKeyEncSessionPacket
    : ContainedPacket //, PublicKeyAlgorithmTag
  {
    private int version;
    private long keyId;
    private PublicKeyAlgorithmTag algorithm;
    private BigInteger[] data;

    internal PublicKeyEncSessionPacket(
      BcpgInputStream bcpgIn)
    {
      version = bcpgIn.ReadByte();

      keyId |= (long)bcpgIn.ReadByte() << 56;
      keyId |= (long)bcpgIn.ReadByte() << 48;
      keyId |= (long)bcpgIn.ReadByte() << 40;
      keyId |= (long)bcpgIn.ReadByte() << 32;
      keyId |= (long)bcpgIn.ReadByte() << 24;
      keyId |= (long)bcpgIn.ReadByte() << 16;
      keyId |= (long)bcpgIn.ReadByte() << 8;
      keyId |= (uint)bcpgIn.ReadByte();

      algorithm = (PublicKeyAlgorithmTag) bcpgIn.ReadByte();

      switch ((PublicKeyAlgorithmTag) algorithm)
      {
        case PublicKeyAlgorithmTag.RsaEncrypt:
        case PublicKeyAlgorithmTag.RsaGeneral:
          data = new BigInteger[]{ new MPInteger(bcpgIn).Value };
          break;
        case PublicKeyAlgorithmTag.ElGamalEncrypt:
        case PublicKeyAlgorithmTag.ElGamalGeneral:
          data = new BigInteger[]
          {
            new MPInteger(bcpgIn).Value,
            new MPInteger(bcpgIn).Value
          };
          break;
        default:
          throw new IOException("unknown PGP public key algorithm encountered");
      }
    }

    public PublicKeyEncSessionPacket(
      long          keyId,
      PublicKeyAlgorithmTag  algorithm,
      BigInteger[]      data)
    {
      this.version = 3;
      this.keyId = keyId;
      this.algorithm = algorithm;
      this.data = (BigInteger[]) data.Clone();
    }

    public int Version
    {
      get { return version; }
    }

    public long KeyId
    {
      get { return keyId; }
    }

    public PublicKeyAlgorithmTag Algorithm
    {
      get { return algorithm; }
    }

    public BigInteger[] GetEncSessionKey()
    {
      return (BigInteger[]) data.Clone();
    }

    public override void Encode(
      BcpgOutputStream bcpgOut)
    {
      MemoryStream bOut = new MemoryStream();
      BcpgOutputStream pOut = new BcpgOutputStream(bOut);

      pOut.WriteByte((byte) version);

      pOut.WriteLong(keyId);

      pOut.WriteByte((byte)algorithm);

      for (int i = 0; i != data.Length; i++)
      {
        MPInteger.Encode(pOut, data[i]);
      }

      bcpgOut.WritePacket(PacketTag.PublicKeyEncryptedSession , bOut.ToArray(), true);
    }
  }
}