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

using System;
using System.IO;
using System.Text;

using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Macs;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.IO;

namespace Org.BouncyCastle.Crypto.Tls{
  /// <remarks>Some helper fuctions for MicroTLS.</remarks>
  public class TlsUtilities
  {
    internal static void WriteUint8(short i, Stream os)
    {
      os.WriteByte((byte)i);
    }

    internal static void WriteUint8(short i, byte[] buf, int offset)
    {
      buf[offset] = (byte)i;
    }

    internal static void WriteUint16(int i, Stream os)
    {
      os.WriteByte((byte)(i >> 8));
      os.WriteByte((byte)i);
    }

    internal static void WriteUint16(int i, byte[] buf, int offset)
    {
      buf[offset] = (byte)(i >> 8);
      buf[offset + 1] = (byte)i;
    }

    internal static void WriteUint24(int i, Stream os)
    {
      os.WriteByte((byte)(i >> 16));
      os.WriteByte((byte)(i >> 8));
      os.WriteByte((byte)i);
    }

    internal static void WriteUint24(int i, byte[] buf, int offset)
    {
      buf[offset] = (byte)(i >> 16);
      buf[offset + 1] = (byte)(i >> 8);
      buf[offset + 2] = (byte)(i);
    }

    internal static void WriteUint64(long i, Stream os)
    {
      os.WriteByte((byte)(i >> 56));
      os.WriteByte((byte)(i >> 48));
      os.WriteByte((byte)(i >> 40));
      os.WriteByte((byte)(i >> 32));
      os.WriteByte((byte)(i >> 24));
      os.WriteByte((byte)(i >> 16));
      os.WriteByte((byte)(i >> 8));
      os.WriteByte((byte)i);
    }

    internal static void WriteUint64(long i, byte[] buf, int offset)
    {
      buf[offset] = (byte)(i >> 56);
      buf[offset + 1] = (byte)(i >> 48);
      buf[offset + 2] = (byte)(i >> 40);
      buf[offset + 3] = (byte)(i >> 32);
      buf[offset + 4] = (byte)(i >> 24);
      buf[offset + 5] = (byte)(i >> 16);
      buf[offset + 6] = (byte)(i >> 8);
      buf[offset + 7] = (byte)(i);
    }

    internal static void WriteOpaque8(byte[] buf, Stream os)
    {
      WriteUint8((short)buf.Length, os);
      os.Write(buf, 0, buf.Length);
    }

    internal static void WriteOpaque16(byte[] buf, Stream os)
    {
      WriteUint16(buf.Length, os);
      os.Write(buf, 0, buf.Length);
    }

    internal static void WriteOpaque24(byte[] buf, Stream os)
    {
      WriteUint24(buf.Length, os);
      os.Write(buf, 0, buf.Length);
    }

    internal static short ReadUint8(Stream inStr)
    {
      int i = inStr.ReadByte();
      if (i < 0)
      {
        throw new EndOfStreamException();
      }
      return (short)i;
    }

    internal static int ReadUint16(Stream inStr)
    {
      int i1 = inStr.ReadByte();
      int i2 = inStr.ReadByte();
      if ((i1 | i2) < 0)
      {
        throw new EndOfStreamException();
      }
      return i1 << 8 | i2;
    }

    internal static int ReadUint24(Stream inStr)
    {
      int i1 = inStr.ReadByte();
      int i2 = inStr.ReadByte();
      int i3 = inStr.ReadByte();
      if ((i1 | i2 | i3) < 0)
      {
        throw new EndOfStreamException();
      }
      return (i1 << 16) | (i2 << 8) | i3;
    }

    internal static void ReadFully(byte[] buf, Stream inStr)
    {
      if (Streams.ReadFully(inStr, buf, 0, buf.Length) < buf.Length)
        throw new EndOfStreamException();
    }

    internal static byte[] ReadOpaque8(Stream inStr)
    {
      short length = ReadUint8(inStr);
      byte[] bytes = new byte[length];
      ReadFully(bytes, inStr);
      return bytes;
    }

    internal static byte[] ReadOpaque16(Stream inStr)
    {
      int length = ReadUint16(inStr);
      byte[] bytes = new byte[length];
      ReadFully(bytes, inStr);
      return bytes;
    }

    internal static void CheckVersion(byte[] readVersion, TlsProtocolHandler handler)
    {
      if ((readVersion[0] != 3) || (readVersion[1] != 1))
      {
        handler.FailWithError(TlsProtocolHandler.AL_fatal, TlsProtocolHandler.AP_protocol_version);
      }
    }

    internal static void CheckVersion(Stream inStr, TlsProtocolHandler handler)
    {
      int i1 = inStr.ReadByte();
      int i2 = inStr.ReadByte();
      if ((i1 != 3) || (i2 != 1))
      {
        handler.FailWithError(TlsProtocolHandler.AL_fatal, TlsProtocolHandler.AP_protocol_version);
      }
    }

    internal static void WriteVersion(Stream os)
    {
      os.WriteByte(3);
      os.WriteByte(1);
    }

    internal static void WriteVersion(byte[] buf, int offset)
    {
      buf[offset] = 3;
      buf[offset + 1] = 1;
    }

    private static void hmac_hash(IDigest digest, byte[] secret, byte[] seed, byte[] output)
    {
      HMac mac = new HMac(digest);
      KeyParameter param = new KeyParameter(secret);
      byte[] a = seed;
      int size = digest.GetDigestSize();
      int iterations = (output.Length + size - 1) / size;
      byte[] buf = new byte[mac.GetMacSize()];
      byte[] buf2 = new byte[mac.GetMacSize()];
      for (int i = 0; i < iterations; i++)
      {
        mac.Init(param);
        mac.BlockUpdate(a, 0, a.Length);
        mac.DoFinal(buf, 0);
        a = buf;
        mac.Init(param);
        mac.BlockUpdate(a, 0, a.Length);
        mac.BlockUpdate(seed, 0, seed.Length);
        mac.DoFinal(buf2, 0);
        Array.Copy(buf2, 0, output, (size * i), System.Math.Min(size, output.Length - (size * i)));
      }
    }

    internal static void PRF(
      byte[]  secret,
      String  asciiLabel,
      byte[]  seed,
      byte[]  buf)
    {
      byte[] label = Encoding.ASCII.GetBytes(asciiLabel);

      int s_half = (secret.Length + 1) / 2;
      byte[] s1 = new byte[s_half];
      byte[] s2 = new byte[s_half];
      Array.Copy(secret, 0, s1, 0, s_half);
      Array.Copy(secret, secret.Length - s_half, s2, 0, s_half);

      byte[] ls = new byte[label.Length + seed.Length];
      Array.Copy(label, 0, ls, 0, label.Length);
      Array.Copy(seed, 0, ls, label.Length, seed.Length);

      byte[] prf = new byte[buf.Length];
      hmac_hash(new MD5Digest(), s1, ls, prf);
      hmac_hash(new Sha1Digest(), s2, ls, buf);
      for (int i = 0; i < buf.Length; i++)
      {
        buf[i] ^= prf[i];
      }
    }
  }
}