X9IntegerConverter.cs :  » PDF » iTextSharp » Org » BouncyCastle » Asn1 » X9 » C# / CSharp Open Source

using System;

using Org.BouncyCastle.Math;
using Org.BouncyCastle.Math.EC;

namespace Org.BouncyCastle.Asn1.X9{
    public sealed class X9IntegerConverter
    {
    private X9IntegerConverter()
    {
    }

    public static int GetByteLength(
            ECFieldElement fe)
        {
      return (fe.FieldSize + 7) / 8;
        }

    public static int GetByteLength(
      ECCurve c)
    {
      return (c.FieldSize + 7) / 8;
    }

    public static byte[] IntegerToBytes(
      BigInteger  s,
      int      qLength)
    {
      byte[] bytes = s.ToByteArrayUnsigned();

      if (qLength < bytes.Length)
      {
        byte[] tmp = new byte[qLength];
        Array.Copy(bytes, bytes.Length - tmp.Length, tmp, 0, tmp.Length);
        return tmp;
      }
      else if (qLength > bytes.Length)
      {
        byte[] tmp = new byte[qLength];
        Array.Copy(bytes, 0, tmp, tmp.Length - bytes.Length, bytes.Length);
        return tmp;
      }

      return bytes;
    }
    }
}