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

using System;

using Org.BouncyCastle.Math;

namespace Org.BouncyCastle.Bcpg{
  /// <remarks>Base class for an RSA secret (or priate) key.</remarks>
  public class RsaSecretBcpgKey
    : BcpgObject, IBcpgKey
  {
    private readonly MPInteger d, p, q, u;
    private readonly BigInteger expP, expQ, crt;

    public RsaSecretBcpgKey(
      BcpgInputStream bcpgIn)
    {
      this.d = new MPInteger(bcpgIn);
      this.p = new MPInteger(bcpgIn);
      this.q = new MPInteger(bcpgIn);
      this.u = new MPInteger(bcpgIn);

      this.expP = d.Value.Remainder(p.Value.Subtract(BigInteger.One));
      this.expQ = d.Value.Remainder(q.Value.Subtract(BigInteger.One));
      this.crt = q.Value.ModInverse(p.Value);
    }

    public RsaSecretBcpgKey(
      BigInteger d,
      BigInteger p,
      BigInteger q)
    {
      // PGP requires (p < q)
      int cmp = p.CompareTo(q);
      if (cmp >= 0)
      {
        if (cmp == 0)
          throw new ArgumentException("p and q cannot be equal");

        BigInteger tmp = p;
        p = q;
        q = tmp;
      }

      this.d = new MPInteger(d);
      this.p = new MPInteger(p);
      this.q = new MPInteger(q);
      this.u = new MPInteger(p.ModInverse(q));

      this.expP = d.Remainder(p.Subtract(BigInteger.One));
      this.expQ = d.Remainder(q.Subtract(BigInteger.One));
      this.crt = q.ModInverse(p);
    }

    public BigInteger Modulus
    {
      get { return p.Value.Multiply(q.Value); }
    }

    public BigInteger PrivateExponent
    {
      get { return d.Value; }
    }

    public BigInteger PrimeP
    {
      get { return p.Value; }
    }

    public BigInteger PrimeQ
    {
      get { return q.Value; }
    }

    public BigInteger PrimeExponentP
    {
      get { return expP; }
    }

    public BigInteger PrimeExponentQ
    {
      get { return expQ; }
    }

    public BigInteger CrtCoefficient
    {
      get { return crt; }
    }

    /// <summary>The format, as a string, always "PGP".</summary>
    public string Format
    {
      get { return "PGP"; }
    }

    /// <summary>Return the standard PGP encoding of the key.</summary>
    public override byte[] GetEncoded()
    {
      try
      {
        return base.GetEncoded();
      }
      catch (Exception)
      {
        return null;
      }
    }

    public override void Encode(
      BcpgOutputStream bcpgOut)
    {
      bcpgOut.WriteObjects(d, p, q, u);
    }
  }
}