RSAESOAEPparams.cs :  » PDF » iTextSharp » Org » BouncyCastle » Asn1 » Pkcs » C# / CSharp Open Source

using System;

using Org.BouncyCastle.Asn1.Oiw;
using Org.BouncyCastle.Asn1.X509;

namespace Org.BouncyCastle.Asn1.Pkcs{
  public class RsaesOaepParameters
    : Asn1Encodable
  {
    private AlgorithmIdentifier hashAlgorithm;
    private AlgorithmIdentifier maskGenAlgorithm;
    private AlgorithmIdentifier pSourceAlgorithm;

    public readonly static AlgorithmIdentifier DefaultHashAlgorithm = new AlgorithmIdentifier(OiwObjectIdentifiers.IdSha1, DerNull.Instance);
    public readonly static AlgorithmIdentifier DefaultMaskGenFunction = new AlgorithmIdentifier(PkcsObjectIdentifiers.IdMgf1, DefaultHashAlgorithm);
    public readonly static AlgorithmIdentifier DefaultPSourceAlgorithm = new AlgorithmIdentifier(PkcsObjectIdentifiers.IdPSpecified, new DerOctetString(new byte[0]));

    public static RsaesOaepParameters GetInstance(
      object obj)
    {
      if (obj is RsaesOaepParameters)
      {
        return (RsaesOaepParameters)obj;
      }
      else if (obj is Asn1Sequence)
      {
        return new RsaesOaepParameters((Asn1Sequence)obj);
      }

      throw new ArgumentException("Unknown object in factory: " + obj.GetType().FullName, "obj");
    }

    /**
     * The default version
     */
    public RsaesOaepParameters()
    {
      hashAlgorithm = DefaultHashAlgorithm;
      maskGenAlgorithm = DefaultMaskGenFunction;
      pSourceAlgorithm = DefaultPSourceAlgorithm;
    }

    public RsaesOaepParameters(
      AlgorithmIdentifier hashAlgorithm,
      AlgorithmIdentifier maskGenAlgorithm,
      AlgorithmIdentifier pSourceAlgorithm)
    {
      this.hashAlgorithm = hashAlgorithm;
      this.maskGenAlgorithm = maskGenAlgorithm;
      this.pSourceAlgorithm = pSourceAlgorithm;
    }

    public RsaesOaepParameters(
      Asn1Sequence seq)
    {
      hashAlgorithm = DefaultHashAlgorithm;
      maskGenAlgorithm = DefaultMaskGenFunction;
      pSourceAlgorithm = DefaultPSourceAlgorithm;

      for (int i = 0; i != seq.Count; i++)
      {
        Asn1TaggedObject o = (Asn1TaggedObject)seq[i];

        switch (o.TagNo)
        {
          case 0:
            hashAlgorithm = AlgorithmIdentifier.GetInstance(o, true);
            break;
          case 1:
            maskGenAlgorithm = AlgorithmIdentifier.GetInstance(o, true);
            break;
          case 2:
            pSourceAlgorithm = AlgorithmIdentifier.GetInstance(o, true);
            break;
          default:
            throw new ArgumentException("unknown tag");
        }
      }
    }

    public AlgorithmIdentifier HashAlgorithm
    {
      get { return hashAlgorithm; }
    }

    public AlgorithmIdentifier MaskGenAlgorithm
    {
      get { return maskGenAlgorithm; }
    }

    public AlgorithmIdentifier PSourceAlgorithm
    {
      get { return pSourceAlgorithm; }
    }

    /**
     * <pre>
     *  RSAES-OAEP-params ::= SEQUENCE {
     *     hashAlgorithm      [0] OAEP-PSSDigestAlgorithms     DEFAULT sha1,
     *     maskGenAlgorithm   [1] PKCS1MGFAlgorithms  DEFAULT mgf1SHA1,
     *     pSourceAlgorithm   [2] PKCS1PSourceAlgorithms  DEFAULT pSpecifiedEmpty
     *   }
     *
     *   OAEP-PSSDigestAlgorithms    ALGORITHM-IDENTIFIER ::= {
     *     { OID id-sha1 PARAMETERS NULL   }|
     *     { OID id-sha256 PARAMETERS NULL }|
     *     { OID id-sha384 PARAMETERS NULL }|
     *     { OID id-sha512 PARAMETERS NULL },
     *     ...  -- Allows for future expansion --
     *   }
     *   PKCS1MGFAlgorithms    ALGORITHM-IDENTIFIER ::= {
     *     { OID id-mgf1 PARAMETERS OAEP-PSSDigestAlgorithms },
     *    ...  -- Allows for future expansion --
     *   }
     *   PKCS1PSourceAlgorithms    ALGORITHM-IDENTIFIER ::= {
     *     { OID id-pSpecified PARAMETERS OCTET STRING },
     *     ...  -- Allows for future expansion --
     *  }
     * </pre>
     * @return the asn1 primitive representing the parameters.
     */
    public override Asn1Object ToAsn1Object()
    {
      Asn1EncodableVector v = new Asn1EncodableVector();

      if (!hashAlgorithm.Equals(DefaultHashAlgorithm))
      {
        v.Add(new DerTaggedObject(true, 0, hashAlgorithm));
      }

      if (!maskGenAlgorithm.Equals(DefaultMaskGenFunction))
      {
        v.Add(new DerTaggedObject(true, 1, maskGenAlgorithm));
      }

      if (!pSourceAlgorithm.Equals(DefaultPSourceAlgorithm))
      {
        v.Add(new DerTaggedObject(true, 2, pSourceAlgorithm));
      }

      return new DerSequence(v);
    }
  }
}