RSASSAPSSparams.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 RsassaPssParameters
    : Asn1Encodable
  {
    private AlgorithmIdentifier hashAlgorithm;
    private AlgorithmIdentifier maskGenAlgorithm;
    private DerInteger saltLength;
    private DerInteger trailerField;

    public readonly static AlgorithmIdentifier DefaultHashAlgorithm = new AlgorithmIdentifier(OiwObjectIdentifiers.IdSha1, DerNull.Instance);
    public readonly static AlgorithmIdentifier DefaultMaskGenFunction = new AlgorithmIdentifier(PkcsObjectIdentifiers.IdMgf1, DefaultHashAlgorithm);
    public readonly static DerInteger DefaultSaltLength = new DerInteger(20);
    public readonly static DerInteger DefaultTrailerField = new DerInteger(1);

    public static RsassaPssParameters GetInstance(
      object obj)
    {
      if (obj == null || obj is RsassaPssParameters)
      {
        return (RsassaPssParameters)obj;
      }

      if (obj is Asn1Sequence)
      {
        return new RsassaPssParameters((Asn1Sequence)obj);
      }

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

    /**
     * The default version
     */
    public RsassaPssParameters()
    {
      hashAlgorithm = DefaultHashAlgorithm;
      maskGenAlgorithm = DefaultMaskGenFunction;
      saltLength = DefaultSaltLength;
      trailerField = DefaultTrailerField;
    }

    public RsassaPssParameters(
      AlgorithmIdentifier hashAlgorithm,
      AlgorithmIdentifier maskGenAlgorithm,
      DerInteger saltLength,
      DerInteger trailerField)
    {
      this.hashAlgorithm = hashAlgorithm;
      this.maskGenAlgorithm = maskGenAlgorithm;
      this.saltLength = saltLength;
      this.trailerField = trailerField;
    }

    public RsassaPssParameters(
      Asn1Sequence seq)
    {
      hashAlgorithm = DefaultHashAlgorithm;
      maskGenAlgorithm = DefaultMaskGenFunction;
      saltLength = DefaultSaltLength;
      trailerField = DefaultTrailerField;

      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:
            saltLength = DerInteger.GetInstance(o, true);
            break;
          case 3:
            trailerField = DerInteger.GetInstance(o, true);
            break;
          default:
            throw new ArgumentException("unknown tag");
        }
      }
    }

    public AlgorithmIdentifier HashAlgorithm
    {
      get { return hashAlgorithm; }
    }

    public AlgorithmIdentifier MaskGenAlgorithm
    {
      get { return maskGenAlgorithm; }
    }

    public DerInteger SaltLength
    {
      get { return saltLength; }
    }

    public DerInteger TrailerField
    {
      get { return trailerField; }
    }

    /**
     * <pre>
     * RSASSA-PSS-params ::= SEQUENCE {
     *   hashAlgorithm      [0] OAEP-PSSDigestAlgorithms  DEFAULT sha1,
     *    maskGenAlgorithm   [1] PKCS1MGFAlgorithms  DEFAULT mgf1SHA1,
     *    saltLength         [2] INTEGER  DEFAULT 20,
     *    trailerField       [3] TrailerField  DEFAULT trailerFieldBC
     *  }
     *
     * 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 --
     * }
     *
     * TrailerField ::= INTEGER { trailerFieldBC(1) }
     * </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 (!saltLength.Equals(DefaultSaltLength))
      {
        v.Add(new DerTaggedObject(true, 2, saltLength));
      }

      if (!trailerField.Equals(DefaultTrailerField))
      {
        v.Add(new DerTaggedObject(true, 3, trailerField));
      }

      return new DerSequence(v);
    }
  }
}