MessageImprint.cs :  » PDF » iTextSharp » Org » BouncyCastle » Asn1 » Tsp » C# / CSharp Open Source

using System;

using Org.BouncyCastle.Asn1.X509;

namespace Org.BouncyCastle.Asn1.Tsp{
  public class MessageImprint
    : Asn1Encodable
  {
    private readonly AlgorithmIdentifier  hashAlgorithm;
    private readonly byte[]          hashedMessage;

    /**
     * @param o
     * @return a MessageImprint object.
     */
    public static MessageImprint GetInstance(
      object o)
    {
      if (o == null || o is MessageImprint)
      {
        return (MessageImprint) o;
      }

      if (o is Asn1Sequence)
      {
        return new MessageImprint((Asn1Sequence) o);
      }

      throw new ArgumentException(
        "Unknown object in 'MessageImprint' factory: " + o.GetType().FullName);
    }

    private MessageImprint(
      Asn1Sequence seq)
    {
      if (seq.Count != 2)
        throw new ArgumentException("Wrong number of elements in sequence", "seq");

      this.hashAlgorithm = AlgorithmIdentifier.GetInstance(seq[0]);
      this.hashedMessage = Asn1OctetString.GetInstance(seq[1]).GetOctets();
    }

    public MessageImprint(
      AlgorithmIdentifier  hashAlgorithm,
      byte[]        hashedMessage)
    {
      this.hashAlgorithm = hashAlgorithm;
      this.hashedMessage = hashedMessage;
    }

    public AlgorithmIdentifier HashAlgorithm
    {
      get { return hashAlgorithm; }
    }

    public byte[] GetHashedMessage()
    {
      return hashedMessage;
    }

    /**
     * <pre>
     *    MessageImprint ::= SEQUENCE  {
     *       hashAlgorithm                AlgorithmIdentifier,
     *       hashedMessage                OCTET STRING  }
     * </pre>
     */
    public override Asn1Object ToAsn1Object()
    {
      return new DerSequence(hashAlgorithm, new DerOctetString(hashedMessage));
    }
  }
}