code: public DERObject toASN1Object()
      {
          ASN1EncodableVector  v = new ASN1EncodableVector();
  
          v.add(acinfo);
          v.add(signatureAlgorithm);
          v.add(signatureValue);
  
          return new DERSequence(v);
      }
docs: Produce an object suitable for an ASN1OutputStream.
  <pre>
  AttributeCertificate ::= SEQUENCE {
  acinfo               AttributeCertificateInfo,
  signatureAlgorithm   AlgorithmIdentifier,
  signatureValue       BIT STRING
  }
  </pre>