iTextSharp.text.pdf.security.DigestAlgorithms.GetAllowedDigests C# (CSharp) Method

        public static String GetAllowedDigests(String name)
        {
            string ret;
            allowedDigests.TryGetValue(name.ToUpperInvariant(), out ret);
            return ret;
        }

        /**
         * Get RFC 3161 timeStampToken.
         * Method may return null indicating that timestamp should be skipped.
         * @param imprint data imprint to be time-stamped
         * @return encoded, TSA signed data of the timeStampToken
         */
        public virtual byte[] GetTimeStampToken(byte[] imprint)
        {
            byte[] respBytes = null;
            // Setup the time stamp request
            TimeStampRequestGenerator tsqGenerator = new TimeStampRequestGenerator();

            tsqGenerator.SetCertReq(true);
            if (!string.IsNullOrEmpty(tsaReqPolicy))
            {
                tsqGenerator.SetReqPolicy(tsaReqPolicy);
            }
            // tsqGenerator.setReqPolicy("1.3.6.1.4.1.601.10.3.1");
            BigInteger       nonce   = BigInteger.ValueOf(DateTime.Now.Ticks + Environment.TickCount);
            TimeStampRequest request = tsqGenerator.Generate(DigestAlgorithms.GetAllowedDigests(digestAlgorithm), imprint, nonce);

            byte[] requestBytes = request.GetEncoded();

            // Call the communications layer
            respBytes = GetTSAResponse(requestBytes);

            // Handle the TSA response
            TimeStampResponse response = new TimeStampResponse(respBytes);

            // validate communication level attributes (RFC 3161 PKIStatus)
            response.Validate(request);
            PkiFailureInfo failure = response.GetFailInfo();
            int            value   = (failure == null) ? 0 : failure.IntValue;

            if (value != 0)
            {
                // @todo: Translate value of 15 error codes defined by PKIFailureInfo to string
                throw new IOException(MessageLocalization.GetComposedMessage("invalid.tsa.1.response.code.2", tsaURL, value));
            }
            // @todo: validate the time stap certificate chain (if we want
            //        assure we do not sign using an invalid timestamp).

            // extract just the time stamp token (removes communication status info)
            TimeStampToken tsToken = response.TimeStampToken;

            if (tsToken == null)
            {
                throw new IOException(MessageLocalization.GetComposedMessage("tsa.1.failed.to.return.time.stamp.token.2", tsaURL, response.GetStatusString()));
            }
            TimeStampTokenInfo tsTokenInfo = tsToken.TimeStampInfo; // to view details

            byte[] encoded = tsToken.GetEncoded();

            LOGGER.Info("Timestamp generated: " + tsTokenInfo.GenTime);
            if (tsaInfo != null)
            {
                tsaInfo.InspectTimeStampTokenInfo(tsTokenInfo);
            }
            // Update our token size estimate for the next call (padded to be safe)
            this.tokenSizeEstimate = encoded.Length + 32;
            return(encoded);
        }