iTextSharp.text.pdf.PdfEncryption.CreateDocumentId C# (CSharp) Метод

        public static byte[] CreateDocumentId()
        {
            long time = DateTime.Now.Ticks + Environment.TickCount;
            long mem = GC.GetTotalMemory(false);
            String s = time + "+" + mem + "+" + (seq++);
            byte[] b = Encoding.ASCII.GetBytes(s);
            return DigestAlgorithms.Digest("MD5", b);
        }

        /**
         * Generates an OCSP request using BouncyCastle.
         * @param issuerCert	certificate of the issues
         * @param serialNumber	serial number
         * @return	an OCSP request
         * @throws OCSPException
         * @throws IOException
         */
        private static OcspReq GenerateOCSPRequest(X509Certificate issuerCert, BigInteger serialNumber)
        {
            // Generate the id for the certificate we are looking for
            CertificateID id = new CertificateID(CertificateID.HashSha1, issuerCert, serialNumber);

            // basic request generation with nonce
            OcspReqGenerator gen = new OcspReqGenerator();

            gen.AddRequest(id);

            // create details for nonce extension
            ArrayList oids   = new ArrayList();
            ArrayList values = new ArrayList();

            oids.Add(OcspObjectIdentifiers.PkixOcspNonce);
            values.Add(new X509Extension(false, new DerOctetString(new DerOctetString(PdfEncryption.CreateDocumentId()).GetEncoded())));

            gen.SetRequestExtensions(new X509Extensions(oids, values));

            return(gen.Generate());
        }