Opc.Ua.CertificateIdentifier.Find C# (CSharp) Method

        public static X509Certificate2 Find(X509Certificate2Collection collection, string thumbprint, string subjectName, bool needPrivateKey)
        {
            // find by thumbprint.
            if (!String.IsNullOrEmpty(thumbprint))
            {
                collection = collection.Find(X509FindType.FindByThumbprint, thumbprint, false);

                foreach (X509Certificate2 certificate in collection)
                {
                    if (!needPrivateKey || certificate.HasPrivateKey)
                    {
                        if (String.IsNullOrEmpty(subjectName))
                        {
                            return certificate;
                        }

                        List<string> subjectName2 = Utils.ParseDistinguishedName(subjectName);

                        if (Utils.CompareDistinguishedName(certificate, subjectName2))
                        {
                            return certificate;
                        }
                    }
                }

                return null;
            }
            // find by subject name.
            if (!String.IsNullOrEmpty(subjectName))
            {
                List<string> subjectName2 = Utils.ParseDistinguishedName(subjectName);

                foreach (X509Certificate2 certificate in collection)
                {
                    if (Utils.CompareDistinguishedName(certificate, subjectName2))
                    {
                        if (!needPrivateKey || certificate.HasPrivateKey)
                        {
                            return certificate;
                        }
                    }
                }

                collection = collection.Find(X509FindType.FindBySubjectName, subjectName, false);

                foreach (X509Certificate2 certificate in collection)
                {
                    if (!needPrivateKey || certificate.HasPrivateKey)
                    {
                        return certificate;
                    }
                }
            }

            // certificate not found.
            return null;
        }

        /// <summary>
        /// Returns the issuers for the certificate.
        /// </summary>
        /// <param name="certificate">The certificate.</param>
        /// <param name="issuers">The issuers.</param>
        /// <returns></returns>
        public async Task <bool> GetIssuers(X509Certificate2 certificate, List <CertificateIdentifier> issuers)
        {
            bool isTrusted = false;
            CertificateIdentifier issuer = null;

            do
            {
                issuer = await GetIssuer(certificate, m_trustedCertificateList, m_trustedCertificateStore, true);

                if (issuer == null)
                {
                    issuer = await GetIssuer(certificate, m_issuerCertificateList, m_issuerCertificateStore, true);
                }
                else
                {
                    isTrusted = true;
                }

                if (issuer != null)
                {
                    issuers.Add(issuer);
                    certificate = await issuer.Find(false);

                    // check for root.
                    if (Utils.CompareDistinguishedName(certificate.Subject, certificate.Issuer))
                    {
                        break;
                    }
                }
            }while (issuer != null);

            return(isTrusted);
        }