Opc.Ua.WindowsCertificateStore.GetThumbprint C# (CSharp) Method

        private static string GetThumbprint(IntPtr pCertContext)
        {
            IntPtr pData = IntPtr.Zero;
            int dwDataSize = 0;

            try
            {
                if (pCertContext == IntPtr.Zero)
                {
                    return String.Empty;
                }

                int bResult = NativeMethods.CertGetCertificateContextProperty(
                    pCertContext,
                    CERT_SHA1_HASH_PROP_ID,
                    IntPtr.Zero,
                    ref dwDataSize);

                if (bResult == 0)
                {
                    int dwError = Marshal.GetLastWin32Error();

                    if (dwError != ERROR_MORE_DATA)
                    {
                        throw ServiceResultException.Create(
                            StatusCodes.BadUnexpectedError,
                            "Could not get the size of the thumbprint from the certificate context. Error={0:X8}",
                            dwError);
                    }
                }

                pData = Marshal.AllocHGlobal(dwDataSize);

                bResult = NativeMethods.CertGetCertificateContextProperty(
                   pCertContext,
                   CERT_SHA1_HASH_PROP_ID,
                   pData,
                   ref dwDataSize);

                if (bResult == 0)
                {
                    int dwError = Marshal.GetLastWin32Error();

                    throw ServiceResultException.Create(
                        StatusCodes.BadUnexpectedError,
                        "Could not get the thumbprint from the certificate context. Error={0:X8}",
                        dwError);
                }

                byte[] thumprint = new byte[dwDataSize];
                Marshal.Copy(pData, thumprint, 0, thumprint.Length);
                return Utils.ToHexString(thumprint).ToUpperInvariant();
            }
            finally
            {
                if (pData != IntPtr.Zero)
                {
                    Marshal.FreeHGlobal(pData);
                }
            }
        }