var sgn = new PdfPKCS7(null, new[] {cert}, "SHA1", false);
                Stream data = sap.GetRangeStream();

                HashAlgorithm myhash = HashAlgorithm.Create("GOST3411");
                byte[] messageHash = myhash.ComputeHash(data);
                
                var now = DateTime.Now;
                signaturedto = new SignatureDTO
                {
                    Hash = messageHash,
                    AuthenticatedAttributeBytes = sgn.getAuthenticatedAttributeBytes(messageHash, now, null, null, CryptoStandard.CADES),
                    Now = now,
                    SignatureAppearance = sap,
                    Sign = sgn,
                    Stream = os
                };

   
                ClassPass.Result.Sign.SetExternalDigest(newArray, null, "RSA");
                byte[] encodedSig = ClassPass.Result.Sign.GetEncodedPKCS7(ClassPass.Result.Hash, ClassPass.Result.Now, null, null, null, CryptoStandard.CADES);
                byte[] paddedSig = new byte[8192];
                Array.Copy(encodedSig, 0, paddedSig, 0, encodedSig.Length);
                PdfDictionary pdfDic = new PdfDictionary();
                pdfDic.Put(PdfName.CONTENTS, new PdfString(paddedSig).SetHexWriting(true));
                ClassPass.Result.SignatureAppearance.Close(pdfDic);
                result = "Файл подписанного отношения сформирован и сохранен";
                return result;