KeyInfo key = new KeyInfo();
			key.AddClause(new KeyInfoX509Data(cert));

			SignedXml signedXml = new SignedXml(doc);
			
			signedXml.SigningKey = cert.PrivateKey;
			signedXml.KeyInfo = key;

			Reference refNode = new Reference();
			refNode.Uri = $"#{forSignNodeId}";
			refNode.DigestMethod = CPSignedXml.XmlDsigGost3411_2012_256Url;
			refNode.AddTransform(new XmlDsigExcC14NTransform());
			refNode.AddTransform(new XmlDsigSmevTransform());
			signedXml.AddReference(refNode);

			signedXml.SafeCanonicalizationMethods.Add("urn://smev-gov-ru/xmldsig/transform");
			signedXml.SignedInfo.CanonicalizationMethod = SignedXml.XmlDsigExcC14NTransformUrl;
			signedXml.SignedInfo.SignatureMethod = CPSignedXml.XmlDsigGost3410_2012_256Url;

			signedXml.ComputeSignature();

			XmlElement xmlDigitalSignature = signedXml.GetXml();

			ContentInfo contentInfo = new ContentInfo(fileContent);
			CmsSigner cmsSigner = new CmsSigner(cert);

			SignedCms signedCms = new SignedCms(contentInfo, true);

			signedCms.ComputeSignature(cmsSigner);

			return signedCms.Encode();