如何在不使用 SignedXml 的情况下验证 c# 中的 xml 数字签名？

Question

如何在不使用 SignedXml（在 dotnet 核心中不可用）的情况下验证 xml 签名（用于 SOAP 请求）？

我正在尝试这样，但它总是给我错误：

 public static void CheckSignature(XElement responseXml, MyResponseType response)
    {
        string originalDigestValue = Convert.ToBase64String(response.Signature.SignedInfo.Reference.FirstOrDefault().DigestValue);
        var originalSignatureValue = response.Signature.SignatureValue.Value;

        X509DataType certificateData = (X509DataType)response.Signature.KeyInfo.Items[0];
        X509Certificate2 certificate = new X509Certificate2((byte[])certificateData.Items[0]);

        //for calculating digest value
        //responseXml.Descendants(nm + "Signature").SingleOrDefault().Remove();
        //var digestValue = Convert.ToBase64String(SHA1.Create().ComputeHash(System.Text.Encoding.UTF8.GetBytes(responseXml.Document.ToString())));

        XNamespace nm = @"http://www.w3.org/2000/09/xmldsig#";
        var signedInfoNode = responseXml.Descendants(nm + "SignedInfo").SingleOrDefault();

        var signedInfo = signedInfoNode.ToString().Trim();

        byte[] signedInfoBytes = Encoding.UTF8.GetBytes(signedInfo);

        var hash = SHA1.Create().ComputeHash(signedInfoBytes);

        RSA rsa = certificate.GetRSAPublicKey();

        try
        {
            Console.WriteLine("Signed Info: \n" + signedInfo);
            Console.WriteLine("Verification: \n" + rsa.VerifyData(signedInfoBytes, originalSignatureValue, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1));
            Console.WriteLine("Verification hash: \n" + rsa.VerifyData(hash, originalSignatureValue, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1));
        }
        catch (Exception exc)
        {
           //
        }
    }

Answer 1

xmldsig 是一个非常庞大、非常复杂的规范。如果您愿意，您可以尝试实现它，复杂的部分是将 XML 文档转换为字节以进行签名和验证（canonicalization (or c14n) spec 是独立的，而且很大）。

SignedXml 现在应该可以通过.NET Core 2.0 Preview 1 获得，升级绝对是您最容易的选择。