.NET签名的XML前缀

using System;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Xml;

public class XmlDigitalSignature
{
    public static void SignXml(string xmlFilePath, string signedXmlFilePath, RSA privateKey)
    {
        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.Load(xmlFilePath);

        SignedXml signedXml = new SignedXml(xmlDoc);
        signedXml.SigningKey = privateKey;

        Reference reference = new Reference();
        reference.Uri = "";
        reference.AddTransform(new XmlDsigEnvelopedSignatureTransform());
        reference.AddTransform(new XmlDsigC14NTransform());
        signedXml.AddReference(reference);

        KeyInfo keyInfo = new KeyInfo();
        keyInfo.AddClause(new RSAKeyValue((RSA)privateKey));
        signedXml.KeyInfo = keyInfo;

        signedXml.ComputeSignature();

        XmlElement xmlDigitalSignature = signedXml.GetXml();
        xmlDoc.DocumentElement.AppendChild(xmlDoc.ImportNode(xmlDigitalSignature, true));

        xmlDoc.Save(signedXmlFilePath);
    }

    public static bool VerifyXml(string signedXmlFilePath, RSA publicKey)
    {
        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.Load(signedXmlFilePath);

        SignedXml signedXml = new SignedXml(xmlDoc);
        XmlNodeList nodeList = xmlDoc.GetElementsByTagName("Signature");
        signedXml.LoadXml((XmlElement)nodeList[0]);

        return signedXml.CheckSignature(publicKey);
    }
}