xml文档的加密与解密

//  要在工程里添加 System.Security 的引用集 
using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Xml; //XML Namespace 
using System.Security.Cryptography; 
using System.Security.Cryptography.Xml;//xml encryption namespace 
//using System.Windows.Forms; //Application namespace  
namespace ConsoleApplication1
{
    class mySignXML
    {
        //xml加密方法 
        private void Encrypt(XmlDocument Doc, string ElementName, SymmetricAlgorithm Key)
        {
            XmlElement elementToEncrypt = Doc.GetElementsByTagName(ElementName)[0] as XmlElement;
            EncryptedXml eXml = new EncryptedXml();
            byte[] encryptedElement = eXml.EncryptData(elementToEncrypt, Key, false);//最后一个参数不能为空???? 
            EncryptedData edElement = new EncryptedData();
            edElement.Type = EncryptedXml.XmlEncElementUrl;
            string encryptionMethod = null;
            if (Key is TripleDES)
            {
                encryptionMethod = EncryptedXml.XmlEncTripleDESUrl;
            }
            else if (Key is DES)
            {
                encryptionMethod = EncryptedXml.XmlEncDESUrl;
            }
            if (Key is Rijndael)
            {
                switch (Key.KeySize)
                {
                    case 128:
                        encryptionMethod = EncryptedXml.XmlEncAES128Url;
                        break;
                    case 192:
                        encryptionMethod = EncryptedXml.XmlEncAES192Url;
                        break;
                    case 256:
                        encryptionMethod = EncryptedXml.XmlEncAES256Url;
                        break;
                }
            }
            edElement.EncryptionMethod = new EncryptionMethod(encryptionMethod);
            edElement.CipherData.CipherValue = encryptedElement;
            EncryptedXml.ReplaceElement(elementToEncrypt, edElement, false);
        }
        //xml解密方法 
        private bool Decrypt(XmlDocument Doc, SymmetricAlgorithm Alg)
        {
            try
            {
                XmlElement encryptedElement = Doc.GetElementsByTagName("EncryptedData")[0] as XmlElement;
                EncryptedData edElement = new EncryptedData();
                edElement.LoadXml(encryptedElement);
                EncryptedXml exml = new EncryptedXml();
                byte[] rgbOutput = exml.DecryptData(edElement, Alg);
                exml.ReplaceData(encryptedElement, rgbOutput);
                return true;
            }
            catch (Exception e)
            {
                return false;
            }
        }


        //对相应xml文件 加密 
        public void fileEncryption()
        {
            RijndaelManaged key = new RijndaelManaged();
            //设置密钥:key为32位=数字或字母16个=汉字8个 
            byte[] byteKey = Encoding.Unicode.GetBytes("BFEBFBFF000106E5");//every load get time as key 
            key.Key = byteKey;
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.PreserveWhitespace = true;
            xmlDoc.Load("test.xml");//加载要加密的XML文件 
            Encrypt(xmlDoc, "cpuid", key);//需要加密的节点             
            if (key != null)
            {
                key.Clear();
            }
            xmlDoc.Save("test1.xml");//生成加密后的XML文件 
            //MessageBox.Show("OK");  
        }

        //对相应xml文件 解密 
        public void fileDcryption()         
        { 
            RijndaelManaged key = new RijndaelManaged(); 
            //设置密钥:key为32位=数字或字母16个=汉字8个 
            byte[] byteKey = Encoding.Unicode.GetBytes("2222222222222222");             
            key.Key = byteKey; 
            XmlDocument xmlDoc = new XmlDocument();             
            xmlDoc.PreserveWhitespace = true; 
            xmlDoc.Load("test1.xml");//加载要解密的XML文件 
            Decrypt(xmlDoc, key);             
            if (key != null)             
            { 
                key.Clear();             
            } 
            xmlDoc.Save("test2.xml");//生成解密后的XML文件 
            // MessageBox.Show("OK");         
        }     
    } 
} 

MSDN上提供的XML加密方法：

MSDN关于SignXML类的解释

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

namespace ConsoleApplication1
{

    public class SignXML
    {

        public static void Main(String[] args)
        {
            mySignXML mysignxml = new mySignXML();
           mysignxml.fileEncryption();
           mysignxml.fileDcryption();

           try
           {
               // Create a new CspParameters object to specify
               // a key container.
               CspParameters cspParams = new CspParameters();
               cspParams.KeyContainerName = "XML_DSIG_RSA_KEY";

               // Create a new RSA signing key and save it in the container. 
               RSACryptoServiceProvider rsaKey = new RSACryptoServiceProvider(cspParams);

               // Create a new XML document.
               XmlDocument xmlDoc = new XmlDocument();

               // Load an XML file into the XmlDocument object.
               xmlDoc.PreserveWhitespace = true;
               xmlDoc.Load("test.xml");

               // Sign the XML document. 
               SignXml(xmlDoc, rsaKey);

               Console.WriteLine("XML file signed.");

               // Save the document.
               xmlDoc.Save("test.xml");



           }
           catch (Exception e)
           {
               Console.WriteLine(e.Message);
           }
        }


        // Sign an XML file. 
        // This document cannot be verified unless the verifying 
        // code has the key with which it was signed.
        public static void SignXml(XmlDocument Doc, RSA Key)
        {
            // Check arguments.
            if (Doc == null)
                throw new ArgumentException("Doc");
            if (Key == null)
                throw new ArgumentException("Key");

            // Create a SignedXml object.
            SignedXml signedXml = new SignedXml(Doc);

            // Add the key to the SignedXml document.
            signedXml.SigningKey = Key;

            // Create a reference to be signed.
            Reference reference = new Reference();
            reference.Uri = "";

            // Add an enveloped transformation to the reference.
            XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
            reference.AddTransform(env);

            // Add the reference to the SignedXml object.
            signedXml.AddReference(reference);

            // Compute the signature.
            signedXml.ComputeSignature();

            // Get the XML representation of the signature and save
            // it to an XmlElement object.
            XmlElement xmlDigitalSignature = signedXml.GetXml();

            // Append the element to the XML document.
            Doc.DocumentElement.AppendChild(Doc.ImportNode(xmlDigitalSignature, true));

        }
    }
}