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Encrypt an XML document using an asymmetric key

using System; using System.Xml; using System.Security.Cryptography; using System.Security.Cryptography.Xml; class Program {     static void Main(string[] args)     {         XmlDocument xmlDoc = new XmlDocument();         xmlDoc.Load("test.xml");         RSA rsaKey = new RSACryptoServiceProvider();         Encrypt(xmlDoc, "creditcard", rsaKey, "rsaKey");         Console.WriteLine(xmlDoc.OuterXml);         xmlDoc.Save("test.xml");         Decrypt(xmlDoc, rsaKey, "rsaKey");         xmlDoc.Save("test.xml");         Console.WriteLine(xmlDoc.OuterXml);         rsaKey.Clear();     }     public static void Encrypt(XmlDocument Doc, string ElementToEncrypt, RSA Alg, string KeyName)     {         XmlElement elementToEncrypt = Doc.GetElementsByTagName(ElementToEncrypt)[0] as XmlElement;         RijndaelManaged sessionKey = new RijndaelManaged();         sessionKey.KeySize = 256;         EncryptedXml eXml = new EncryptedXml();         byte[] encryptedElement = eXml.EncryptData(elementToEncrypt, sessionKey, false);         EncryptedData edElement = new EncryptedData();         edElement.Type = EncryptedXml.XmlEncElementUrl;         edElement.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncAES256Url);         EncryptedKey ek = new EncryptedKey();         byte[] encryptedKey = EncryptedXml.EncryptKey(sessionKey.Key, Alg, false);         ek.CipherData = new CipherData(encryptedKey);         ek.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncRSA15Url);         edElement.KeyInfo = new KeyInfo();         KeyInfoName kin = new KeyInfoName();         kin.Value = KeyName;         ek.KeyInfo.AddClause(kin);         edElement.KeyInfo.AddClause(new KeyInfoEncryptedKey(ek));         edElement.CipherData.CipherValue = encryptedElement;         EncryptedXml.ReplaceElement(elementToEncrypt, edElement, false);     }     public static void Decrypt(XmlDocument Doc, RSA Alg, string KeyName)     {         EncryptedXml exml = new EncryptedXml(Doc);         exml.AddKeyNameMapping(KeyName, Alg);         exml.DecryptDocument();     } }