Encrypting appSettings and connectionStrings sections in web.config :
 
   aspnet_regiis.exe –pef "appSettings" "<Path.to.website.directory>"
 
   aspnet_regiis.exe –pef "connectionStrings" "<Path.to.website.directory>"
 
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Encrypting appSettings and connectionStrings sections in web.config and specifying the Data Protection Provider:

To Encrypt, run the following from the Visual Studio command prompt:
 
  aspnet_regiis -pe "connectionStrings" -app "/AppName" -prov "RsaProtectedConfigurationProvider"
 
To Decrypt, run the following from the Visual Studio command prompt:
 
  aspnet_regiis -pd "connectionStrings" -app "/AppName"
 

using System;
using System.Security.Cryptography;
 
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string PlainText = "Luciano Evaristo Guerche";

namespace SignAndEncryptXmlDocumentConsoleApplication
{
    using System;
    using System.IO;
    using System.Security.Cryptography;
    using System.Security.Cryptography.Xml;
    using System.Xml;
 
    class Program
    {