Class for Stack Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Runtime.Serialization;

namespace Hachette.Common.CustomConfigSections
{
    /// <summary>
    /// Represents a userName and password in the app.config, which will be used by <see cref="AppSettings.cs"/>
    /// to encrypt/decrypt.
    /// </summary>
    public class EncryptedUserCredential : ConfigurationElement
    {
        [ConfigurationProperty("userName", IsRequired = true)]
        public string UserName
        {
            get
            {
                return this["userName"] as string;
            }
        }

        [ConfigurationProperty("password", IsRequired = true)]
        public string Password
        {
            get
            {
                return this["password"] as string;
            }
        }
    }

    public class EncryptedUserCredentials : ConfigurationElementCollection
    {
        public EncryptedUserCredential this[int index]
        {
            get
            {
                return base.BaseGet(index) as EncryptedUserCredential;
            }
            set
            {
                if (base.BaseGet(index) != null)
                {
                    base.BaseRemoveAt(index);
                }
                this.BaseAdd(index, value);
            }
        }

        public new EncryptedUserCredential this[string responseString]
        {
            get
            {
                return (EncryptedUserCredential)BaseGet(responseString);
            }
            set
            {
                if (BaseGet(responseString) != null)
                {
                    BaseRemoveAt(BaseIndexOf(BaseGet(responseString)));
                }
                BaseAdd(value);
            }
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new EncryptedUserCredential();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((EncryptedUserCredential)element).UserName;
        }
    }



    public class RegisterEncryptedUserCredentialsConfig : ConfigurationSection
    {
        public static RegisterEncryptedUserCredentialsConfig GetConfig()
        {
            //var config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

            return (RegisterEncryptedUserCredentialsConfig)System.Configuration.ConfigurationManager.GetSection("EncryptedUserCredentials") ?? new RegisterEncryptedUserCredentialsConfig();
        }

        [System.Configuration.ConfigurationProperty("EncryptedUserCredentials", IsDefaultCollection=true,IsRequired=true)]
        [ConfigurationCollection(typeof(EncryptedUserCredentials), AddItemName="EncryptedUserCredential")]
        public EncryptedUserCredentials EncryptedUserCredentials
        {
            get
            {
                object o = this["EncryptedUserCredentials"];
                return o as EncryptedUserCredentials;
            }


        }

    }



}