A Basic authentication module that uses UTF-8 to encode username and password (rather than ANSI for the built-in implementation)

BasicAuthenticationModule.cs

using System;
using System.Linq;
using System.Net;
using System.Text;
using Sharebox.Utils.Collections;

namespace Sharebox.Communication
{
    class BasicAuthenticationModule : IAuthenticationModule
    {
        public static bool ReplaceDefault()
        {
            var basicClient = AuthenticationManager.RegisteredModules.AsEnumerable()
                .OfType<IAuthenticationModule>()
                .FirstOrDefault(m => m.AuthenticationType == "Basic");

            if (basicClient != null && !(basicClient is BasicAuthenticationModule))
            {
                AuthenticationManager.Unregister(basicClient);
                AuthenticationManager.Register(new BasicAuthenticationModule(basicClient));
                return true;
            }
            return false;
        }

        private readonly IAuthenticationModule _basicClient;

        public BasicAuthenticationModule(IAuthenticationModule basicClient)
        {
            _basicClient = basicClient;
        }

        public Authorization Authenticate(string challenge, WebRequest request, ICredentials credentials)
        {
            var auth = _basicClient.Authenticate(challenge, request, credentials);
            return FixEncoding(auth);
        }

        public Authorization PreAuthenticate(WebRequest request, ICredentials credentials)
        {
            var auth = _basicClient.PreAuthenticate(request, credentials);
            return FixEncoding(auth);
        }

        // The default Basic auth module encodes the username/password in ANSI
        // Change it to use UTF-8 instead
        private Authorization FixEncoding(Authorization auth)
        {
            const string prefix = "Basic ";
            if (auth != null && auth.Complete && auth.Message != null && auth.Message.StartsWith(prefix, StringComparison.InvariantCultureIgnoreCase))
            {
                try
                {
                    var bytes = Convert.FromBase64String(auth.Message.Substring(prefix.Length));
                    string userAndPass = Encoding.Default.GetString(bytes);
                    bytes = Encoding.UTF8.GetBytes(userAndPass);
                    string message = prefix + Convert.ToBase64String(bytes);
                    auth = new Authorization(message, auth.Complete, auth.ConnectionGroupId);
                }
                catch(FormatException)
                {
                }
            }
            return auth;
        }

        public bool CanPreAuthenticate { get { return true; } }
        public string AuthenticationType { get { return "Basic"; } }

    }
}