Components to generate secure tokens to be created by a secure web service to use for authentication of subsequent calls. It essentially operates on the same premise of a remember me cookie in forms authentication. The token expiration should use configured values instead of hard coding... This example uses JSON .NET to serialize objects into js…

IStringSerializer.cs

public interface IStringSerializer
{
    T Deserialize<T>(string item);
    string Serialize(object item);
}

ITokenProvider.cs

public interface ITokenProvider
{
    string GenerateToken<T>(TokenInfo<T> data);
    TokenInfo<T> ParseToken<T>(string token);
}

JsonSerializer.cs

public class JsonSerializer : IStringSerializer
{
    public T Deserialize<T>(string item)
    {
        return JsonConvert.DeserializeObject<T>(item);
    }


    public string Serialize(object item)
    {
        return JsonConvert.SerializeObject(item);
    }
}

SecurityTokenProvider.cs

public class SecurityTokenProvider : ITokenProvider
{
    private readonly IStringSerializer _serializer;

    public SecurityTokenProvider(IStringSerializer serializer)
    {
        if (serializer == null) throw new ArgumentNullException("serializer");

        _serializer = serializer;
    }

    public string GenerateToken<T>(TokenInfo<T> data)
    {
        FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(
            1,
            data.UserName,
            DateTime.Now,
            DateTime.Now.AddMinutes(20),
            false,
            _serializer.Serialize(data.UserData)
        );
        string token = FormsAuthentication.Encrypt(ticket);

        return token;
    }

    public TokenInfo<T> ParseToken<T>(string token)
    {
        FormsAuthenticationTicket ticket = FormsAuthentication.Decrypt(token);
        if (ticket != null)
        {
            var userData = _serializer.Deserialize<T>(ticket.UserData);
            var info = new TokenInfo<T>
            {
                UserName = ticket.Name,
                UserData = userData
            };

            return info;
        }

        // Null ticket = invalid token
        throw new InvalidOperationException();
    }
}

TokenInfo.cs

public class TokenInfo<T>
{
    public string UserName { get; set; }
    public T UserData { get; set; }
}