C# equivalent to the PHP authentication required for Redirection

CSharpAuthenticationTest.cs

using System;
using System.IO;

namespace AuthenticationRedirection
{
    class Authentication
    {
        /**
        * Example of use, in your code you can ignore this function
        */
        static void Main(string[] args)
        {
            String login = "usuarioprueba";
            String tranKey = "ABCD1234";

            Authentication auth = new Authentication(login, tranKey);

            // Example of the values to use. YOU NEED TO CHANGE FOR YOUR OWN LOGIN AND TRANKEY
            System.Console.WriteLine("Login: " + auth.getLogin());
            System.Console.WriteLine("TranKey: " + auth.getTranKey());
            System.Console.WriteLine("Seed: " + auth.getSeed());
            System.Console.WriteLine("Nonce: " + auth.getNonce());

            // This is just a quick test, IGNORE IT
            String nonce = "WmEyvut9GgvcMWrV";
            String seed = "2016-08-30T16:21:35+00:00";
            auth.setNonce(nonce).setSeed(seed);
            if (auth.getTranKey().Equals("i/RFwSHAh8d7YgtO3HME5kCnYy8=") && auth.getNonce().Equals("V21FeXZ1dDlHZ3ZjTVdyVg=="))
            {
                System.Console.WriteLine("--- Quick test passed ---");
            }
            else
            {
                System.Console.WriteLine("--- Quick test FAILING ---");
            }

            Console.ReadLine();
        }

        String login;
        String tranKey;
        String seed;
        String nonce;

        public Authentication(String login, String tranKey)
        {
            this.login = login;
            this.tranKey = tranKey;
            Generate();
        }

        /**
         * Invoque this function each time that you use this class to generate a WS call
         * this will save the need to construct a new class every time
         */
        public Authentication Generate()
        {
            nonce = (new Random()).GetHashCode().ToString();
            seed = (DateTime.Now).ToString("yyyy-MM-ddTHH:mm:sszzz");
            return this;
        }

        public String getLogin()
        {
            return this.login;
        }

        public String getTranKey()
        {
            return Base64(ToSha1(nonce + seed + tranKey));
        }

        public String getSeed()
        {
            return this.seed;
        }

        public String getNonce()
        {
            return Base64(nonce);
        }

        public Authentication setNonce(String nonce)
        {
            this.nonce = nonce;
            return this;
        }

        public Authentication setSeed(String seed)
        {
            this.seed = seed;
            return this;
        }

        static public String Base64(byte[] input)
        {
            return System.Convert.ToBase64String(input);
        }

        static public String Base64(String input)
        {
            if (input != null)
            {
                return System.Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(input));
            }
            return "";
        }

        static public byte[] ToSha1(String text)
        {
            System.Security.Cryptography.SHA1 hashString = new System.Security.Cryptography.SHA1CryptoServiceProvider();
            return hashString.ComputeHash(ToStream(text));
        }

        static public Stream ToStream(String text)
        {
            MemoryStream stream = new MemoryStream();
            StreamWriter sw = new StreamWriter(stream);
            sw.Write(text);
            sw.Flush();
            stream.Position = 0;
            return stream;
        }

    }
}