function SRP(remote, session)
{
  var srp = this;
  session = session || new this.Session();
  remote = remote || new this.Remote();
  remote.onError = remote.onError || this.error;
  session.onError = session.onError || this.error;
  this.remote = remote;
  this.session = session;

  // Start the login process by identifying the user
  this.identify = function()
  {
    remote.handshake(session, receive_salts);

    // Receive login salts from the server, start calculations
    function receive_salts(response)
    {
      // B = 0 will make the algorithm always succeed
      // -> refuse such a server answer
      if(response.B == 0) {
        srp.error("Server send random number 0 - this is not allowed");
      } else {
        session.calculations(response.s, response.B);
        remote.authenticate(session, confirm_authentication)
      }
    };

    // Receive M2 from the server and verify it
    // If an error occurs, raise it as an alert.
    function confirm_authentication(response)
    {
      if (session.validate(response.M))
        srp.success();
      else
        srp.error("Server key does not match");
    };
  };

  // Initiate the registration process
  this.register = function()
  {
    remote.register(session, srp.registered_user);
  };

  // The user has been registered successfully, now login
  this.registered_user = function(response)
  {
    if(response.ok)
    {
      srp.identify();
    }
  };  

  // Minimal error handling - set remote.onError to sth better to overwrite.
  this.error = function(text)
  {
    alert(text);
  };

  // This function is called when authentication is successful.
  // Developers can set this to other functions in specific implementations
  // and change the functionality.
  this.success = function()
  {
    var forward_url = document.getElementById("srp_forward").value;
    if(forward_url.charAt(0) != "#")
      window.location = forward_url;
    else
    {
      window.location = forward_url;
      alert("Login successful.");
    }
  };
};