// prng4.js - uses Arcfour as a PRNG
// Copyright (c) 2005  Tom Wu
// All Rights Reserved.
// See "LICENSE" for details.
// Incapsulated by Francesco Sullo (www.sullof.com), december 2006

if (typeof JSBN != 'undefined') {

	JSBN.PRNG4 = {
	
		Arcfour: function () {
			this.i = 0;
			this.j = 0;
			this.S = new Array();
		
		// Initialize arcfour context from key, an array of ints, each from [0..255]
			this.init = function (key) {
			  var i, j, t;
			  for(i = 0; i < 256; ++i)
				this.S[i] = i;
			  j = 0;
			  for(i = 0; i < 256; ++i) {
				j = (j + this.S[i] + key[i % key.length]) & 255;
				t = this.S[i];
				this.S[i] = this.S[j];
				this.S[j] = t;
			  }
			  this.i = 0;
			  this.j = 0;
			};
	
			this.next = function () {
			  var t;
			  this.i = (this.i + 1) & 255;
			  this.j = (this.j + this.S[this.i]) & 255;
			  t = this.S[this.i];
			  this.S[this.i] = this.S[this.j];
			  this.S[this.j] = t;
			  return this.S[(t + this.S[this.i]) & 255];
			};
		}
		,
		
		// Plug in your RNG constructor here
		prng_newstate: function () {
			return new this.Arcfour();
		}
		,
		
		// Pool size must be a multiple of 4 and greater than 32.
		// An array of bytes the size of the pool will be passed to init()
		rng_psize: 256
	
	}
};