package com.gsolo.encryption {

	public class SHA1 {

		/*

		 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined

		 * in FIPS PUB 180-1

		 * Version 2.1a Copyright Paul Johnston 2000 - 2002.

		 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet

		 * Distributed under the BSD License

		 * See http://pajhome.org.uk/crypt/md5 for details.

		 *

		 * Converted to AS3 By Geoffrey Williams

		 */

		/*

		 * Configurable variables. You may need to tweak these to be compatible with

		 * the server-side, but the defaults work in most cases.

		 */

		public static const HEX_FORMAT_LOWERCASE:uint = 0;

		public static const HEX_FORMAT_UPPERCASE:uint = 1;

		public static const BASE64_PAD_CHARACTER_DEFAULT_COMPLIANCE:String = "";

		public static const BASE64_PAD_CHARACTER_RFC_COMPLIANCE:String = "=";

		public static const BITS_PER_CHAR_ASCII:uint = 8;

		public static const BITS_PER_CHAR_UNICODE:uint = 8;

		public static var hexcase:uint = 0;  /* hex output format. 0 - lowercase; 1 - uppercase        */

		public static var b64pad:String  = ""; /* base-64 pad character. "=" for strict RFC compliance   */

		public static var chrsz:uint   = 8;  /* bits per input character. 8 - ASCII; 16 - Unicode      */

		public static function encrypt (string:String):String {

			return hex_sha1 (string);

		}

		/*

		 * These are the functions you'll usually want to call

		 * They take string arguments and return either hex or base-64 encoded strings

		 */

		public static function hex_sha1 (string:String):String {

			return binb2hex (core_sha1( str2binb(string), string.length * chrsz));

		}

		public static function b64_sha1 (string:String):String {

			return binb2b64 (core_sha1 (str2binb (string), string.length * chrsz));

		}

		public static function str_sha1 (string:String):String {

			return binb2str (core_sha1 (str2binb (string), string.length * chrsz));

		}

		public static function hex_hmac_sha1 (key:String, data:String):String {

			return binb2hex (core_hmac_sha1 (key, data));

		}

		public static function b64_hmac_sha1 (key:String, data:String):String {

			return binb2b64 (core_hmac_sha1 (key, data));

		}

		public static function str_hmac_sha1 (key:String, data:String):String {

			return binb2str (core_hmac_sha1 (key, data));

		}

		/*

		 * Perform a simple self-test to see if the VM is working

		 */

		public static function sha1_vm_test ():Boolean {

		  return hex_sha1 ("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";

		}

		/*

		 * Calculate the SHA-1 of an array of big-endian words, and a bit length

		 */

		public static function core_sha1 (x:Array, len:Number):Array {

			/* append padding */

			x[len >> 5] |= 0x80 << (24 - len % 32);

			x[((len + 64 >> 9) << 4) + 15] = len;

			var w:Array = new Array(80);

			var a:Number =  1732584193;

			var b:Number = -271733879;

			var c:Number = -1732584194;

			var d:Number =  271733878;

			var e:Number = -1009589776;

			for(var i:Number = 0; i < x.length; i += 16) {

				var olda:Number = a;

				var oldb:Number = b;

				var oldc:Number = c;

				var oldd:Number = d;

				var olde:Number = e;

				for(var j:Number = 0; j < 80; j++) {

					if(j < 16) w[j] = x[i + j];

				     else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);

					var t:Number = safe_add (safe_add (rol (a, 5), sha1_ft (j, b, c, d)), safe_add (safe_add (e, w[j]), sha1_kt (j)));

					e = d;

					d = c;

					c = rol(b, 30);

					b = a;

					a = t;

				}

				a = safe_add(a, olda);

				b = safe_add(b, oldb);

				c = safe_add(c, oldc);

				d = safe_add(d, oldd);

				e = safe_add(e, olde);

			}

			return [a, b, c, d, e];

		}

		/*

		 * Perform the appropriate triplet combination function for the current

		 * iteration

		 */

		public static function sha1_ft (t:Number, b:Number, c:Number, d:Number):Number {

			if(t < 20) return (b & c) | ((~b) & d);

			if(t < 40) return b ^ c ^ d;

			if(t < 60) return (b & c) | (b & d) | (c & d);

			return b ^ c ^ d;

		}

		/*

		 * Determine the appropriate additive constant for the current iteration

		 */

		public static function sha1_kt (t:Number):Number {

			return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 : (t < 60) ? -1894007588 : -899497514;

		}

		/*

		 * Calculate the HMAC-SHA1 of a key and some data

		 */

		public static function core_hmac_sha1 (key:String, data:String):Array {

		  var bkey:Array = str2binb (key);

		  if (bkey.length > 16) bkey = core_sha1 (bkey, key.length * chrsz);

		  var ipad:Array = new Array(16), opad:Array = new Array(16);

		  for(var i:Number = 0; i < 16; i++) {

			ipad[i] = bkey[i] ^ 0x36363636;

			opad[i] = bkey[i] ^ 0x5C5C5C5C;

		  }

		  var hash:Array = core_sha1 (ipad.concat (str2binb(data)), 512 + data.length * chrsz);

		  return core_sha1 (opad.concat (hash), 512 + 160);

		}

		/*

		 * Add integers, wrapping at 2^32. This uses 16-bit operations internally

		 * to work around bugs in some JS interpreters.

		 */

		public static function safe_add (x:Number, y:Number):Number {

			var lsw:Number = (x & 0xFFFF) + (y & 0xFFFF);

			var msw:Number = (x >> 16) + (y >> 16) + (lsw >> 16);

			return (msw << 16) | (lsw & 0xFFFF);

		}

		/*

		 * Bitwise rotate a 32-bit number to the left.

		 */

		public static function rol (num:Number, cnt:Number):Number {

			return (num << cnt) | (num >>> (32 - cnt));

		}

		/*

		 * Convert an 8-bit or 16-bit string to an array of big-endian words

		 * In 8-bit function, characters >255 have their hi-byte silently ignored.

		 */

		public static function str2binb (str:String):Array {

		  var bin:Array = new Array ();

		  var mask:Number = (1 << chrsz) - 1;

		  for (var i:Number = 0; i < str.length * chrsz; i += chrsz) bin[i>>5] |= (str.charCodeAt (i / chrsz) & mask) << (32 - chrsz - i%32);

		  return bin;

		}

		/*

		 * Convert an array of big-endian words to a string

		 */

		public static function binb2str (bin:Array):String {

			var str:String = "";

			var mask:Number = (1 << chrsz) - 1;

			for (var i:Number = 0; i < bin.length * 32; i += chrsz) str += String.fromCharCode((bin[i>>5] >>> (32 - chrsz - i%32)) & mask);

			return str;

		}

		/*

		 * Convert an array of big-endian words to a hex string.

		 */

		public static function binb2hex (binarray:Array):String {

			var hex_tab:String = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";

			var str:String = "";

			for(var i:Number = 0; i < binarray.length * 4; i++) {

			str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) +

			          hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8  )) & 0xF);

			}

			return str;

		}

		/*

		 * Convert an array of big-endian words to a base-64 string

		 */

		public static function binb2b64 (binarray:Array):String {

			var tab:String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

			var str:String = "";

			for(var i:Number = 0; i < binarray.length * 4; i += 3) {

				var triplet:Number = (((binarray[i   >> 2] >> 8 * (3 -  i   %4)) & 0xFF) << 16)

		                | (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )

		                |  ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);

				for(var j:Number = 0; j < 4; j++) {

					if (i * 8 + j * 6 > binarray.length * 32) str += b64pad;

					else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);

				}

			}

			return str;

		}		

	}

}