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+/*
+ * cryptoHelpers.js: implements AES - Advanced Encryption Standard
+ * from the SlowAES project, http://code.google.com/p/slowaes/
+ *
+ * Copyright (c) 2008 Josh Davis ( http://www.josh-davis.org ),
+ * Mark Percival ( http://mpercival.com ),
+ * Johan Sundstrom ( http://ecmanaut.blogspot.com ),
+ * John Resig ( http://ejohn.org )
+ *
+ * Licensed under the Apache License, Version 2.0
+ * http://www.apache.org/licenses/
+ */
+
+
+
+var cryptoHelpers = {
+
+ // encodes a unicode string to UTF8 (8 bit characters are critical to AES functioning properly)
+ encode_utf8:function(s)
+ {
+ try{return unescape(encodeURIComponent(s));}
+ catch(e){throw 'error during utf8 encoding: cryptoHelpers.encode_utf8.';}
+ },
+
+
+ // decodes a UTF8 string back to unicode
+ decode_utf8:function(s)
+ {
+ try{return decodeURIComponent(escape(s));}
+ catch(e){throw('error during utf8 decoding: cryptoHelpers.decode_utf8.');}
+ },
+
+ //convert a number array to a hex string
+ toHex:function()
+ {
+ var array = [];
+ if(arguments.length == 1 && arguments[0].constructor == Array)
+ array = arguments[0];
+ else
+ array = arguments;
+ var ret = '';
+ for(var i = 0;i < array.length;i++)
+ ret += (array[i] < 16 ? '0' : '') + array[i].toString(16);
+ return ret.toLowerCase();
+ },
+
+ //convert a hex string to a number array
+ toNumbers:function(s)
+ {
+ var ret = [];
+ s.replace(/(..)/g,function(s){
+ ret.push(parseInt(s,16));
+ });
+ return ret;
+ },
+
+ // get a random number in the range [min,max]
+ getRandom:function(min,max)
+ {
+ if(min === null)
+ min = 0;
+ if(max === null)
+ max = 1;
+ return Math.floor(Math.random()*(max+1)) + min;
+ },
+
+ generateSharedKey:function(len)
+ {
+ if(len === null)
+ len = 16;
+ var key = [];
+ for(var i = 0; i < len*2; i++)
+ key.push(this.getRandom(0,255));
+ return key;
+ },
+
+ generatePrivateKey:function(s,size)
+ {
+ var sha = jsHash.sha2.arr_sha256(s);
+ return sha.slice(0,size);
+ },
+
+ convertStringToByteArray: function(s)
+ {
+ var byteArray = [];
+ for(var i = 0;i < s.length;i++)
+ {
+ byteArray.push(s.charCodeAt(i));
+ }
+ return byteArray;
+ },
+
+ convertByteArrayToString: function(byteArray)
+ {
+ var s = '';
+ for(var i = 0;i < byteArray.length;i++)
+ {
+ s += String.fromCharCode(byteArray[i]);
+ }
+ return s;
+ },
+
+ base64: {
+ // Takes a Nx16x1 byte array and converts it to Base64
+
+ chars: [
+ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+ 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+ 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
+ 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+ 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
+ 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
+ 'w', 'x', 'y', 'z', '0', '1', '2', '3',
+ '4', '5', '6', '7', '8', '9', '+', '/',
+ '=' // for decoding purposes
+ ],
+
+ encode_line: function(flatArr){
+ var b64 = '';
+
+ for (var i = 0; i < flatArr.length; i += 3){
+ b64 += this.chars[flatArr[i] >> 2];
+ b64 += this.chars[((flatArr[i] & 3) << 4) | (flatArr[i + 1] >> 4)];
+ if (!(flatArr[i + 1] === null)){
+ b64 += this.chars[((flatArr[i + 1] & 15) << 2) | (flatArr[i + 2] >> 6)];
+ }else{
+ b64 += '=';
+ }
+ if (!(flatArr[i + 2] === null)){
+ b64 += this.chars[flatArr[i + 2] & 63];
+ }else{
+ b64 += '=';
+ }
+ }
+ return b64;
+ },
+
+ encode: function(flatArr)
+ {
+ var b64 = this.encode_line(flatArr);
+ // OpenSSL is super particular about line breaks
+ var broken_b64 = b64.slice(0, 64) + '\n';
+ for (var i = 1; i < (Math.ceil(b64.length / 64)); i++)
+ {
+ broken_b64 += b64.slice(i * 64, i * 64 + 64) + (Math.ceil(b64.length / 64) == i + 1 ? '': '\n');
+ }
+ return broken_b64;
+ },
+
+ decode: function(string)
+ {
+ string = string.replace(/[\r\n\t ]+/g, '') + '===='; // drop all whitespaces and pad with '=' (end of b64 marker)
+ var flatArr = [];
+ var c = [];
+ //var b = [];
+ for (var i = 0; true ; i = i + 4){
+ c[0] = this.chars.indexOf(string.charAt(i));
+ if(c[0] == 64){
+ return flatArr;
+ }
+ c[1] = this.chars.indexOf(string.charAt(i + 1));
+ c[2] = this.chars.indexOf(string.charAt(i + 2));
+ c[3] = this.chars.indexOf(string.charAt(i + 3));
+
+ if(
+ (c[0] < 0) || // char1 is wrong
+ (c[1] < 0) || (c[1] == 64) || // char2 is wrong
+ (c[2] < 0) || // char3 is neither an valid char nor '='
+ (c[3] < 0) // char4 is neither an valid char nor '='
+ ){
+ throw 'error during base64 decoding at pos '+i+': cryptoHelpers.base64.decode.';
+ }
+
+ flatArr.push((c[0] << 2) | (c[1] >> 4));
+ if(c[2] >= 0 && c[2] < 64){
+ flatArr.push(((c[1] & 15) << 4) | (c[2] >> 2));
+ if(c[3] >= 0 && c[2] < 64){
+ flatArr.push(((c[2] & 3) << 6) | c[3]);
+ }
+ }
+ }
+ }
+ }
+};
+