// SHA-1 Cryptographic Hash Algorithm 
// From http://www.movable-type.co.uk/
// Example: f.hash.value = getHashCode(f.message.value)
// Note SHA-1 hash of ¡®abc¡¯ should be ¡®a9993e364706816aba3e25717850c26c9cd0d89d¡¯
//
function getHashCode(msg){
    // constants [4.2.1]
    var K = new Array(0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6);

    // PREPROCESSING  
    msg += String.fromCharCode(0x80);  // add trailing '1' bit to string [5.1.1]

    // convert string msg into 512-bit/16-integer blocks arrays of ints [5.2.1]
    var l = Math.ceil(msg.length/4) + 2;  // long enough to contain msg plus 2-word length
    var N = Math.ceil(l/16);              // in N 16-int blocks
    var M = new Array(N);

    for (var i=0; i<N; i++) {
        M[i] = new Array(16);
        for (var j=0; j<16; j++) {  // encode 4 chars per integer, big-endian encoding
            M[i][j] = (msg.charCodeAt(i*64+j*4)<<24) | (msg.charCodeAt(i*64+j*4+1)<<16) | 
                      (msg.charCodeAt(i*64+j*4+2)<<8) | (msg.charCodeAt(i*64+j*4+3));
        } // note running off the end of msg is ok 'cos bitwise ops on NaN return 0
    }
    // add length (in bits) into final pair of 32-bit integers (big-endian) [5.1.1]
    M[N-1][14] = ((msg.length-1) >>> 30) * 8;
    M[N-1][15] = ((msg.length-1)*8) & 0xffffffff;

    // set initial hash value [5.3.1]
    var H0 = 0x67452301;
    var H1 = 0xefcdab89;
    var H2 = 0x98badcfe;
    var H3 = 0x10325476;
    var H4 = 0xc3d2e1f0;

    // HASH COMPUTATION [6.1.2]

    var W = new Array(80); var a, b, c, d, e;
    for (var i=0; i<N; i++) {
        // 1 - prepare message schedule 'W'
        for (var t=0;  t<16; t++) W[t] = M[i][t];
        for (var t=16; t<80; t++) W[t] = ROTL(W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16], 1);

        // 2 - initialise five working variables a, b, c, d, e with previous hash value
        a = H0; b = H1; c = H2; d = H3; e = H4;

        // 3 - main loop
        for (var t=0; t<80; t++) {
            var s = Math.floor(t/20); // seq for blocks of 'f' functions and 'K' constants
            T = (ROTL(a,5) + fHexStr(s,b,c,d) + e + K[s] + W[t]) & 0xffffffff;
            e = d;
            d = c;
            c = ROTL(b, 30);
            b = a;
            a = T;
        }

        // 4 - compute the new intermediate hash value
        H0 = (H0+a) & 0xffffffff;  // note 'addition modulo 2^32'
        H1 = (H1+b) & 0xffffffff; 
        H2 = (H2+c) & 0xffffffff; 
        H3 = (H3+d) & 0xffffffff; 
        H4 = (H4+e) & 0xffffffff;
    }
    return H0.toHexStr() + H1.toHexStr() + H2.toHexStr() + H3.toHexStr() + H4.toHexStr();
}

//
// function 'f' [4.1.1]
//
function fHexStr(s, x, y, z){
    switch(s) {
    case 0: return (x & y) ^ (~x & z);
    case 1: return x ^ y ^ z;
    case 2: return (x & y) ^ (x & z) ^ (y & z);
    case 3: return x ^ y ^ z;
    }
}

//
// rotate left (circular left shift) value x by n positions [3.2.5]
//
function ROTL(x, n){
    return (x<<n) | (x>>>(32-n));
}

//
// extend Number class with a tailored hex-string method 
//   (note toString(16) is implementation-dependant, and  
//   in IE returns signed numbers when used on full words)
//
Number.prototype.toHexStr = function(){
    var s="", v;
    for (var i=7; i>=0; i--) { v = (this>>>(i*4)) & 0xf; s += v.toString(16); }
    return s;
}


//
// 'Block' Tiny Encryption Algorithm
//
// Algorithm: David Wheeler & Roger Needham, Cambridge University Computer Lab
//            http://www.cl.cam.ac.uk/ftp/papers/djw-rmn/djw-rmn-tea.html (1994)
//            http://www.cl.cam.ac.uk/ftp/users/djw3/xtea.ps (1997)
//            http://www.cl.cam.ac.uk/ftp/users/djw3/xxtea.ps (1998)
//
// JavaScript implementation: Chris Veness, Movable Type Ltd: www.movable-type.co.uk
//
// Example:  f.encrypted.value = ciferText = encryptCode(f.val.value, f.key.value)
//			 f.decrypted.value = decryptCode(ciferText, f.key.value)
//
// encrypt: Use 128 bits (16 chars) of string 'key' to encrypt string 'val'
//          (note key & val must be strings not string objects)
//
// Return encrypted text as string
//
function encryptCode(val, key)
{
    // 'escape' val so chars outside ISO-8859-1 work in single-byte packing, but keep spaces as
    // spaces (not '%20') so encrypted text doesn't grow too long!
    var v = strToLongs(escape(val).replace(/%20/g,' '));
    var k = strToLongs(key.slice(0,16));
    var n = v.length;

    if (n == 0) return("");  // nothing to encrypt
    if (n == 1) v[n++] = 0;  // algorithm doesn't work for n<2 so fudge by adding nulls

    // TEA routine as per Wheeler & Needham, Oct 1998

    var z = v[n-1], y = v[0], delta = 0x9E3779B9;
    var mx, e, q = Math.floor(6 + 52/n), sum = 0;

    while (q-- > 0) {  // 6 + 52/n operations gives between 6 & 32 mixes on each word
        sum += delta;
        e = sum>>>2 & 3;
        for (var p = 0; p < n-1; p++) {
            y = v[p+1];
            mx = (z>>>5 ^ y<<2) + (y>>>3 ^ z<<4) ^ (sum^y) + (k[p&3 ^ e] ^ z)
            z = v[p] += mx;
        }
        y = v[0];
        mx = (z>>>5 ^ y<<2) + (y>>>3 ^ z<<4) ^ (sum^y) + (k[p&3 ^ e] ^ z)
        z = v[n-1] += mx;
    }

    // note: unsigned right-shift '>>>' is used in place of original '>>', due to lack of 
    // 'unsigned' type declaration in JavaScript (thanks to Karsten Kraus @ swr3 for this)

    return longsToStr(v);  // if control chars & nulls cause difficulties use: return(escape(longsToStr(v)));
}


//
// decrypt: use 128 bits of string 'key' to decrypt string 'val' encrypted as per above
//
function decryptCode(val, key)
{
    var v = strToLongs(val);  // if encrypt used escape(), use: var v = strToLongs(unescape(val));
    var k = strToLongs(key.slice(0,16));
    var n = v.length;

    if (n == 0) return("");

    // TEA routine as per Wheeler & Needham, Oct 1998

    var z = v[n-1], y = v[0], delta = 0x9E3779B9;
    var mx, e, q = Math.floor(6 + 52/n), sum = q*delta;

    while (sum != 0) {
        e = sum>>>2 & 3;
        for (var p = n-1; p > 0; p--) {
            z = v[p-1];
            mx = (z>>>5 ^ y<<2) + (y>>>3 ^ z<<4) ^ (sum^y) + (k[p&3 ^ e] ^ z)
            y = v[p] -= mx;
        }
        z = v[n-1];
        mx = (z>>>5 ^ y<<2) + (y>>>3 ^ z<<4) ^ (sum^y) + (k[p&3 ^ e] ^ z)
        y = v[0] -= mx;
        sum -= delta;
    }

    var s = longsToStr(v);
    if (s.indexOf("\x00") != -1) {
        // strip trailing null chars resulting from filling 4-char blocks
        s = s.substr(0, s.indexOf("\x00"));
    }

    return unescape(s);
}


function strToLongs(s) {  // convert string to array of longs, each containing 4 chars
    // note chars must be within ISO-8859-1 (with Unicode code-point < 256) to fit 4/long
    var l = new Array(Math.ceil(s.length/4))
    for (var i=0; i<l.length; i++) {
        // note little-endian encoding - endianness is irrelevant as long as 
        // it is the same in longsToStr() 
        l[i] = s.charCodeAt(i*4) + (s.charCodeAt(i*4+1)<<8) + 
               (s.charCodeAt(i*4+2)<<16) + (s.charCodeAt(i*4+3)<<24);
    }
    return l;  // note running off the end of the string generates nulls since 
}              // bitwise operators treat NaN as 0


function longsToStr(l) {  // convert array of longs back to string
    var a = new Array(l.length);
    for (var i=0; i<l.length; i++) {
        a[i] = String.fromCharCode(l[i] & 0xFF, l[i]>>>8 & 0xFF, 
                                   l[i]>>>16 & 0xFF, l[i]>>>24 & 0xFF);
    }
    return a.join('');  // use Array.join() rather than repeated string appends for efficiency
}


/* base64 Encoding/Decoding base64±àÂë/½âÂë 
 * http://www.51one.net  
 * 2005-04-15
 * For Example :
 * <textarea name="theText" cols="40" rows="6"></textarea><br>
 * <input type="button" name="encode" value="Encode to base64"
	onClick="document.base64Form.theText.value=encode64(document.base64Form.theText.value);">
 * <input type="button" name="decode" value="Decode from base64" 
	onClick="document.base64Form.theText.value=decode64(document.base64Form.theText.value);">
 */

var keyStr = "ABCDEFGHIJKLMNOP" +
                "QRSTUVWXYZabcdef" +
                "ghijklmnopqrstuv" +
                "wxyz0123456789+/" +
                "=";

function encode64(input) {
  input = escape(input);
  var output = "";
  var chr1, chr2, chr3 = "";
  var enc1, enc2, enc3, enc4 = "";
  var i = 0;

  do {
	 chr1 = input.charCodeAt(i++);
	 chr2 = input.charCodeAt(i++);
	 chr3 = input.charCodeAt(i++);

	 enc1 = chr1 >> 2;
	 enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
	 enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
	 enc4 = chr3 & 63;

	 if (isNaN(chr2)) {
		enc3 = enc4 = 64;
	 } else if (isNaN(chr3)) {
		enc4 = 64;
	 }

	 output = output + 
		keyStr.charAt(enc1) + 
		keyStr.charAt(enc2) + 
		keyStr.charAt(enc3) + 
		keyStr.charAt(enc4);
	 chr1 = chr2 = chr3 = "";
	 enc1 = enc2 = enc3 = enc4 = "";
  } while (i < input.length);

  return output;
}

function decode64(input) {
  var output = "";
  var chr1, chr2, chr3 = "";
  var enc1, enc2, enc3, enc4 = "";
  var i = 0;

  // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
  var base64test = /[^A-Za-z0-9\+\/\=]/g;
  if (base64test.exec(input)) {
	 alert("There were invalid base64 characters in the input text.\n" +
		   "Valid base64 characters are A-Z, a-z, 0-9, ''+'', ''/'', and ''=''\n" +
		   "Expect errors in decoding.");
  }
  input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

  do {
	 enc1 = keyStr.indexOf(input.charAt(i++));
	 enc2 = keyStr.indexOf(input.charAt(i++));
	 enc3 = keyStr.indexOf(input.charAt(i++));
	 enc4 = keyStr.indexOf(input.charAt(i++));

	 chr1 = (enc1 << 2) | (enc2 >> 4);
	 chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
	 chr3 = ((enc3 & 3) << 6) | enc4;

	 output = output + String.fromCharCode(chr1);

	 if (enc3 != 64) {
		output = output + String.fromCharCode(chr2);
	 }
	 if (enc4 != 64) {
		output = output + String.fromCharCode(chr3);
	 }

	 chr1 = chr2 = chr3 = "";
	 enc1 = enc2 = enc3 = enc4 = "";

  } while (i < input.length);

  return unescape(output);
}
//--end --