/* MD5 Message-Digest Algorithm - JavaScript
' MODIFICATION HISTORY:
' 1.0    16-Feb-2001 - Phil Fresle (sales@frez.co.uk) - Initial Version (VB/ASP code)
' 1.0    21-Feb-2001 - Enrico Mosanghini (erik504@yahoo.com) - JavaScript porting
*/
function chgstring(sMessage) {
   function RotateLeft(lValue, iShiftBits) {
      return (lValue<<iShiftBits) | (lValue>>>(32-iShiftBits));
   }

   function AddUnsigned(lX,lY) {
      var lX4,lY4,lX8,lY8,lResult;

      lX8 = (lX & 0x80000000);
      lY8 = (lY & 0x80000000);
      lX4 = (lX & 0x40000000);
      lY4 = (lY & 0x40000000);
      lResult = (lX & 0x3FFFFFFF)+(lY & 0x3FFFFFFF);

      if (lX4 & lY4) return (lResult ^ 0x80000000 ^ lX8 ^ lY8);
      if (lX4 | lY4) {
         if (lResult & 0x40000000)
            return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);
         else
            return (lResult ^ 0x40000000 ^ lX8 ^ lY8);
      }
      else
         return (lResult ^ lX8 ^ lY8);
   }

   function F(x,y,z) {
      return (x & y) | ((~x) & z);
   }

   function G(x,y,z) {
      return (x & z) | (y & (~z));
   }

   function H(x,y,z) {
      return (x ^ y ^ z);
   }

   function I(x,y,z) {
      return (y ^ (x | (~z)));
   }

   function FF(a,b,c,d,x,s,ac) {
      a = AddUnsigned(a, AddUnsigned(AddUnsigned(F(b, c, d), x), ac));
      return AddUnsigned(RotateLeft(a, s), b);
   }

   function GG(a,b,c,d,x,s,ac) {
      a = AddUnsigned(a, AddUnsigned(AddUnsigned(G(b, c, d), x), ac));
      return AddUnsigned(RotateLeft(a, s), b);
   }

   function HH(a,b,c,d,x,s,ac) {
      a = AddUnsigned(a, AddUnsigned(AddUnsigned(H(b, c, d), x), ac));
      return AddUnsigned(RotateLeft(a, s), b);
   }

   function II(a,b,c,d,x,s,ac) {
      a = AddUnsigned(a, AddUnsigned(AddUnsigned(I(b, c, d), x), ac));
      return AddUnsigned(RotateLeft(a, s), b);
   }

   function ConvertToWordArray(sMessage) {
      var lWordCount;
      var lMessageLength = sMessage.length;
      var lNumberOfWords_temp1=lMessageLength + 8;
      var lNumberOfWords_temp2=(lNumberOfWords_temp1-(lNumberOfWords_temp1 % 64))/64;
      var lNumberOfWords = (lNumberOfWords_temp2+1)*16;
      var lWordArray = Array(lNumberOfWords-1);
      var lBytePosition = 0;
      var lByteCount = 0;

      while ( lByteCount < lMessageLength ) {
         lWordCount = (lByteCount-(lByteCount % 4))/4;
         lBytePosition = (lByteCount % 4)*8;
         lWordArray[lWordCount] = (lWordArray[lWordCount] | (sMessage.charCodeAt(lByteCount)<<lBytePosition));
         lByteCount++;
      }

      lWordCount = (lByteCount-(lByteCount % 4))/4;
      lBytePosition = (lByteCount % 4)*8;
      lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80<<lBytePosition);
      lWordArray[lNumberOfWords-2] = lMessageLength<<3;
      lWordArray[lNumberOfWords-1] = lMessageLength>>>29;
      return lWordArray;
   }

   function WordToHex(lValue) {
      var WordToHexValue="",WordToHexValue_temp="",lByte,lCount;

      for (lCount=0; lCount<=3; lCount++) {
         lByte = (lValue>>>(lCount*8)) & 255;
         WordToHexValue_temp = "0" + lByte.toString(16);
         WordToHexValue = WordToHexValue + WordToHexValue_temp.substr(WordToHexValue_temp.length-2,2);
      }

      return WordToHexValue;
   }

   var x = Array();
   var k,AA,BB,CC,DD,a,b,c,d;
   var S11=7, S12=12, S13=17, S14=22;
   var S21=5, S22=9 , S23=14, S24=20;
   var S31=4, S32=11, S33=16, S34=23;
   var S41=6, S42=10, S43=15, S44=21;

   // Steps 1 and 2.  Append padding bits and length and convert to words
   x = ConvertToWordArray(sMessage);
   // Step 3.  Initialise
   a = 0x67452301; b = 0xEFCDAB89; c = 0x98BADCFE; d = 0x10325476;
   // Step 4.  Process the message in 16-word blocks
   for (k=0;k<x.length;k+=16) {
      AA=a; BB=b; CC=c; DD=d;
      a = FF(a,b,c,d,x[k+0], S11,0xD76AA478);
      d = FF(d,a,b,c,x[k+1], S12,0xE8C7B756);
      c = FF(c,d,a,b,x[k+2], S13,0x242070DB);
      b = FF(b,c,d,a,x[k+3], S14,0xC1BDCEEE);
      a = FF(a,b,c,d,x[k+4], S11,0xF57C0FAF);
      d = FF(d,a,b,c,x[k+5], S12,0x4787C62A);
      c = FF(c,d,a,b,x[k+6], S13,0xA8304613);
      b = FF(b,c,d,a,x[k+7], S14,0xFD469501);
      a = FF(a,b,c,d,x[k+8], S11,0x698098D8);
      d = FF(d,a,b,c,x[k+9], S12,0x8B44F7AF);
      c = FF(c,d,a,b,x[k+10],S13,0xFFFF5BB1);
      b = FF(b,c,d,a,x[k+11],S14,0x895CD7BE);
      a = FF(a,b,c,d,x[k+12],S11,0x6B901122);
      d = FF(d,a,b,c,x[k+13],S12,0xFD987193);
      c = FF(c,d,a,b,x[k+14],S13,0xA679438E);
      b = FF(b,c,d,a,x[k+15],S14,0x49B40821);
      a = GG(a,b,c,d,x[k+1], S21,0xF61E2562);
      d = GG(d,a,b,c,x[k+6], S22,0xC040B340);
      c = GG(c,d,a,b,x[k+11],S23,0x265E5A51);
      b = GG(b,c,d,a,x[k+0], S24,0xE9B6C7AA);
      a = GG(a,b,c,d,x[k+5], S21,0xD62F105D);
      d = GG(d,a,b,c,x[k+10],S22,0x2441453);
      c = GG(c,d,a,b,x[k+15],S23,0xD8A1E681);
      b = GG(b,c,d,a,x[k+4], S24,0xE7D3FBC8);
      a = GG(a,b,c,d,x[k+9], S21,0x21E1CDE6);
      d = GG(d,a,b,c,x[k+14],S22,0xC33707D6);
      c = GG(c,d,a,b,x[k+3], S23,0xF4D50D87);
      b = GG(b,c,d,a,x[k+8], S24,0x455A14ED);
      a = GG(a,b,c,d,x[k+13],S21,0xA9E3E905);
      d = GG(d,a,b,c,x[k+2], S22,0xFCEFA3F8);
      c = GG(c,d,a,b,x[k+7], S23,0x676F02D9);
      b = GG(b,c,d,a,x[k+12],S24,0x8D2A4C8A);
      a = HH(a,b,c,d,x[k+5], S31,0xFFFA3942);
      d = HH(d,a,b,c,x[k+8], S32,0x8771F681);
      c = HH(c,d,a,b,x[k+11],S33,0x6D9D6122);
      b = HH(b,c,d,a,x[k+14],S34,0xFDE5380C);
      a = HH(a,b,c,d,x[k+1], S31,0xA4BEEA44);
      d = HH(d,a,b,c,x[k+4], S32,0x4BDECFA9);
      c = HH(c,d,a,b,x[k+7], S33,0xF6BB4B60);
      b = HH(b,c,d,a,x[k+10],S34,0xBEBFBC70);
      a = HH(a,b,c,d,x[k+13],S31,0x289B7EC6);
      d = HH(d,a,b,c,x[k+0], S32,0xEAA127FA);
      c = HH(c,d,a,b,x[k+3], S33,0xD4EF3085);
      b = HH(b,c,d,a,x[k+6], S34,0x4881D05);
      a = HH(a,b,c,d,x[k+9], S31,0xD9D4D039);
      d = HH(d,a,b,c,x[k+12],S32,0xE6DB99E5);
      c = HH(c,d,a,b,x[k+15],S33,0x1FA27CF8);
      b = HH(b,c,d,a,x[k+2], S34,0xC4AC5665);
      a = II(a,b,c,d,x[k+0], S41,0xF4292244);
      d = II(d,a,b,c,x[k+7], S42,0x432AFF97);
      c = II(c,d,a,b,x[k+14],S43,0xAB9423A7);
      b = II(b,c,d,a,x[k+5], S44,0xFC93A039);
      a = II(a,b,c,d,x[k+12],S41,0x655B59C3);
      d = II(d,a,b,c,x[k+3], S42,0x8F0CCC92);
      c = II(c,d,a,b,x[k+10],S43,0xFFEFF47D);
      b = II(b,c,d,a,x[k+1], S44,0x85845DD1);
      a = II(a,b,c,d,x[k+8], S41,0x6FA87E4F);
      d = II(d,a,b,c,x[k+15],S42,0xFE2CE6E0);
      c = II(c,d,a,b,x[k+6], S43,0xA3014314);
      b = II(b,c,d,a,x[k+13],S44,0x4E0811A1);
      a = II(a,b,c,d,x[k+4], S41,0xF7537E82);
      d = II(d,a,b,c,x[k+11],S42,0xBD3AF235);
      c = II(c,d,a,b,x[k+2], S43,0x2AD7D2BB);
      b = II(b,c,d,a,x[k+9], S44,0xEB86D391);
      a = AddUnsigned(a,AA); b=AddUnsigned(b,BB); c=AddUnsigned(c,CC); d=AddUnsigned(d,DD);
   }
   // Step 5.  Output the 128 bit digest
   var temp = WordToHex(a) + WordToHex(b) + WordToHex(c) + WordToHex(d);
   return temp.toLowerCase();
}