• Configurable variables. You may need to tweak these to be compatible with
• the server-side,but the defaults work in most cases.
  /
  var hexcase = 0; / hex output format. 0 - lowercase; 1 - uppercase /
  var b64pad = ""; / base-64 pad character. "=" for strict RFC compliance */

/*

• These are the functions you'll usually want to call
• They take string arguments and return either hex or base-64 encoded strings
  */
  function hex_sha256(s) { return rstr2hex(rstr_sha256(str2rstr_utf8(s))); }
  function b64_sha256(s) { return rstr2b64(rstr_sha256(str2rstr_utf8(s))); }
  function any_sha256(s,e) { return rstr2any(rstr_sha256(str2rstr_utf8(s)),e); }
  function hex_hmac_sha256(k,d)
  { return rstr2hex(rstr_hmac_sha256(str2rstr_utf8(k),str2rstr_utf8(d))); }
  function b64_hmac_sha256(k,d)
  { return rstr2b64(rstr_hmac_sha256(str2rstr_utf8(k),str2rstr_utf8(d))); }
  function any_hmac_sha256(k,d,e)
  { return rstr2any(rstr_hmac_sha256(str2rstr_utf8(k),str2rstr_utf8(d)),e); }

/*

• Perform a simple self-test to see if the VM is working
  */
  function sha256_vm_test()
  {
  return hex_sha256("abc").toLowerCase() ==
  "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad";
  }

/*

• Calculate the sha256 of a raw string
  /
  function rstr_sha256(s)
  {
  return binb2rstr(binb_sha256(rstr2binb(s),s.length 8));
  }

/*

• Calculate the HMAC-sha256 of a key and some data (raw strings)
  /
  function rstr_hmac_sha256(key,data)
  {
  var bkey = rstr2binb(key);
  if(bkey.length > 16) bkey = binb_sha256(bkey,key.length 8);

var ipad = Array(16),opad = Array(16);
for(var i = 0; i < 16; i++)
{
ipad[i] = bkey[i] ^ 0x36363636;
opad[i] = bkey[i] ^ 0x5C5C5C5C;
}

var hash = binb_sha256(ipad.concat(rstr2binb(data)),512 + data.length * 8);
return binb2rstr(binb_sha256(opad.concat(hash),512 + 256));
}

/*

• Convert a raw string to a hex string
  */
  function rstr2hex(input)
  {
  try { hexcase } catch(e) { hexcase=0; }
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var output = "";
  var x;
  for(var i = 0; i < input.length; i++)
  {
  x = input.charCodeAt(i);
  output += hex_tab.charAt((x >>> 4) & 0x0F)
  • hex_tab.charAt( x & 0x0F);
    }
    return output;
    }

/*

• Convert a raw string to a base-64 string
  /
  function rstr2b64(input)
  {
  try { b64pad } catch(e) { b64pad=''; }
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var output = "";
  var len = input.length;
  for(var i = 0; i < len; i += 3)
  {
  var triplet = (input.charCodeAt(i) << 16)
  | (i + 1 < len ? input.charCodeAt(i+1) << 8 : 0)
  | (i + 2 < len ? input.charCodeAt(i+2) : 0);
  for(var j = 0; j < 4; j++)
  {
  if(i 8 + j 6 > input.length 8) output += b64pad;
  else output += tab.charAt((triplet >>> 6*(3-j)) & 0x3F);
  }
  }
  return output;
  }

/*

• Convert a raw string to an arbitrary string encoding
  */
  function rstr2any(input,encoding)
  {
  var divisor = encoding.length;
  var remainders = Array();
  var i,q,x,quotient;

/ Convert to an array of 16-bit big-endian values,forming the dividend /
var dividend = Array(Math.ceil(input.length / 2));
for(i = 0; i < dividend.length; i++)
{
dividend[i] = (input.charCodeAt(i 2) << 8) | input.charCodeAt(i 2 + 1);
}

/*

• Repeatedly perform a long division. The binary array forms the dividend,* the length of the encoding is the divisor. Once computed,the quotient
• forms the dividend for the next step. We stop when the dividend is zero.
• All remainders are stored for later use.
  /
  while(dividend.length > 0)
  {
  quotient = Array();
  x = 0;
  for(i = 0; i < dividend.length; i++)
  {
  x = (x << 16) + dividend[i];
  q = Math.floor(x / divisor);
  x -= q divisor;
  if(quotient.length > 0 || q > 0)
  quotient[quotient.length] = q;
  }
  remainders[remainders.length] = x;
  dividend = quotient;
  }

/ Convert the remainders to the output string /
var output = "";
for(i = remainders.length - 1; i >= 0; i--)
output += encoding.charAt(remainders[i]);

/ Append leading zero equivalents /
var full_length = Math.ceil(input.length * 8 /
(Math.log(encoding.length) / Math.log(2)))
for(i = output.length; i < full_length; i++)
output = encoding[0] + output;

return output;
}

/*

• Encode a string as utf-8.
• For efficiency,this assumes the input is valid utf-16.
  */
  function str2rstr_utf8(input)
  {
  var output = "";
  var i = -1;
  var x,y;

while(++i < input.length)
{
/ Decode utf-16 surrogate pairs /
x = input.charCodeAt(i);
y = i + 1 < input.length ? input.charCodeAt(i + 1) : 0;
if(0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF)
{
x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
i++;
}

/ Encode output as utf-8 /
if(x <= 0x7F)
output += String.fromCharCode(x);
else if(x <= 0x7FF)
output += String.fromCharCode(0xC0 | ((x >>> 6 ) & 0x1F),0x80 | ( x & 0x3F));
else if(x <= 0xFFFF)
output += String.fromCharCode(0xE0 | ((x >>> 12) & 0x0F),0x80 | ((x >>> 6 ) & 0x3F),0x80 | ( x & 0x3F));
else if(x <= 0x1FFFFF)
output += String.fromCharCode(0xF0 | ((x >>> 18) & 0x07),0x80 | ((x >>> 12) & 0x3F),0x80 | ( x & 0x3F));
}
return output;
}

/*

• Encode a string as utf-16
  */
  function str2rstr_utf16le(input)
  {
  var output = "";
  for(var i = 0; i < input.length; i++)
  output += String.fromCharCode( input.charCodeAt(i) & 0xFF,(input.charCodeAt(i) >>> 8) & 0xFF);
  return output;
  }

function str2rstr_utf16be(input)
{
var output = "";
for(var i = 0; i < input.length; i++)
output += String.fromCharCode((input.charCodeAt(i) >>> 8) & 0xFF,input.charCodeAt(i) & 0xFF);
return output;
}

/*

• Convert a raw string to an array of big-endian words
• Characters >255 have their high-byte silently ignored.
  /
  function rstr2binb(input)
  {
  var output = Array(input.length >> 2);
  for(var i = 0; i < output.length; i++)
  output[i] = 0;
  for(var i = 0; i < input.length 8; i += 8)
  output[i>>5] |= (input.charCodeAt(i / 8) & 0xFF) << (24 - i % 32);
  return output;
  }

/*

• Convert an array of big-endian words to a string
  /
  function binb2rstr(input)
  {
  var output = "";
  for(var i = 0; i < input.length 32; i += 8)
  output += String.fromCharCode((input[i>>5] >>> (24 - i % 32)) & 0xFF);
  return output;
  }

/*

• Main sha256 function,with its support functions
  */
  function sha256_S (X,n) {return ( X >>> n ) | (X << (32 - n));}
  function sha256_R (X,n) {return ( X >>> n );}
  function sha256_Ch(x,y,z) {return ((x & y) ^ ((~x) & z));}
  function sha256_Maj(x,z) {return ((x & y) ^ (x & z) ^ (y & z));}
  function sha256_Sigma0256(x) {return (sha256_S(x,2) ^ sha256_S(x,13) ^ sha256_S(x,22));}
  function sha256_Sigma1256(x) {return (sha256_S(x,6) ^ sha256_S(x,11) ^ sha256_S(x,25));}
  function sha256_Gamma0256(x) {return (sha256_S(x,7) ^ sha256_S(x,18) ^ sha256_R(x,3));}
  function sha256_Gamma1256(x) {return (sha256_S(x,17) ^ sha256_S(x,19) ^ sha256_R(x,10));}
  function sha256_Sigma0512(x) {return (sha256_S(x,28) ^ sha256_S(x,34) ^ sha256_S(x,39));}
  function sha256_Sigma1512(x) {return (sha256_S(x,14) ^ sha256_S(x,18) ^ sha256_S(x,41));}
  function sha256_Gamma0512(x) {return (sha256_S(x,1) ^ sha256_S(x,8) ^ sha256_R(x,7));}
  function sha256_Gamma1512(x) {return (sha256_S(x,19) ^ sha256_S(x,61) ^ sha256_R(x,6));}

var sha256_K = new Array
(
1116352408,1899447441,-1245643825,-373957723,961987163,1508970993,-1841331548,-1424204075,-670586216,310598401,607225278,1426881987,1925078388,-2132889090,-1680079193,-1046744716,-459576895,-272742522,264347078,604807628,770255983,1249150122,1555081692,1996064986,-1740746414,-1473132947,-1341970488,-1084653625,-958395405,-710438585,113926993,338241895,666307205,773529912,1294757372,1396182291,1695183700,1986661051,-2117940946,-1838011259,-1564481375,-1474664885,-1035236496,-949202525,-778901479,-694614492,-200395387,275423344,430227734,506948616,659060556,883997877,958139571,1322822218,1537002063,1747873779,1955562222,2024104815,-2067236844,-1933114872,-1866530822,-1538233109,-1090935817,-965641998
);

function binb_sha256(m,l)
{
var HASH = new Array(1779033703,-1150833019,1013904242,-1521486534,1359893119,-1694144372,528734635,1541459225);
var W = new Array(64);
var a,b,c,e,f,g,h;
var i,j,T1,T2;

/ append padding /
m[l >> 5] |= 0x80 << (24 - l % 32);
m[((l + 64 >> 9) << 4) + 15] = l;

for(i = 0; i < m.length; i += 16)
{
a = HASH[0];
b = HASH[1];
c = HASH[2];
d = HASH[3];
e = HASH[4];
f = HASH[5];
g = HASH[6];
h = HASH[7];

for(j = 0; j < 64; j++)
{
if (j < 16) W[j] = m[j + i];
else W[j] = safe_add(safe_add(safe_add(sha256_Gamma1256(W[j - 2]),W[j - 7]),sha256_Gamma0256(W[j - 15])),W[j - 16]);

T1 = safe_add(safe_add(safe_add(safe_add(h,sha256_Sigma1256(e)),sha256_Ch(e,g)),sha256_K[j]),W[j]);
T2 = safe_add(sha256_Sigma0256(a),sha256_Maj(a,c));
h = g;
g = f;
f = e;
e = safe_add(d,T1);
d = c;
c = b;
b = a;
a = safe_add(T1,T2);
}

HASH[0] = safe_add(a,HASH[0]);
HASH[1] = safe_add(b,HASH[1]);
HASH[2] = safe_add(c,HASH[2]);
HASH[3] = safe_add(d,HASH[3]);
HASH[4] = safe_add(e,HASH[4]);
HASH[5] = safe_add(f,HASH[5]);
HASH[6] = safe_add(g,HASH[6]);
HASH[7] = safe_add(h,HASH[7]);
}
return HASH;
}

function safe_add (x,y)
{
var lsw = (x & 0xFFFF) + (y & 0xFFFF);
var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
return (msw << 16) | (lsw & 0xFFFF);
}