/* A JavaScript implementation of the Secure Hash Standard
 * Version 0.3 Copyright Angel Marin 2003-2004 - http://anmar.eu.org/
 * Distributed under the BSD License
 * Some bits taken from Paul Johnston's SHA-1 implementation
 */
var chrsz   = 8;  /* bits per input character. 8 - ASCII; 16 - Unicode      */
var hexcase = 0;/* hex output format. 0 - lowercase; 1 - uppercase        */

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

function S (X, n) {return ( X >>> n ) | (X << (32 - n));}

function R (X, n) {return ( X >>> n );}

function Ch(x, y, z) {return ((x & y) ^ ((~x) & z));}

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

function Sigma0256(x) {return (S(x, 2) ^ S(x, 13) ^ S(x, 22));}

function Sigma1256(x) {return (S(x, 6) ^ S(x, 11) ^ S(x, 25));}

function Gamma0256(x) {return (S(x, 7) ^ S(x, 18) ^ R(x, 3));}

function Gamma1256(x) {return (S(x, 17) ^ S(x, 19) ^ R(x, 10));}

function Sigma0512(x) {return (S(x, 28) ^ S(x, 34) ^ S(x, 39));}

function Sigma1512(x) {return (S(x, 14) ^ S(x, 18) ^ S(x, 41));}

function Gamma0512(x) {return (S(x, 1) ^ S(x, 8) ^ R(x, 7));}

function Gamma1512(x) {return (S(x, 19) ^ S(x, 61) ^ R(x, 6));}

function core_sha256 (m, l) {
    var K = new Array(0x428A2F98,0x71374491,0xB5C0FBCF,0xE9B5DBA5,0x3956C25B,0x59F111F1,0x923F82A4,0xAB1C5ED5,0xD807AA98,0x12835B01,0x243185BE,0x550C7DC3,0x72BE5D74,0x80DEB1FE,0x9BDC06A7,0xC19BF174,0xE49B69C1,0xEFBE4786,0xFC19DC6,0x240CA1CC,0x2DE92C6F,0x4A7484AA,0x5CB0A9DC,0x76F988DA,0x983E5152,0xA831C66D,0xB00327C8,0xBF597FC7,0xC6E00BF3,0xD5A79147,0x6CA6351,0x14292967,0x27B70A85,0x2E1B2138,0x4D2C6DFC,0x53380D13,0x650A7354,0x766A0ABB,0x81C2C92E,0x92722C85,0xA2BFE8A1,0xA81A664B,0xC24B8B70,0xC76C51A3,0xD192E819,0xD6990624,0xF40E3585,0x106AA070,0x19A4C116,0x1E376C08,0x2748774C,0x34B0BCB5,0x391C0CB3,0x4ED8AA4A,0x5B9CCA4F,0x682E6FF3,0x748F82EE,0x78A5636F,0x84C87814,0x8CC70208,0x90BEFFFA,0xA4506CEB,0xBEF9A3F7,0xC67178F2);
    var HASH = new Array(0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19);
    var W = new Array(64);
    var a, b, c, d, e, f, g, h, i, j;
    var T1, T2;

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

    for ( var 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 ( var j = 0; j<64; j++) {
            if (j < 16) W[j] = m[j + i];
            else W[j] = safe_add(safe_add(safe_add(Gamma1256(W[j - 2]), W[j - 7]), Gamma0256(W[j - 15])), W[j - 16]);

            T1 = safe_add(safe_add(safe_add(safe_add(h, Sigma1256(e)), Ch(e, f, g)), K[j]), W[j]);
            T2 = safe_add(Sigma0256(a), Maj(a, b, 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 str2binb (str) {
  var bin = Array();
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < str.length * chrsz; i += chrsz)
    bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (24 - i%32);
  return bin;
}

function binb2str (bin) {
  var str = "";
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < bin.length * 32; i += chrsz)
    str += String.fromCharCode((bin[i>>5] >>> (24 - i%32)) & mask);
  return str;
}

function binb2hex (binarray) {
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var str = "";
  for(var i = 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;
}

function binb2b64 (binarray) {
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i += 3)
  {
    var triplet = (((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 = 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;
}

function hex_sha256(s){return binb2hex(core_sha256(str2binb(s),s.length * chrsz));}
function b64_sha256(s){return binb2b64(core_sha256(str2binb(s),s.length * chrsz));}
function str_sha256(s){return binb2str(core_sha256(str2binb(s),s.length * chrsz));}