Secure Hash Algorithm (SHA256)

sha256.js

/**
*
*  Secure Hash Algorithm (SHA256)
*  http://www.webtoolkit.info/
*
*  Original code by Angel Marin, Paul Johnston.
*
**/

function SHA256(s){
  let chrsz   = 8;
  let hexcase = 0;

  function safe_add(x, y) {
    let lsw = (x & 0xFFFF) + (y & 0xFFFF);
    let 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 core_sha256(m, l) {
    let 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);
    let HASH = new Array(0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19);
    let W = new Array(64);
    let a, b, c, d, e, f, g, h, i, j;
    let T1, T2;

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

    for (let 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 (let 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) {
    let bin = Array();
    let mask = (1 << chrsz) - 1;

    for(let i = 0; i < str.length * chrsz; i += chrsz) {
      bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (24 - i % 32);
    }

    return bin;
  }

  function Utf8Encode(string) {
    string = string.replace(/\r\n/g, "\n");
    
    let utftext = "";

    for (let n = 0; n < string.length; n++) {
      let c = string.charCodeAt(n);

      if (c < 128) {
        utftext += String.fromCharCode(c);
      }
      else if ((c > 127) && (c < 2048)) {
        utftext += String.fromCharCode((c >> 6) | 192);
        utftext += String.fromCharCode((c & 63) | 128);
      }
      else {
        utftext += String.fromCharCode((c >> 12) | 224);
        utftext += String.fromCharCode(((c >> 6) & 63) | 128);
        utftext += String.fromCharCode((c & 63) | 128);
      }
    }

    return utftext;
  }

  function binb2hex(binarray) {
    let hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
    let str = "";

    for (let 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;
  }

  s = Utf8Encode(s);

  return binb2hex(core_sha256(str2binb(s), s.length * chrsz));
}