index.js

/**
 * component-sha1
 */

/**
 * Configurable variables
 */

var hexcase = 0;   /* hex output format. 0 - lowercase; 1 - uppercase        */
var b64pad  = "="; /* base-64 pad character. "=" for strict RFC compliance   */
var chrsz   = 8;   /* bits per input character. 8 - ASCII; 16 - Unicode      */

/**
 * Perform a simple self-test to see if the VM is working
 */

var sha1_vm_test = function() {
  return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";
};

/**
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 */

var core_sha1 = function(x, len) {
  /* append padding */
  x[len >> 5] |= 0x80 << (24 - len % 32);
  x[((len + 64 >> 9) << 4) + 15] = len;

  var w = Array(80);
  var a =  1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d =  271733878;
  var e = -1009589776;

  var i;
  var j;

  for(i = 0; i < x.length; i += 16) {
    var olda = a;
    var oldb = b;
    var oldc = c;
    var oldd = d;
    var olde = e;

    for(j = 0; j < 80; j += 1) {
      if(j < 16) {
        w[j] = x[i + j];
      } else {
        w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
      }

      var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)), safe_add(safe_add(e, w[j]), sha1_kt(j)));
      e = d;
      d = c;
      c = rol(b, 30);
      b = a;
      a = t;
    }

    a = safe_add(a, olda);
    b = safe_add(b, oldb);
    c = safe_add(c, oldc);
    d = safe_add(d, oldd);
    e = safe_add(e, olde);
  }

  return Array(a, b, c, d, e);
};

/**
 * Perform the appropriate triplet combination function
 * for the current iteration
 */

var sha1_ft = function(t, b, c, d) {
  if(t < 20) return (b & c) | ((~b) & d);
  if(t < 40) return b ^ c ^ d;
  if(t < 60) return (b & c) | (b & d) | (c & d);

  return b ^ c ^ d;
};

/**
 * Determine the appropriate additive constant for the current iteration
 */

var sha1_kt = function(t) {
  return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 :
         (t < 60) ? -1894007588 : -899497514;
};

/**
 * Calculate the HMAC-SHA1 of a key and some data
 */

var core_hmac_sha1 = function(key, data) {
  var bkey = str2binb(key);
  if (bkey.length > 16) {
    bkey = core_sha1(bkey, key.length * chrsz);
  }
  var ipad = Array(16);
  var opad = Array(16);
  var i;

  for (i = 0; i < 16; i += 1) {
    ipad[i] = bkey[i] ^ 0x36363636;
    opad[i] = bkey[i] ^ 0x5C5C5C5C;
  }

  var hash = core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);

  return core_sha1(opad.concat(hash), 512 + 160);
};

/**
 * Add integers, wrapping at 2^32.
 * This uses 16-bit operations internally to work around bugs in some JS interpreters.
 */

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

  return (msw << 16) | (lsw & 0xFFFF);
};

/**
 * Bitwise rotate a 32-bit number to the left.
 */

var rol = function(num, cnt){
  return (num << cnt) | (num >>> (32 - cnt));
};

/**
 * Convert an 8-bit or 16-bit string to an array of big-endian words
 * In 8-bit function, characters >255 have their hi-byte silently ignored.
 */

var str2binb = function(str) {
  var bin = [];
  var mask = (1 << chrsz) - 1;
  var i;

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

  return bin;
};

/**
 * Convert an array of big-endian words to a string
 */

var binb2str = function(bin) {
  var str = "";
  var mask = (1 << chrsz) - 1;
  var i;

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

  return str;
};

/*
 * Convert an array of big-endian words to a hex string.
 */
var binb2hex = function(binarray) {
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var str = "";
  var i;

  for(i = 0; i < binarray.length * 4; i += 1) {
    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;
};

/**
 * Convert an array of big-endian words to a base-64 string
 */

var binb2b64 = function(binarray) {
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";
  var i;
  var j;

  for(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(j = 0; j < 4; j += 1) {
      if (i * 8 + j * 6 > binarray.length * 32) {
        str += b64pad;
      } else {
        str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);
      }
    }
  }

  return str;
};


/**
 * hex
 * Hashes a string using SHA1 and returns a hex representation of it.
 *
 * @param {String} s
 * @returns {String}
 * @api public
 */

exports.hex = function(s) {
  return binb2hex(core_sha1(str2binb(s), s.length * chrsz));
};

/**
 * base64
 * Hashes a string using SHA1 and returns a base64 representation of it.
 *
 * @param {String} s
 * @returns {String}
 * @api public
 */

exports.base64 = function(s) {
  return binb2b64(core_sha1(str2binb(s),s.length * chrsz));
};

/**
 * str
 * Hashes a string using SHA1 and returns a string representation of it.
 *
 * @param {String} s
 * @returns {String}
 * @api public
 */

exports.str = function(s) {
  return binb2str(core_sha1(str2binb(s),s.length * chrsz));
};

/**
 * hex_hmac
 * Calculates the HMAC-SHA1 of a key and some data,
 * returning a hex representation of it.
 *
 * @param {String} key
 * @param {String} data
 * @returns {String}
 * @api public
 */

exports.hex_hmac = function(key, data) {
  return binb2hex(core_hmac_sha1(key, data));
};

/**
 * base64_hmac
 * Calculates the HMAC-SHA1 of a key and some data,
 * returning a base64 representation of it.
 *
 * @param {String} key
 * @param {String} data
 * @returns {String}
 * @api public
 */

exports.base64_hmac = function(key, data) {
  return binb2b64(core_hmac_sha1(key, data));
};

/**
 * str_hmac
 * Calculates the HMAC-SHA1 of a key and some data,
 * returning a string representation of it.
 *
 * @param {String} key
 * @param {String} data
 * @returns {String}
 * @api public
 */

exports.str_hmac = function(key, data) {
  return binb2str(core_hmac_sha1(key, data));
};