gistfile1.js

exports.SHA1 = function() {
  this.H0 = 0x67452301;
  this.H1 = 0xEFCDAB89;
  this.H2 = 0x98BADCFE;
  this.H3 = 0x10325476;
  this.H4 = 0xC3D2E1F0;
  this.buffer = "";
  this.message_length = 0;
}

SHA1 = exports.SHA1;

SHA1.prototype.update = function(data) {
  this.buffer += data;
  this.message_length += data.length;
  if(this.buffer.length >= 64) {
    this.processBlock();
  }   
}

SHA1.prototype.finish = function() {
  // Pad buffer
  this.buffer += String.fromCharCode(0x80);

  if(this.buffer.length <= 56) {
    padding = 56 - this.buffer.length;
  } else {
    padding = 56 + (64-this.buffer.length);
  }

  for(i = 0;i < padding;i++) {
    this.buffer += String.fromCharCode(0x00);
  }
  
  // Append Message Length
  second = (this.message_length*8) & 0xffffffff;
  first  = Math.floor(((this.message_length*8)>>32)/Math.pow(2,32)) & 0xffffffff;

  this.buffer += this.int_to_string(first);
  this.buffer += this.int_to_string(second);

  this.processBlock();
  return this.H0.toHexStr() + this.H1.toHexStr() + this.H2.toHexStr() + this.H3.toHexStr() + this.H4.toHexStr();
}


SHA1.prototype.int_to_string = function(i) {
  s = ""
  s += String.fromCharCode((i >> 24) & 0xff);
  s += String.fromCharCode((i >> 16) & 0xff);
  s += String.fromCharCode((i >> 8) & 0xff);
  s += String.fromCharCode((i >> 0) & 0xff);
  return s;
}

SHA1.prototype.processBlock = function() {
  w = this.buffer_to_words();

  // Remove this block from buffer
  this.buffer = this.buffer.substr(64);

  var a = this.H0,
      b = this.H1,
      c = this.H2,
      d = this.H3,
      e = this.H4;

  for(i = 0;i < 80;i++) {
    if(i < 20) {
      f = (b & c) | ((~b) & d);
      k = 0x5A827999;
    } else if (i < 40) {
      f = b ^ c ^ d;
      k = 0x6ED9EBA1;
    } else if (i < 60) {
      f = (b & c) | (b & d) | (c & d);
      k = 0x8F1BBCDC;
    } else if (i < 80) {
      f = b ^ c ^ d;
      k = 0xCA62C1D6;
    }

    temp = (this.rotate_left(a, 5) + f + e + k + w[i]) & 0xffffffff;
    e = d;
    d = c;
    c = this.rotate_left(b, 30);
    b = a;
    a = temp;
  }
  this.H0 = (this.H0 + a) & 0xffffffff;
  this.H1 = (this.H1 + b) & 0xffffffff;
  this.H2 = (this.H2 + c) & 0xffffffff;
  this.H3 = (this.H3 + d) & 0xffffffff;
  this.H4 = (this.H4 + e) & 0xffffffff;
  if(this.buffer.length >= 64) {
    this.processBlock();
  }
}

SHA1.prototype.buffer_to_words = function() {
  words = new Array(80);
  for(i = 0;i < 16;i++) {
    n = 0;
    for(j = 0;j < 4;j++) {
      n = n + (this.buffer.charCodeAt(i*4+j) << ((3-j)*8));
    }
    words[i] = n;
  }
  return this.expand_words(words);
}

SHA1.prototype.expand_words = function(w) {
  for(i = 16;i < 80;i++) {
    w[i] = this.rotate_left((w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16]),1);
  }
  return w;
}

SHA1.prototype.rotate_left = function(n,s) {
  var t4 = ( n<<s ) | (n>>>(32-s));
  return t4;
};

Number.prototype.toHexStr = function()
{
  var s="", v;
  for (var i=7; i>=0; i--) { v = (this>>>(i*4)) & 0xf; s += v.toString(16); }
  return s;
}