JavaScript SHA1加密算法实现详细代码

/*
 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined
 * in FIPS 180-1
 * Version 2.2 Copyright Paul Johnston 2000 - 2009.
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for details.
 * http://www.sharejs.com
 */
 
/*
 * 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_sha1(s)  { return rstr2hex(rstr_sha1(str2rstr_utf8(s))); }
function b64_sha1(s)  { return rstr2b64(rstr_sha1(str2rstr_utf8(s))); }
function any_sha1(s, e) { return rstr2any(rstr_sha1(str2rstr_utf8(s)), e); }
function hex_hmac_sha1(k, d)
 { return rstr2hex(rstr_hmac_sha1(str2rstr_utf8(k), str2rstr_utf8(d))); }
function b64_hmac_sha1(k, d)
 { return rstr2b64(rstr_hmac_sha1(str2rstr_utf8(k), str2rstr_utf8(d))); }
function any_hmac_sha1(k, d, e)
 { return rstr2any(rstr_hmac_sha1(str2rstr_utf8(k), str2rstr_utf8(d)), e); }
 
/*
 * Perform a simple self-test to see if the VM is working
 */
function sha1_vm_test()
{
 return hex_sha1("abc").toLowerCase() == "a9993e364706816aba3e25717850c26c9cd0d89d";
}
 
/*
 * Calculate the SHA1 of a raw string
 */
function rstr_sha1(s)
{
 return binb2rstr(binb_sha1(rstr2binb(s), s.length * 8));
}
 
/*
 * Calculate the HMAC-SHA1 of a key and some data (raw strings)
 */
function rstr_hmac_sha1(key, data)
{
 var bkey = rstr2binb(key);
 if(bkey.length > 16) bkey = binb_sha1(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_sha1(ipad.concat(rstr2binb(data)), 512 + data.length * 8);
 return binb2rstr(binb_sha1(opad.concat(hash), 512 + 160));
}
 
/*
 * 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 "";
 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 "";
 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[i5] |= (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[i5] > (24 - i % 32)) & 0xFF);
 return output;
}
 
/*
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 */
function binb_sha1(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;
 
 for(var i = 0; i < x.length; i += 16)
 {
  var olda = a;
  var oldb = b;
  var oldc = c;
  var oldd = d;
  var olde = e;
 
  for(var j = 0; j < 80; j++)
  {
   if(j < 16) w[j] = x[i + j];
   else w[j] = bit_rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
   var t = safe_add(safe_add(bit_rol(a, 5), sha1_ft(j, b, c, d)),
            safe_add(safe_add(e, w[j]), sha1_kt(j)));
   e = d;
   d = c;
   c = bit_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
 */
function sha1_ft(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
 */
function sha1_kt(t)
{
 return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 :
     (t < 60) ? -1894007588 : -899497514;
}
 
/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
function safe_add(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.
 */
function bit_rol(num, cnt)
{
 return (num << cnt) | (num > (32 - cnt));
}