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, Losti
  Distributed under the BSD License
  See http://pajhome..uk/crypt/md5 for details.
  http://.sharejs.
 /
 
/
  Configurable variables. You may need to tweak these to be patible 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 pliance  /
 
/
  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 ? input.charCodeAt(i+1) << 8 : 0)
        | (i + 2 < len ? input.charCodeAt(i+2)   : 0);
  for(var j = 0; j < 4; j++)
  {
   if(i  8 + j  6 > input.length  8) output += b64pad;
   else output += tab.charAt((triplet >>> 6(3-j)) & 0x3F);
  }
 }
 return output;
}
 
/
  Convert a raw string to an arbitrary string encoding
 /
function rstr2any(input, encoding)
{
 var divisor = encoding.length;
 var remainders = Array();
 var i, q, x, quotient;
 
 / Convert to an array of 16-bit big-endian values, forming the dividend /
 var dividend = Array(Math.ceil(input.length / 2));
 for(i = 0; i < dividend.length; i++)
 {
  dividend[i] = (input.charCodeAt(i  2) << 8) | input.charCodeAt(i  2 + 1);
 }
 
 /
   Repeatedly perform a long division. The binary array forms the dividend,
   the length of the encoding is the divisor. Once puted, the quotient
   forms the dividend for the next step. We s when the dividend is zero.
   All remainders are stored for later use.
  /
 while(dividend.length > 0)
 {
  quotient = Array();
  x = 0;
  for(i = 0; i < dividend.length; i++)
  {
   x = (x << 16) + dividend[i];
   q = Math.floor(x / divisor);
   x -= q  divisor;
   if(quotient.length > 0 || q > 0)
    quotient[quotient.length] = q;
  }
  remainders[remainders.length] = x;
  dividend = quotient;
 }
 
 / Convert the remainders to the output string /
 var output = "";
 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 ? input.charCodeAt(i + 1) : 0;
  if(0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF)
  {
   x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
   i++;
  }
 
  / Encode output as utf-8 /
  if(x <= 0x7F)
   output += String.fromCharCode(x);
  else if(x <= 0x7FF)
   output += String.fromCharCode(0xC0 | ((x >>> 6 ) & 0x1F),
                  0x80 | ( x     & 0x3F));
  else if(x <= 0xFFFF)
   output += String.fromCharCode(0xE0 | ((x >>> 12) & 0x0F),
                  0x80 | ((x >>> 6 ) & 0x3F),
                  0x80 | ( x     & 0x3F));
  else if(x <= 0x1FFFFF)
   output += String.fromCharCode(0xF0 | ((x >>> 18) & 0x07),
                  0x80 | ((x >>> 12) & 0x3F),
                  0x80 | ((x >>> 6 ) & 0x3F),
                  0x80 | ( x     & 0x3F));
 }
 return output;
}
 
/
  Encode a string as utf-16
 /
function str2rstr_utf16le(input)
{
 var output = "";
 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[i>>5] |= (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[i>>5] >>> (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 bination 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, t)
{
 return (num << t) | (num >>> (32 - t));
}