Javascript SHA-1：Secure Hash Algorithm

From:http://pajhome.org.uk/crypt/md5/sha1src.html

/*

 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined

 * in FIPS PUB 180-1

 * Version 2.1a Copyright Paul Johnston 2000 - 2002.

 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet

 * Distributed under the BSD License

 * See http://pajhome.org.uk/crypt/md5 for details.

 */

/*

 * 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  */

var chrsz  = 8; /* bits per input character. 8 - ASCII; 16 - Unicode   */
/*

 * 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 binb2hex(core_sha1(str2binb(s),s.length * chrsz));}

function b64_sha1(s){return binb2b64(core_sha1(str2binb(s),s.length * chrsz));}

function str_sha1(s){return binb2str(core_sha1(str2binb(s),s.length * chrsz));}

function hex_hmac_sha1(key, data){ return binb2hex(core_hmac_sha1(key, data));}

function b64_hmac_sha1(key, data){ return binb2b64(core_hmac_sha1(key, data));}

function str_hmac_sha1(key, data){ return binb2str(core_hmac_sha1(key, data));}
/*

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

 */

function sha1_vm_test()

{

 return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";

}
/*

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

 */

function core_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] = 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

 */

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;

}
/*

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

 */

function core_hmac_sha1(key, data)

{

 var bkey = str2binb(key);

 if(bkey.length > 16) bkey = core_sha1(bkey, key.length * chrsz);
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 = 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.

 */

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 rol(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.

 */

function str2binb(str)

{

 var bin = Array();

 var mask = (1 << chrsz) - 1;

 for(var 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

 */

function binb2str(bin)

{

 var str = "";

 var mask = (1 << chrsz) - 1;

 for(var 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.

 */

function binb2hex(binarray)

{

 var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";

 var str = "";

 for(var 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;

}
/*

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

 */

function binb2b64(binarray)

{

 var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

 var str = "";

 for(var 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(var j = 0; j < 4; j++)

  {

   if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;

   else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);

  }

 }

 return str;

}