JavaScript SHA-256加密算法詳細代碼

fdpg 9年前發布 | 3K 次閱讀 JavaScript
/*

A JavaScript implementation of the Secure Hash Algorithm, SHA-256, as defined
in FIPS 180-2
Version 2.2 Copyright Angel Marin, 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.
Also http://anmar.eu.org/projects/jssha2/
*/

/*

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_sha256(s)    { return rstr2hex(rstr_sha256(str2rstr_utf8(s))); }
function b64_sha256(s)    { return rstr2b64(rstr_sha256(str2rstr_utf8(s))); }
function any_sha256(s, e) { return rstr2any(rstr_sha256(str2rstr_utf8(s)), e); }
function hex_hmac_sha256(k, d)
{ return rstr2hex(rstr_hmac_sha256(str2rstr_utf8(k), str2rstr_utf8(d))); }
function b64_hmac_sha256(k, d)
{ return rstr2b64(rstr_hmac_sha256(str2rstr_utf8(k), str2rstr_utf8(d))); }
function any_hmac_sha256(k, d, e)
{ return rstr2any(rstr_hmac_sha256(str2rstr_utf8(k), str2rstr_utf8(d)), e); }

/*

Perform a simple self-test to see if the VM is working
*/
function sha256_vm_test()
{
return hex_sha256("abc").toLowerCase() ==
     "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad";

}

/*

Calculate the sha256 of a raw string
/
function rstr_sha256(s)
{
return binb2rstr(binb_sha256(rstr2binb(s), s.length  8));
}

/*

Calculate the HMAC-sha256 of a key and some data (raw strings)
/
function rstr_hmac_sha256(key, data)
{
var bkey = rstr2binb(key);
if(bkey.length > 16) bkey = binb_sha256(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_sha256(ipad.concat(rstr2binb(data)), 512 + data.length * 8);
return binb2rstr(binb_sha256(opad.concat(hash), 512 + 256));
}


/*

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 computed, the quotient
forms the dividend for the next step. We stop 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;
}

/*

Main sha256 function, with its support functions
*/
function sha256_S (X, n) {return ( X >>> n ) | (X << (32 - n));}
function sha256_R (X, n) {return ( X >>> n );}
function sha256_Ch(x, y, z) {return ((x & y) ^ ((~x) & z));}
function sha256_Maj(x, y, z) {return ((x & y) ^ (x & z) ^ (y & z));}
function sha256_Sigma0256(x) {return (sha256_S(x, 2) ^ sha256_S(x, 13) ^ sha256_S(x, 22));}
function sha256_Sigma1256(x) {return (sha256_S(x, 6) ^ sha256_S(x, 11) ^ sha256_S(x, 25));}
function sha256_Gamma0256(x) {return (sha256_S(x, 7) ^ sha256_S(x, 18) ^ sha256_R(x, 3));}
function sha256_Gamma1256(x) {return (sha256_S(x, 17) ^ sha256_S(x, 19) ^ sha256_R(x, 10));}
function sha256_Sigma0512(x) {return (sha256_S(x, 28) ^ sha256_S(x, 34) ^ sha256_S(x, 39));}
function sha256_Sigma1512(x) {return (sha256_S(x, 14) ^ sha256_S(x, 18) ^ sha256_S(x, 41));}
function sha256_Gamma0512(x) {return (sha256_S(x, 1)  ^ sha256_S(x, 8) ^ sha256_R(x, 7));}
function sha256_Gamma1512(x) {return (sha256_S(x, 19) ^ sha256_S(x, 61) ^ sha256_R(x, 6));}

var sha256_K = new Array
(
  1116352408, 1899447441, -1245643825, -373957723, 961987163, 1508970993,
  -1841331548, -1424204075, -670586216, 310598401, 607225278, 1426881987,
  1925078388, -2132889090, -1680079193, -1046744716, -459576895, -272742522,
  264347078, 604807628, 770255983, 1249150122, 1555081692, 1996064986,
  -1740746414, -1473132947, -1341970488, -1084653625, -958395405, -710438585,
  113926993, 338241895, 666307205, 773529912, 1294757372, 1396182291,
  1695183700, 1986661051, -2117940946, -1838011259, -1564481375, -1474664885,
  -1035236496, -949202525, -778901479, -694614492, -200395387, 275423344,
  430227734, 506948616, 659060556, 883997877, 958139571, 1322822218,
  1537002063, 1747873779, 1955562222, 2024104815, -2067236844, -1933114872,
  -1866530822, -1538233109, -1090935817, -965641998
);
function binb_sha256(m, l)
{
  var HASH = new Array(1779033703, -1150833019, 1013904242, -1521486534,
                       1359893119, -1694144372, 528734635, 1541459225);
  var W = new Array(64);
  var a, b, c, d, e, f, g, h;
  var i, j, T1, T2;
/ append padding /
  m[l >> 5] |= 0x80 << (24 - l % 32);
  m[((l + 64 >> 9) << 4) + 15] = l;
for(i = 0; i < m.length; i += 16)
  {
    a = HASH[0];
    b = HASH[1];
    c = HASH[2];
    d = HASH[3];
    e = HASH[4];
    f = HASH[5];
    g = HASH[6];
    h = HASH[7];

for(j = 0; j < 64; j++)
{
  if (j < 16) W[j] = m[j + i];
  else W[j] = safe_add(safe_add(safe_add(sha256_Gamma1256(W[j - 2]), W[j - 7]),
                                        sha256_Gamma0256(W[j - 15])), W[j - 16]);

  T1 = safe_add(safe_add(safe_add(safe_add(h, sha256_Sigma1256(e)), sha256_Ch(e, f, g)),
                                                      sha256_K[j]), W[j]);
  T2 = safe_add(sha256_Sigma0256(a), sha256_Maj(a, b, c));
  h = g;
  g = f;
  f = e;
  e = safe_add(d, T1);
  d = c;
  c = b;
  b = a;
  a = safe_add(T1, T2);
}

HASH[0] = safe_add(a, HASH[0]);
HASH[1] = safe_add(b, HASH[1]);
HASH[2] = safe_add(c, HASH[2]);
HASH[3] = safe_add(d, HASH[3]);
HASH[4] = safe_add(e, HASH[4]);
HASH[5] = safe_add(f, HASH[5]);
HASH[6] = safe_add(g, HASH[6]);
HASH[7] = safe_add(h, HASH[7]);

}
  return HASH;
}
function safe_add (x, y)
{
  var lsw = (x & 0xFFFF) + (y & 0xFFFF);
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xFFFF);
}
 </pre>
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