JavaScript SHA-256加密算法详细代码

/* * 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);}