JavaScript SHA-256加密算法详细代码详解编程语言

/* 
 * 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); 
} 
 

原创文章,作者:ItWorker,如若转载,请注明出处:https://blog.ytso.com/tech/pnotes/8858.html

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