JavaScript SHA1加密算法实现详细代码详解编程语言

/* 
 * 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, Lostinet 
 * Distributed under the BSD License 
 * See http://pajhome.org.uk/crypt/md5 for details. 
 * http://www.sharejs.com 
 */ 
 
/* 
 * 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_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 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; 
} 
 
/* 
 * 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 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; 
} 
 
/* 
 * 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, cnt) 
{ 
  return (num << cnt) | (num >>> (32 - cnt)); 
} 
 

原创文章,作者:ItWorker,如若转载,请注明出处:https://blog.ytso.com/tech/pnotes/8859.html

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