微信小程序 MD5的方法详解及实例代码

/*

 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message

 * Digest Algorithm, as defined in RFC 1321.

 * Version 1.1 Copyright (C) Paul Johnston 1999 - 2002.

 * Code also contributed by Greg Holt

 * See http://pajhome.org.uk/site/legal.html for details.

 */ 

/*

 * Add integers, wrapping at 2^32. This uses 16-bit operations internally

 * to work around bugs in some JS interpreters.

 */ 

functionsafe_add(x, y) 

{ 

 varlsw = (x & 0xFFFF) + (y & 0xFFFF) 

 varmsw = (x >> 16) + (y >> 16) + (lsw >> 16) 

 return(msw << 16) | (lsw & 0xFFFF) 

} 

/*

 * Bitwise rotate a 32-bit number to the left.

 */ 

functionrol(num, cnt) 

{ 

 return(num << cnt) | (num >>> (32 - cnt)) 

} 

/*

 * These functions implement the four basic operations the algorithm uses.

 */ 

functioncmn(q, a, b, x, s, t) 

{ 

 returnsafe_add(rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b) 

} 

functionff(a, b, c, d, x, s, t) 

{ 

 returncmn((b & c) | ((~b) & d), a, b, x, s, t) 

} 

functiongg(a, b, c, d, x, s, t) 

{ 

 returncmn((b & d) | (c & (~d)), a, b, x, s, t) 

} 

functionhh(a, b, c, d, x, s, t) 

{ 

 returncmn(b ^ c ^ d, a, b, x, s, t) 

} 

functionii(a, b, c, d, x, s, t) 

{ 

 returncmn(c ^ (b | (~d)), a, b, x, s, t) 

} 

/*

 * Calculate the MD5 of an array of little-endian words, producing an array

 * of little-endian words.

 */ 

functioncoreMD5(x) 

{ 

 vara = 1732584193 

 varb = -271733879 

 varc = -1732584194 

 vard = 271733878 

 for(vari = 0; i < x.length; i += 16) 

 { 

  varolda = a 

  varoldb = b 

  varoldc = c 

  varoldd = d 

  a = ff(a, b, c, d, x[i+ 0], 7 , -680876936) 

  d = ff(d, a, b, c, x[i+ 1], 12, -389564586) 

  c = ff(c, d, a, b, x[i+ 2], 17, 606105819) 

  b = ff(b, c, d, a, x[i+ 3], 22, -1044525330) 

  a = ff(a, b, c, d, x[i+ 4], 7 , -176418897) 

  d = ff(d, a, b, c, x[i+ 5], 12, 1200080426) 

  c = ff(c, d, a, b, x[i+ 6], 17, -1473231341) 

  b = ff(b, c, d, a, x[i+ 7], 22, -45705983) 

  a = ff(a, b, c, d, x[i+ 8], 7 , 1770035416) 

  d = ff(d, a, b, c, x[i+ 9], 12, -1958414417) 

  c = ff(c, d, a, b, x[i+10], 17, -42063) 

  b = ff(b, c, d, a, x[i+11], 22, -1990404162) 

  a = ff(a, b, c, d, x[i+12], 7 , 1804603682) 

  d = ff(d, a, b, c, x[i+13], 12, -40341101) 

  c = ff(c, d, a, b, x[i+14], 17, -1502002290) 

  b = ff(b, c, d, a, x[i+15], 22, 1236535329) 

  a = gg(a, b, c, d, x[i+ 1], 5 , -165796510) 

  d = gg(d, a, b, c, x[i+ 6], 9 , -1069501632) 

  c = gg(c, d, a, b, x[i+11], 14, 643717713) 

  b = gg(b, c, d, a, x[i+ 0], 20, -373897302) 

  a = gg(a, b, c, d, x[i+ 5], 5 , -701558691) 

  d = gg(d, a, b, c, x[i+10], 9 , 38016083) 

  c = gg(c, d, a, b, x[i+15], 14, -660478335) 

  b = gg(b, c, d, a, x[i+ 4], 20, -405537848) 

  a = gg(a, b, c, d, x[i+ 9], 5 , 568446438) 

  d = gg(d, a, b, c, x[i+14], 9 , -1019803690) 

  c = gg(c, d, a, b, x[i+ 3], 14, -187363961) 

  b = gg(b, c, d, a, x[i+ 8], 20, 1163531501) 

  a = gg(a, b, c, d, x[i+13], 5 , -1444681467) 

  d = gg(d, a, b, c, x[i+ 2], 9 , -51403784) 

  c = gg(c, d, a, b, x[i+ 7], 14, 1735328473) 

  b = gg(b, c, d, a, x[i+12], 20, -1926607734) 

  a = hh(a, b, c, d, x[i+ 5], 4 , -378558) 

  d = hh(d, a, b, c, x[i+ 8], 11, -2022574463) 

  c = hh(c, d, a, b, x[i+11], 16, 1839030562) 

  b = hh(b, c, d, a, x[i+14], 23, -35309556) 

  a = hh(a, b, c, d, x[i+ 1], 4 , -1530992060) 

  d = hh(d, a, b, c, x[i+ 4], 11, 1272893353) 

  c = hh(c, d, a, b, x[i+ 7], 16, -155497632) 

  b = hh(b, c, d, a, x[i+10], 23, -1094730640) 

  a = hh(a, b, c, d, x[i+13], 4 , 681279174) 

  d = hh(d, a, b, c, x[i+ 0], 11, -358537222) 

  c = hh(c, d, a, b, x[i+ 3], 16, -722521979) 

  b = hh(b, c, d, a, x[i+ 6], 23, 76029189) 

  a = hh(a, b, c, d, x[i+ 9], 4 , -640364487) 

  d = hh(d, a, b, c, x[i+12], 11, -421815835) 

  c = hh(c, d, a, b, x[i+15], 16, 530742520) 

  b = hh(b, c, d, a, x[i+ 2], 23, -995338651) 

  a = ii(a, b, c, d, x[i+ 0], 6 , -198630844) 

  d = ii(d, a, b, c, x[i+ 7], 10, 1126891415) 

  c = ii(c, d, a, b, x[i+14], 15, -1416354905) 

  b = ii(b, c, d, a, x[i+ 5], 21, -57434055) 

  a = ii(a, b, c, d, x[i+12], 6 , 1700485571) 

  d = ii(d, a, b, c, x[i+ 3], 10, -1894986606) 

  c = ii(c, d, a, b, x[i+10], 15, -1051523) 

  b = ii(b, c, d, a, x[i+ 1], 21, -2054922799) 

  a = ii(a, b, c, d, x[i+ 8], 6 , 1873313359) 

  d = ii(d, a, b, c, x[i+15], 10, -30611744) 

  c = ii(c, d, a, b, x[i+ 6], 15, -1560198380) 

  b = ii(b, c, d, a, x[i+13], 21, 1309151649) 

  a = ii(a, b, c, d, x[i+ 4], 6 , -145523070) 

  d = ii(d, a, b, c, x[i+11], 10, -1120210379) 

  c = ii(c, d, a, b, x[i+ 2], 15, 718787259) 

  b = ii(b, c, d, a, x[i+ 9], 21, -343485551) 

  a = safe_add(a, olda) 

  b = safe_add(b, oldb) 

  c = safe_add(c, oldc) 

  d = safe_add(d, oldd) 

 } 

 return[a, b, c, d] 

} 

/*

 * Convert an array of little-endian words to a hex string.

 */ 

functionbinl2hex(binarray) 

{ 

 varhex_tab ="0123456789abcdef" 

 varstr ="" 

 for(vari = 0; i < binarray.length * 4; i++) 

 { 

  str += hex_tab.charAt((binarray[i>>2] >> ((i%4)*8+4)) & 0xF) + 

      hex_tab.charAt((binarray[i>>2] >> ((i%4)*8)) & 0xF) 

 } 

 returnstr 

} 

/*

 * Convert an array of little-endian words to a base64 encoded string.

 */ 

functionbinl2b64(binarray) 

{ 

 vartab ="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" 

 varstr ="" 

 for(vari = 0; i < binarray.length * 32; i += 6) 

 { 

  str += tab.charAt(((binarray[i>>5] << (i%32)) & 0x3F) | 

           ((binarray[i>>5+1] >> (32-i%32)) & 0x3F)) 

 } 

 returnstr 

} 

/*

 * Convert an 8-bit character string to a sequence of 16-word blocks, stored

 * as an array, and append appropriate padding for MD4/5 calculation.

 * If any of the characters are >255, the high byte is silently ignored.

 */ 

functionstr2binl(str) 

{ 

 varnblk = ((str.length + 8) >> 6) + 1// number of 16-word blocks 

 varblks =newArray(nblk * 16) 

 for(vari = 0; i < nblk * 16; i++) blks[i] = 0 

 for(vari = 0; i < str.length; i++) 

  blks[i>>2] |= (str.charCodeAt(i) & 0xFF) << ((i%4) * 8) 

 blks[i>>2] |= 0x80 << ((i%4) * 8) 

 blks[nblk*16-2] = str.length * 8 

 returnblks 

} 

/*

 * Convert a wide-character string to a sequence of 16-word blocks, stored as

 * an array, and append appropriate padding for MD4/5 calculation.

 */ 

functionstrw2binl(str) 

{ 

 varnblk = ((str.length + 4) >> 5) + 1// number of 16-word blocks 

 varblks =newArray(nblk * 16) 

 for(vari = 0; i < nblk * 16; i++) blks[i] = 0 

 for(vari = 0; i < str.length; i++) 

  blks[i>>1] |= str.charCodeAt(i) << ((i%2) * 16) 

 blks[i>>1] |= 0x80 << ((i%2) * 16) 

 blks[nblk*16-2] = str.length * 16 

 returnblks 

} 

/*

 * External interface

 */ 

functionhexMD5 (str) {returnbinl2hex(coreMD5( str2binl(str))) } 

functionhexMD5w(str) {returnbinl2hex(coreMD5(strw2binl(str))) } 

functionb64MD5 (str) {returnbinl2b64(coreMD5( str2binl(str))) } 

functionb64MD5w(str) {returnbinl2b64(coreMD5(strw2binl(str))) } 

/* Backward compatibility */ 

functioncalcMD5(str) {returnbinl2hex(coreMD5( str2binl(str))) } 

module.exports = { 

 hexMD5: hexMD5 

}