使用 JavaScript 的 md5 的较短版本..？

Question

我在 JSON 文件中有一个object array 。 object没有唯一的id所以我需要创建一个唯一的id或一个唯一的string 。

[
  {
    "name": "Jack Potts",
    "age": "56"
  }, {
    "name": "Rusty Carr",
    "age": "31"
  }
]

我知道我可以使用MD5 ，传入object ，但我将在 URL 中使用string ，所以我希望它更短。

而不是/people/3449c9e5e332f1dbb81505cd739fbf3f ，我更喜欢/people/1dbb81505类的东西。

它仍然需要是object的表示，因为我将再次从 URL 中查找此人。

有什么能产生string比MD5短string ..？

我猜 MD5 是我最好/唯一的选择，但我想我会问。

更新

我可能没有我想的那么清楚。 我不仅需要生成一个唯一的id 。 我不会用我生成的任何内容更新 JSON 文件。

我需要一种方法来获取有问题的object ，为其创建一个 URL，然后在访问该 URL 时使用该 URL 返回array该object 。

据我所知，如果您一遍又一遍地将相同的string传递给MD5 ，它将始终返回相同的 MD5 string因为它是一个表示。 出于同样的原因，人们在将密码存储在数据库中时不使用它吗？

也许 MD5 很好，我只是想可能会产生一个较短的string来表示数据。 这是我的问题。

更新 2

array的人可能会改变。 可能会添加和删除人员，因此无法使用array索引。

Answer 1

如果您只想要一个更短的 MD5 输出，但对唯一性感到满意，只需将其截断为您需要的长度，那么每一位与任何其他位一样随机，也就是说，您选择的位的任何子集都与其他位一样好子集。

但是要意识到，如果两个名称相同，您将获得相同的哈希值。

由于您必须意识到散列越短，冲突的变化越大，您正在权衡散列长度与唯一性，这还不错，只要确保您有足够的唯一性来满足您的需求。

Answer 2

使用以下函数：

function generateUID() {
    var firstPart = (Math.random() * 46656) | 0;
    var secondPart = (Math.random() * 46656) | 0;
    firstPart = ("000" + firstPart.toString(36)).slice(-3);
    secondPart = ("000" + secondPart.toString(36)).slice(-3);
    return firstPart + secondPart;
}

6 个字符的字母数字序列足以随机索引 10k 集合（366 = 22 亿和 363 = 46656）。

Answer 3

我建议你使用 sha1，它处理一个相对较短的哈希。 假设您的数据集相对有限 < 1000000000000 ......等等......项目发生碰撞的可能性应该很小。

https://github.com/emn178/js-sha1是一个不错的库

编辑修改了它以使其更短

它现在执行一个子字符串，+一个应该可靠的碰撞检测修改，只要项目的顺序在它们具有 smae 值时不会改变。 但是话又说回来，如果它们具有相同的值，那应该没关系;-)

 /* * [js-sha1]{@link https://github.com/emn178/js-sha1} * * @version 0.4.1 * @author Chen, Yi-Cyuan [emn178@gmail.com] * @copyright Chen, Yi-Cyuan 2014-2016 * @license MIT */ /*jslint bitwise: true */ (function() { 'use strict'; var root = typeof window === 'object' ? window : {}; var NODE_JS = !root.JS_SHA1_NO_NODE_JS && typeof process === 'object' && process.versions && process.versions.node; if (NODE_JS) { root = global; } var COMMON_JS = !root.JS_SHA1_NO_COMMON_JS && typeof module === 'object' && module.exports; var AMD = typeof define === 'function' && define.amd; var HEX_CHARS = '0123456789abcdef'.split(''); var EXTRA = [-2147483648, 8388608, 32768, 128]; var SHIFT = [24, 16, 8, 0]; var OUTPUT_TYPES = ['hex', 'array', 'digest', 'arrayBuffer']; var blocks = []; var createOutputMethod = function (outputType) { return function (message) { return new Sha1(true).update(message)[outputType](); }; }; var createMethod = function () { var method = createOutputMethod('hex'); if (NODE_JS) { method = nodeWrap(method); } method.create = function () { return new Sha1(); }; method.update = function (message) { return method.create().update(message); }; for (var i = 0; i < OUTPUT_TYPES.length; ++i) { var type = OUTPUT_TYPES[i]; method[type] = createOutputMethod(type); } return method; }; var nodeWrap = function (method) { var crypto = require('crypto'); var Buffer = require('buffer').Buffer; var nodeMethod = function (message) { if (typeof message === 'string') { return crypto.createHash('sha1').update(message, 'utf8').digest('hex'); } else if (message.constructor === ArrayBuffer) { message = new Uint8Array(message); } else if (message.length === undefined) { return method(message); } return crypto.createHash('sha1').update(new Buffer(message)).digest('hex'); }; return nodeMethod; }; function Sha1(sharedMemory) { if (sharedMemory) { blocks[0] = blocks[16] = blocks[1] = blocks[2] = blocks[3] = blocks[4] = blocks[5] = blocks[6] = blocks[7] = blocks[8] = blocks[9] = blocks[10] = blocks[11] = blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0; this.blocks = blocks; } else { this.blocks = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]; } this.h0 = 0x67452301; this.h1 = 0xEFCDAB89; this.h2 = 0x98BADCFE; this.h3 = 0x10325476; this.h4 = 0xC3D2E1F0; this.block = this.start = this.bytes = 0; this.finalized = this.hashed = false; this.first = true; } Sha1.prototype.update = function (message) { if (this.finalized) { return; } var notString = typeof(message) !== 'string'; if (notString && message.constructor === root.ArrayBuffer) { message = new Uint8Array(message); } var code, index = 0, i, length = message.length || 0, blocks = this.blocks; while (index < length) { if (this.hashed) { this.hashed = false; blocks[0] = this.block; blocks[16] = blocks[1] = blocks[2] = blocks[3] = blocks[4] = blocks[5] = blocks[6] = blocks[7] = blocks[8] = blocks[9] = blocks[10] = blocks[11] = blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0; } if(notString) { for (i = this.start; index < length && i < 64; ++index) { blocks[i >> 2] |= message[index] << SHIFT[i++ & 3]; } } else { for (i = this.start; index < length && i < 64; ++index) { code = message.charCodeAt(index); if (code < 0x80) { blocks[i >> 2] |= code << SHIFT[i++ & 3]; } else if (code < 0x800) { blocks[i >> 2] |= (0xc0 | (code >> 6)) << SHIFT[i++ & 3]; blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3]; } else if (code < 0xd800 || code >= 0xe000) { blocks[i >> 2] |= (0xe0 | (code >> 12)) << SHIFT[i++ & 3]; blocks[i >> 2] |= (0x80 | ((code >> 6) & 0x3f)) << SHIFT[i++ & 3]; blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3]; } else { code = 0x10000 + (((code & 0x3ff) << 10) | (message.charCodeAt(++index) & 0x3ff)); blocks[i >> 2] |= (0xf0 | (code >> 18)) << SHIFT[i++ & 3]; blocks[i >> 2] |= (0x80 | ((code >> 12) & 0x3f)) << SHIFT[i++ & 3]; blocks[i >> 2] |= (0x80 | ((code >> 6) & 0x3f)) << SHIFT[i++ & 3]; blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3]; } } } this.lastByteIndex = i; this.bytes += i - this.start; if (i >= 64) { this.block = blocks[16]; this.start = i - 64; this.hash(); this.hashed = true; } else { this.start = i; } } return this; }; Sha1.prototype.finalize = function () { if (this.finalized) { return; } this.finalized = true; var blocks = this.blocks, i = this.lastByteIndex; blocks[16] = this.block; blocks[i >> 2] |= EXTRA[i & 3]; this.block = blocks[16]; if (i >= 56) { if (!this.hashed) { this.hash(); } blocks[0] = this.block; blocks[16] = blocks[1] = blocks[2] = blocks[3] = blocks[4] = blocks[5] = blocks[6] = blocks[7] = blocks[8] = blocks[9] = blocks[10] = blocks[11] = blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0; } blocks[15] = this.bytes << 3; this.hash(); }; Sha1.prototype.hash = function () { var a = this.h0, b = this.h1, c = this.h2, d = this.h3, e = this.h4; var f, j, t, blocks = this.blocks; for(j = 16; j < 80; ++j) { t = blocks[j - 3] ^ blocks[j - 8] ^ blocks[j - 14] ^ blocks[j - 16]; blocks[j] = (t << 1) | (t >>> 31); } for(j = 0; j < 20; j += 5) { f = (b & c) | ((~b) & d); t = (a << 5) | (a >>> 27); e = t + f + e + 1518500249 + blocks[j] << 0; b = (b << 30) | (b >>> 2); f = (a & b) | ((~a) & c); t = (e << 5) | (e >>> 27); d = t + f + d + 1518500249 + blocks[j + 1] << 0; a = (a << 30) | (a >>> 2); f = (e & a) | ((~e) & b); t = (d << 5) | (d >>> 27); c = t + f + c + 1518500249 + blocks[j + 2] << 0; e = (e << 30) | (e >>> 2); f = (d & e) | ((~d) & a); t = (c << 5) | (c >>> 27); b = t + f + b + 1518500249 + blocks[j + 3] << 0; d = (d << 30) | (d >>> 2); f = (c & d) | ((~c) & e); t = (b << 5) | (b >>> 27); a = t + f + a + 1518500249 + blocks[j + 4] << 0; c = (c << 30) | (c >>> 2); } for(; j < 40; j += 5) { f = b ^ c ^ d; t = (a << 5) | (a >>> 27); e = t + f + e + 1859775393 + blocks[j] << 0; b = (b << 30) | (b >>> 2); f = a ^ b ^ c; t = (e << 5) | (e >>> 27); d = t + f + d + 1859775393 + blocks[j + 1] << 0; a = (a << 30) | (a >>> 2); f = e ^ a ^ b; t = (d << 5) | (d >>> 27); c = t + f + c + 1859775393 + blocks[j + 2] << 0; e = (e << 30) | (e >>> 2); f = d ^ e ^ a; t = (c << 5) | (c >>> 27); b = t + f + b + 1859775393 + blocks[j + 3] << 0; d = (d << 30) | (d >>> 2); f = c ^ d ^ e; t = (b << 5) | (b >>> 27); a = t + f + a + 1859775393 + blocks[j + 4] << 0; c = (c << 30) | (c >>> 2); } for(; j < 60; j += 5) { f = (b & c) | (b & d) | (c & d); t = (a << 5) | (a >>> 27); e = t + f + e - 1894007588 + blocks[j] << 0; b = (b << 30) | (b >>> 2); f = (a & b) | (a & c) | (b & c); t = (e << 5) | (e >>> 27); d = t + f + d - 1894007588 + blocks[j + 1] << 0; a = (a << 30) | (a >>> 2); f = (e & a) | (e & b) | (a & b); t = (d << 5) | (d >>> 27); c = t + f + c - 1894007588 + blocks[j + 2] << 0; e = (e << 30) | (e >>> 2); f = (d & e) | (d & a) | (e & a); t = (c << 5) | (c >>> 27); b = t + f + b - 1894007588 + blocks[j + 3] << 0; d = (d << 30) | (d >>> 2); f = (c & d) | (c & e) | (d & e); t = (b << 5) | (b >>> 27); a = t + f + a - 1894007588 + blocks[j + 4] << 0; c = (c << 30) | (c >>> 2); } for(; j < 80; j += 5) { f = b ^ c ^ d; t = (a << 5) | (a >>> 27); e = t + f + e - 899497514 + blocks[j] << 0; b = (b << 30) | (b >>> 2); f = a ^ b ^ c; t = (e << 5) | (e >>> 27); d = t + f + d - 899497514 + blocks[j + 1] << 0; a = (a << 30) | (a >>> 2); f = e ^ a ^ b; t = (d << 5) | (d >>> 27); c = t + f + c - 899497514 + blocks[j + 2] << 0; e = (e << 30) | (e >>> 2); f = d ^ e ^ a; t = (c << 5) | (c >>> 27); b = t + f + b - 899497514 + blocks[j + 3] << 0; d = (d << 30) | (d >>> 2); f = c ^ d ^ e; t = (b << 5) | (b >>> 27); a = t + f + a - 899497514 + blocks[j + 4] << 0; c = (c << 30) | (c >>> 2); } this.h0 = this.h0 + a << 0; this.h1 = this.h1 + b << 0; this.h2 = this.h2 + c << 0; this.h3 = this.h3 + d << 0; this.h4 = this.h4 + e << 0; }; Sha1.prototype.hex = function () { this.finalize(); var h0 = this.h0, h1 = this.h1, h2 = this.h2, h3 = this.h3, h4 = this.h4; return HEX_CHARS[(h0 >> 28) & 0x0F] + HEX_CHARS[(h0 >> 24) & 0x0F] + HEX_CHARS[(h0 >> 20) & 0x0F] + HEX_CHARS[(h0 >> 16) & 0x0F] + HEX_CHARS[(h0 >> 12) & 0x0F] + HEX_CHARS[(h0 >> 8) & 0x0F] + HEX_CHARS[(h0 >> 4) & 0x0F] + HEX_CHARS[h0 & 0x0F] + HEX_CHARS[(h1 >> 28) & 0x0F] + HEX_CHARS[(h1 >> 24) & 0x0F] + HEX_CHARS[(h1 >> 20) & 0x0F] + HEX_CHARS[(h1 >> 16) & 0x0F] + HEX_CHARS[(h1 >> 12) & 0x0F] + HEX_CHARS[(h1 >> 8) & 0x0F] + HEX_CHARS[(h1 >> 4) & 0x0F] + HEX_CHARS[h1 & 0x0F] + HEX_CHARS[(h2 >> 28) & 0x0F] + HEX_CHARS[(h2 >> 24) & 0x0F] + HEX_CHARS[(h2 >> 20) & 0x0F] + HEX_CHARS[(h2 >> 16) & 0x0F] + HEX_CHARS[(h2 >> 12) & 0x0F] + HEX_CHARS[(h2 >> 8) & 0x0F] + HEX_CHARS[(h2 >> 4) & 0x0F] + HEX_CHARS[h2 & 0x0F] + HEX_CHARS[(h3 >> 28) & 0x0F] + HEX_CHARS[(h3 >> 24) & 0x0F] + HEX_CHARS[(h3 >> 20) & 0x0F] + HEX_CHARS[(h3 >> 16) & 0x0F] + HEX_CHARS[(h3 >> 12) & 0x0F] + HEX_CHARS[(h3 >> 8) & 0x0F] + HEX_CHARS[(h3 >> 4) & 0x0F] + HEX_CHARS[h3 & 0x0F] + HEX_CHARS[(h4 >> 28) & 0x0F] + HEX_CHARS[(h4 >> 24) & 0x0F] + HEX_CHARS[(h4 >> 20) & 0x0F] + HEX_CHARS[(h4 >> 16) & 0x0F] + HEX_CHARS[(h4 >> 12) & 0x0F] + HEX_CHARS[(h4 >> 8) & 0x0F] + HEX_CHARS[(h4 >> 4) & 0x0F] + HEX_CHARS[h4 & 0x0F]; }; Sha1.prototype.toString = Sha1.prototype.hex; Sha1.prototype.digest = function () { this.finalize(); var h0 = this.h0, h1 = this.h1, h2 = this.h2, h3 = this.h3, h4 = this.h4; return [ (h0 >> 24) & 0xFF, (h0 >> 16) & 0xFF, (h0 >> 8) & 0xFF, h0 & 0xFF, (h1 >> 24) & 0xFF, (h1 >> 16) & 0xFF, (h1 >> 8) & 0xFF, h1 & 0xFF, (h2 >> 24) & 0xFF, (h2 >> 16) & 0xFF, (h2 >> 8) & 0xFF, h2 & 0xFF, (h3 >> 24) & 0xFF, (h3 >> 16) & 0xFF, (h3 >> 8) & 0xFF, h3 & 0xFF, (h4 >> 24) & 0xFF, (h4 >> 16) & 0xFF, (h4 >> 8) & 0xFF, h4 & 0xFF ]; }; Sha1.prototype.array = Sha1.prototype.digest; Sha1.prototype.arrayBuffer = function () { this.finalize(); var buffer = new ArrayBuffer(20); var dataView = new DataView(buffer); dataView.setUint32(0, this.h0); dataView.setUint32(4, this.h1); dataView.setUint32(8, this.h2); dataView.setUint32(12, this.h3); dataView.setUint32(16, this.h4); return buffer; }; var exports = createMethod(); if (COMMON_JS) { module.exports = exports; } else { root.sha1 = exports; if (AMD) { define(function () { return exports; }); } } })(); +function() { var HASHLENGTH = 5; document.getElementById('clickme').onclick = function() { // get all the values as objects var values = JSON.parse(document.getElementById('sample').value); for (var c = 0; c < values.length; c++) { // Hash it and substring it given the hashlength values[c].hash = sha1(JSON.stringify(values[c])).substring(0,HASHLENGTH); // If you don't need the collision detection, you can just remove these loops. // check for collisions for(var i = 0;i < c; i++) { // collision detected. add a dependable value to get a new hash. if(values[i].hash == values[c].hash) { if(values[c].hasOwnProperty('_change')) { values[c]._change = sha1(values[c]._change); } else { values[c]._change = sha1(values[c].hash); } c--;break; // return to same thing for a rehash } } } console.log(JSON.stringify(values,null,4)); } }();

 textarea { width:100%;height:200px;}

 <button id="clickme"> Parse </button> <textarea id="sample"> [ { "name": "Jack Potts", "age": "56" }, { "name": "Rusty Carr", "age": "31" }, { "name": "Rusty Carr", "age": "31" }, { "name": "Rusty Carr", "age": "31" }, { "name": "Rusty Carr", "age": "31" }, { "name": "Rusty Carr", "age": "31" }, { "name": "Rusty Carr", "age": "31" } ] </textarea>

Answer 4

我不会用我生成的任何内容更新 JSON 文件。

我需要一种方法来获取有问题的对象，为其创建一个 URL，然后在访问该 URL 时使用该 URL 返回数组中的该对象。

然后使用数组中对象的索引：这样people/0将返回{"name": "Jack Potts", "age": "56"} ， people/1将返回{"name": "Rusty Carr", "age": "31"}等等...

Answer 5

这是用于获取 MD5 哈希的原生 JavaScript 代码，缩短为所需长度。 请注意，哈希值越短，发生冲突的可能性就越大。

var md5 = function(d){var r = M(V(Y(X(d),8*d.length)));return r.toLowerCase()};function M(d){for(var _,m="0123456789ABCDEF",f="",r=0;r<d.length;r++)_=d.charCodeAt(r),f+=m.charAt(_>>>4&15)+m.charAt(15&_);return f}function X(d){for(var _=Array(d.length>>2),m=0;m<_.length;m++)_[m]=0;for(m=0;m<8*d.length;m+=8)_[m>>5]|=(255&d.charCodeAt(m/8))<<m%32;return _}function V(d){for(var _="",m=0;m<32*d.length;m+=8)_+=String.fromCharCode(d[m>>5]>>>m%32&255);return _}function Y(d,_){d[_>>5]|=128<<_%32,d[14+(_+64>>>9<<4)]=_;for(var m=1732584193,f=-271733879,r=-1732584194,i=271733878,n=0;n<d.length;n+=16){var h=m,t=f,g=r,e=i;f=md5_ii(f=md5_ii(f=md5_ii(f=md5_ii(f=md5_hh(f=md5_hh(f=md5_hh(f=md5_hh(f=md5_gg(f=md5_gg(f=md5_gg(f=md5_gg(f=md5_ff(f=md5_ff(f=md5_ff(f=md5_ff(f,r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+0],7,-680876936),f,r,d[n+1],12,-389564586),m,f,d[n+2],17,606105819),i,m,d[n+3],22,-1044525330),r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+4],7,-176418897),f,r,d[n+5],12,1200080426),m,f,d[n+6],17,-1473231341),i,m,d[n+7],22,-45705983),r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+8],7,1770035416),f,r,d[n+9],12,-1958414417),m,f,d[n+10],17,-42063),i,m,d[n+11],22,-1990404162),r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+12],7,1804603682),f,r,d[n+13],12,-40341101),m,f,d[n+14],17,-1502002290),i,m,d[n+15],22,1236535329),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+1],5,-165796510),f,r,d[n+6],9,-1069501632),m,f,d[n+11],14,643717713),i,m,d[n+0],20,-373897302),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+5],5,-701558691),f,r,d[n+10],9,38016083),m,f,d[n+15],14,-660478335),i,m,d[n+4],20,-405537848),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+9],5,568446438),f,r,d[n+14],9,-1019803690),m,f,d[n+3],14,-187363961),i,m,d[n+8],20,1163531501),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+13],5,-1444681467),f,r,d[n+2],9,-51403784),m,f,d[n+7],14,1735328473),i,m,d[n+12],20,-1926607734),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+5],4,-378558),f,r,d[n+8],11,-2022574463),m,f,d[n+11],16,1839030562),i,m,d[n+14],23,-35309556),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+1],4,-1530992060),f,r,d[n+4],11,1272893353),m,f,d[n+7],16,-155497632),i,m,d[n+10],23,-1094730640),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+13],4,681279174),f,r,d[n+0],11,-358537222),m,f,d[n+3],16,-722521979),i,m,d[n+6],23,76029189),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+9],4,-640364487),f,r,d[n+12],11,-421815835),m,f,d[n+15],16,530742520),i,m,d[n+2],23,-995338651),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+0],6,-198630844),f,r,d[n+7],10,1126891415),m,f,d[n+14],15,-1416354905),i,m,d[n+5],21,-57434055),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+12],6,1700485571),f,r,d[n+3],10,-1894986606),m,f,d[n+10],15,-1051523),i,m,d[n+1],21,-2054922799),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+8],6,1873313359),f,r,d[n+15],10,-30611744),m,f,d[n+6],15,-1560198380),i,m,d[n+13],21,1309151649),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+4],6,-145523070),f,r,d[n+11],10,-1120210379),m,f,d[n+2],15,718787259),i,m,d[n+9],21,-343485551),m=safe_add(m,h),f=safe_add(f,t),r=safe_add(r,g),i=safe_add(i,e)}return Array(m,f,r,i)}function md5_cmn(d,_,m,f,r,i){return safe_add(bit_rol(safe_add(safe_add(_,d),safe_add(f,i)),r),m)}function md5_ff(d,_,m,f,r,i,n){return md5_cmn(_&m|~_&f,d,_,r,i,n)}function md5_gg(d,_,m,f,r,i,n){return md5_cmn(_&f|m&~f,d,_,r,i,n)}function md5_hh(d,_,m,f,r,i,n){return md5_cmn(_^m^f,d,_,r,i,n)}function md5_ii(d,_,m,f,r,i,n){return md5_cmn(m^(_|~f),d,_,r,i,n)}function safe_add(d,_){var m=(65535&d)+(65535&_);return(d>>16)+(_>>16)+(m>>16)<<16|65535&m}function bit_rol(d,_){return d<<_|d>>>32-_}

function tinymd5(str, length) {
    length = length || 16;
    str = window.btoa(md5(str)).replace(/[aiueoAIUEO\+\/]/g, '').substring(0, length);
    if(str.length < length) {
        str += Array(length - str.length).join('=');
    }
    return str;
}

// example usage:
var shortHash = tinymd5(JSON.stringify(someObj), 16);

md5 函数来自https://stackoverflow.com/a/33486055/7475450

tinymd5 函数是基于https://rolandeckert.com/notes/md5 的代码转换为 JavaScript