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JavaScript中使用较短的MD5版本是什么？

javascriptjsonmd5
3
我在一个JSON文件中有一个对象的数组。这些对象没有唯一的id，所以我需要创建一个唯一的id或唯一的字符串。
[
  {
    "name": "Jack Potts",
    "age": "56"
  }, {
    "name": "Rusty Carr",
    "age": "31"
  }
]

我知道我可以使用MD5，传递object，但我将在URL中使用string，因此我希望它更短一些。与其使用/people/3449c9e5e332f1dbb81505cd739fbf3f，我更喜欢像/people/1dbb81505这样的东西。它仍然需要是object的表示，因为我将再次从URL查找该人。有没有比MD5 string更短的string生成方式？我猜MD5是我最好/唯一的选择，但我想问问。更新：我可能没有表达清楚。我不仅需要生成一个唯一的id，我也不会使用我生成的任何内容更新JSON文件。
我需要一种方法来获取所需的object，创建一个URL，然后当访问该URL时，使用该URL返回到array中的object。
据我所知，如果您多次传递相同的string给MD5，它将始终返回相同的MD5 string，因为它是一个representation。人们不是出于同样的原因在数据库中存储密码时使用它吗？
也许MD5很好，我只是想知道是否有一些可以生成较短string的东西，这是数据的representation。这是我的问题。 更新2 array中的人可能会改变。人员可能会增加和删除，因此使用array索引将无法起作用。
MD5长度为256位...所以不行...那CRC32呢？ - Jaromanda X
1
哈希函数的结果越短，发生冲突的可能性就越大。 - CBroe
只使用整数不就可以了吗？为什么长度很重要呢？ - Dave3of5
我已经更新了问题，我不仅需要一个唯一的ID。 - Stephen Last
@JaromandaX 一种方法就可以了... 当我再次查找对象时，我可以为数组中的每个对象生成MD5哈希，并在URL中搜索哈希。 - Stephen Last
显示剩余2条评论
6个回答
3
如果你只需要比MD5更短的输出，但对唯一性感到满意，那么只需截取所需的长度即可。每个位都像任何其他位一样随机，也就是说，您选择的任何位的子集与任何其他子集一样好。
但请注意，如果两个名称相同，则会得到相同的哈希值。
正如您必须意识到的那样，哈希越短，发生碰撞的可能性就越高。您正在进行哈希长度与唯一性之间的权衡，这并不坏，只要确保您具有足够的唯一性来满足您的需求。
1
我喜欢这个答案...所以我可以使用MD5并且只需str.substring(0, 10)（例如）。现在我可以看到我的问题表述得不是很好，但这个答案正是我需要的。 - Stephen Last
是的，可以在字符串表示中，例如在问题中。 - zaph
0

我建议你使用sha1，它能够生成一个相对较短的哈希值。假设你的数据集相对有限< 1000000000000...等等...项，碰撞的几率应该很小。

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

编辑将其修改得更短了

现在它进行了子字符串处理，以及碰撞检测的修改，只要项目的顺序不变，就能够可靠地工作。但如果它们具有相同的值，那么这也无关紧要；-）

/*
 * [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>

似乎产生的哈希值与MD5一样长，甚至更长。我的问题是关于一个比MD5更短的版本。 - Stephen Last
通常所做的是哈希的子字符串。因此，如果您做一个5个字母的子字符串，您有16x16x16x16x16（1048576）种字符组合的可能性。使用JavaScript数据集可以提供足够的灵活性。如果发生冲突，您可以轻松地检查和修改对象，通过添加值使其不可碰撞。我将修改我的示例以显示这一点。 - Tschallacka
@StephenLast 我用子字符串和双重碰撞检测修改了我的示例。这应该足够强大，适用于实际的实现。 - Tschallacka
1
  1. 始终使用经过充分验证的库中的方法，而不是代码。
  2. 什么是双重碰撞检测，请解释。
 - zaph
我使用了一个经过充分验证的库中的sha1代码，您可以轻松地看到，我甚至提供了链接。此外，“code”是一个简单的子字符串。双重碰撞检测使得每个项目都会获得第二个计算出的唯一哈希值，具体取决于出现点。第一次基于计算出的哈希值，第二次发现双倍基于对象中现有的哈希值，但如果您阅读了代码，您会发现他可以删除它，因为op声明允许重复项具有相同的哈希值。我只是将其添加为一个功能。 - Tschallacka
@Tschallacka 谢谢。看你的代码很有趣。但是，简单的答案就是使用 str.substring() 并理解你必须接受的权衡，这正如 @zaph 所说的那样。 - Stephen Last
0
我不会用生成的任何内容更新JSON文件。 我需要一种方法来获取相关对象，为其创建一个URL，然后当访问该URL时，使用该URL返回数组中的对象。 然后使用对象在数组中的索引：这样，people/0将返回{"name": "Jack Potts", "age": "56"}，people/1将返回{"name": "Rusty Carr", "age": "31"}，以此类推...
只要 JSON 数组中的人员不改变，那么这个方法就可以工作，但在我的情况下，他们可能会改变。人员可能会被添加和删除，URL 需要指向正确的人。我会更新我的问题 - 抱歉！ - Stephen Last
0

也许使用3125个字符可以解决问题：

const md5=str=>{var a=(r,t)=>r+t&0xffffffff,l=(r,t)=>{var e=r[0],n=r[1],o=r[2],l=r[3],e=h(e,n,o,l,t[0],7,-0x28955b88),l=h(l,e,n,o,t[1],12,-0x173848aa),o=h(o,l,e,n,t[2],17,0x242070db),n=h(n,o,l,e,t[3],22,-0x3e423112);e=h(e,n,o,l,t[4],7,-0xa83f051),l=h(l,e,n,o,t[5],12,0x4787c62a),o=h(o,l,e,n,t[6],17,-0x57cfb9ed),n=h(n,o,l,e,t[7],22,-0x2b96aff),e=h(e,n,o,l,t[8],7,0x698098d8),l=h(l,e,n,o,t[9],12,-0x74bb0851),o=h(o,l,e,n,t[10],17,-42063),n=h(n,o,l,e,t[11],22,-0x76a32842),e=h(e,n,o,l,t[12],7,0x6b901122),l=h(l,e,n,o,t[13],12,-0x2678e6d),o=h(o,l,e,n,t[14],17,-0x5986bc72),n=h(n,o,l,e,t[15],22,0x49b40821),e=c(e,n,o,l,t[1],5,-0x9e1da9e),l=c(l,e,n,o,t[6],9,-0x3fbf4cc0),o=c(o,l,e,n,t[11],14,0x265e5a51),n=c(n,o,l,e,t[0],20,-0x16493856),e=c(e,n,o,l,t[5],5,-0x29d0efa3),l=c(l,e,n,o,t[10],9,0x2441453),o=c(o,l,e,n,t[15],14,-0x275e197f),n=c(n,o,l,e,t[4],20,-0x182c0438),e=c(e,n,o,l,t[9],5,0x21e1cde6),l=c(l,e,n,o,t[14],9,-0x3cc8f82a),o=c(o,l,e,n,t[3],14,-0xb2af279),n=c(n,o,l,e,t[8],20,0x455a14ed),e=c(e,n,o,l,t[13],5,-0x561c16fb),l=c(l,e,n,o,t[2],9,-0x3105c08),o=c(o,l,e,n,t[7],14,0x676f02d9),n=c(n,o,l,e,t[12],20,-0x72d5b376),e=d(e,n,o,l,t[5],4,-378558),l=d(l,e,n,o,t[8],11,-0x788e097f),o=d(o,l,e,n,t[11],16,0x6d9d6122),n=d(n,o,l,e,t[14],23,-0x21ac7f4),e=d(e,n,o,l,t[1],4,-0x5b4115bc),l=d(l,e,n,o,t[4],11,0x4bdecfa9),o=d(o,l,e,n,t[7],16,-0x944b4a0),n=d(n,o,l,e,t[10],23,-0x41404390),e=d(e,n,o,l,t[13],4,0x289b7ec6),l=d(l,e,n,o,t[0],11,-0x155ed806),o=d(o,l,e,n,t[3],16,-0x2b10cf7b),n=d(n,o,l,e,t[6],23,0x4881d05),e=d(e,n,o,l,t[9],4,-0x262b2fc7),l=d(l,e,n,o,t[12],11,-0x1924661b),o=d(o,l,e,n,t[15],16,0x1fa27cf8),n=d(n,o,l,e,t[2],23,-0x3b53a99b),e=g(e,n,o,l,t[0],6,-0xbd6ddbc),l=g(l,e,n,o,t[7],10,0x432aff97),o=g(o,l,e,n,t[14],15,-0x546bdc59),n=g(n,o,l,e,t[5],21,-0x36c5fc7),e=g(e,n,o,l,t[12],6,0x655b59c3),l=g(l,e,n,o,t[3],10,-0x70f3336e),o=g(o,l,e,n,t[10],15,-0x100b83),n=g(n,o,l,e,t[1],21,-0x7a7ba22f),e=g(e,n,o,l,t[8],6,0x6fa87e4f),l=g(l,e,n,o,t[15],10,-0x1d31920),o=g(o,l,e,n,t[6],15,-0x5cfebcec),n=g(n,o,l,e,t[13],21,0x4e0811a1),e=g(e,n,o,l,t[4],6,-0x8ac817e),l=g(l,e,n,o,t[11],10,-0x42c50dcb),o=g(o,l,e,n,t[2],15,0x2ad7d2bb),n=g(n,o,l,e,t[9],21,-0x14792c6f),r[0]=a(e,r[0]),r[1]=a(n,r[1]),r[2]=a(o,r[2]),r[3]=a(l,r[3])},f=(r,t,e,n,o,l)=>(t=a(a(t,r),a(n,l)),a(t<<o|t>>>32-o,e));let h=(r,t,e,n,o,l,a)=>f(t&e|~t&n,r,t,o,l,a),c=(r,t,e,n,o,l,a)=>f(t&n|e&~n,r,t,o,l,a),d=(r,t,e,n,o,l,a)=>f(t^e^n,r,t,o,l,a),g=(r,t,e,n,o,l,a)=>f(e^(t|~n),r,t,o,l,a);var n="0123456789abcdef".split("");return(t=>{for(let r=0;r<t.length;r++)t[r]=(r=>{let t="",e=0;for(;e<4;e++)t+=n[r>>8*e+4&15]+n[r>>8*e&15];return t})(t[r]);return t.join("")})((r=>{let t=r.length,e=[0x67452301,-0x10325477,-0x67452302,0x10325476],n;for(n=64;n<=r.length;n+=64)l(e,(r=>{let t=[],e;for(e=0;e<64;e+=4)t[e>>2]=r.charCodeAt(e)+(r.charCodeAt(e+1)<<8)+(r.charCodeAt(e+2)<<16)+(r.charCodeAt(e+3)<<24);return t})(r.substring(n-64,n)));r=r.substring(n-64);let o=[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0];for(n=0;n<r.length;n++)o[n>>2]|=r.charCodeAt(n)<<(n%4<<3);if(o[n>>2]|=128<<(n%4<<3),55<n)for(l(e,o),n=0;n<16;n++)o[n]=0;return o[14]=8*t,l(e,o),e})("string"==typeof str?str:""+str))};
我认为他们想要哈希值更短，而不是函数。 - Moritz Ringler
0

下面是获取MD5哈希值的本地JavaScript代码，可以缩短到所需的长度。请注意，哈希越短，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://dev59.com/z2Uq5IYBdhLWcg3wKtRL#33486055

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

0
请使用以下函数：
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;
}

一个由6个字母和数字混合组成的序列已足够随机索引一个包含1万项的集合（366 = 22亿，363 = 46656）。
1
我已经更新了问题，我不仅需要一个唯一的ID，它还需要成为对象的表示，就像MD5一样。 - Stephen Last
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