Javascript 中的高密度随机字符串

发布于 2024-11-28 10:55:44 字数 691 浏览 0 评论 0原文

我目前正在使用此函数在 Javascript 中生成 UUID（创建 GUID / UUID在 JavaScript 中？）：

lucid.uuid = function() {
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
        return v.toString(16);
    });
}

我知道所有随机性仅来自 Javascript 的 Math.random() 函数，并且我不关心它是否符合 UUID 的 RFC。我想要的是将尽可能多的随机性打包到 Javascript 字符串中尽可能少的字节中。上面的函数给出了大约 128 位的随机性。在 Javascript 中，多小的字符串（以 HTTP POST 中通过线路发送的 UTF8 字节来测量）可以容纳 128 位？我将如何生成这样的字符串？

编辑：当发送到服务器时，该字符串将成为 JSON 对象的一部分，因此需要在字符串中转义的字符并不是很有帮助。

原文

I'm currently generating UUIDs in Javascript with this function (Create GUID / UUID in JavaScript?):

lucid.uuid = function() {
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
        return v.toString(16);
    });
}

I understand that all the randomness is only coming from Javascript's Math.random() function, and I don't care if it meets an RFC for a UUID. What I want is to pack as much randomness into as few bytes as possible in a Javascript string. The above function gives about 128 bits of randomness. How small of a string (as measured in UTF8 bytes sent over the wire in an HTTP POST) could I fit 128 bits into in Javascript? And how would I generate such a string?

Edit: This string will be part of a JSON object when sent to the server, so characters that need to be escaped in a string are not very helpful.

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骄兵必败 2024-12-05 10:55:44

这是我想出的一个潜在功能。种子字符串是一组未保留的 URL 字符（共 66 个）。我在随机性前添加了大约一年的 1 秒分辨率时间戳数据，这很有用，因为我的特定应用程序的冲突空间只会随着时间的推移而相当缓慢地填充（最多每秒生成几百个）一个极端的例子）。

uuidDense = function() {
    var seed = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~';

    //Start the UUID with 4 digits of seed from the current date/time in seconds
    //(which is almost a year worth of second data).
    var seconds = Math.floor((new Date().getTime())/1000);

    var ret = seed[seconds % seed.length];
    ret += seed[Math.floor(seconds/=seed.length) % seed.length];
    ret += seed[Math.floor(seconds/=seed.length) % seed.length];
    ret += seed[Math.floor(seconds/=seed.length) % seed.length];

    for(var i = 0; i < 8; i++)
        ret += seed[Math.random()*seed.length|0];

    return ret;
}

想法？

Here is one potential function I came up with. The seed string is the set of unreserved URL characters (66 of them). I prefix the randomness with about a year's worth of 1-second-resolution timestamp data, which is helpful since the collision space for my particular application is only filled up reasonably slowly over time (only at MOST a few hundred of these generated per second in an extreme case).

uuidDense = function() {
    var seed = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~';

    //Start the UUID with 4 digits of seed from the current date/time in seconds
    //(which is almost a year worth of second data).
    var seconds = Math.floor((new Date().getTime())/1000);

    var ret = seed[seconds % seed.length];
    ret += seed[Math.floor(seconds/=seed.length) % seed.length];
    ret += seed[Math.floor(seconds/=seed.length) % seed.length];
    ret += seed[Math.floor(seconds/=seed.length) % seed.length];

    for(var i = 0; i < 8; i++)
        ret += seed[Math.random()*seed.length|0];

    return ret;
}

Thoughts?

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