在PHP中使用OpenSSL随机获取负数 [英] Get Negative Numbers With OpenSSL Random In PHP

问题描述

我正在弄乱一些代码，以使用PHP创建强大的伪随机数生成器.到目前为止，我有以下内容.

I'm messing around with some code to make a strong pseudo-random number generator using PHP. So far, I have the following.

function strongRand($bytes, $min, $max)
{
    if(function_exists('openssl_random_pseudo_bytes'))
    {
        $strong = true;
        $n = 0;

        do{
            $n = hexdec(bin2hex(openssl_random_pseudo_bytes($bytes, $strong)));
        }
        while($n < $min || $n > $max);

        return $n;
    }
    else{
        return mt_rand($min, $max);
    }
}

这对我来说几乎是完美的-除了我用openssl_random_pseudo_bytes生成的所有数字都是正数.理想情况下，我想生成从-x到+ y的数字.我曾考虑过可能再添加一个PRNG调用来确定数字是正数还是负数，但是我不确定这是否是最好的方法.

This is almost perfect for me—except that all of the numbers that I generate with openssl_random_pseudo_bytes are positive. Ideally, I'd like to generate numbers from -x to +y. I have thought about maybe adding a another PRNG call to decide if a number should be positive or negative, but I'm not sure if that's the best way to go.

推荐答案

您可以简单地添加另一个随机函数，我们将使用rand(0,1)它将生成0或1，如果是1 $status = 1则将生成0或.当我们返回值时，我们将乘以$ status:

You could simply add another random function, we'll use rand(0,1) this will generate 0 or 1, if it's 1 $status = 1 if it's 0 $status = -1. When we return the value we do multiplication by $status:

function strongRand($bytes, $min, $max)
{
    $status = mt_rand(0,1) === 1 ? 1:-1;

    if(function_exists('openssl_random_pseudo_bytes'))
    {
        $strong = true;
        $n = 0;

        do{
            $n = hexdec(bin2hex(openssl_random_pseudo_bytes($bytes, $strong)));
        }
        while($n < $min || $n > $max);

        return $n * $status;
    }
    else{
        return mt_rand($min, $max) * $status;
    }
}

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