从/dev/urandom转换随机值 [英] Convert random values from /dev/urandom

问题描述

如对mt_rand()的评论它的安全性很弱，我们应该改用/dev/urandom.我的问题是从urandom中我得到了一个二进制字符串.

As mentioned in the comments of mt_rand() it is weak in security and we should use /dev/urandom instead. My problem is that from urandom I get a binary string.

如何将该二进制字符串转换为0-9a-zA-Z?

How do I convert this binary string to 0-9a-zA-Z?

看起来像base_convert()在这里不起作用.

Looks like base_convert() does not work here.

推荐答案

仅记录完整功能:

function randomFromDev($len)
{
    $fp = @fopen('/dev/urandom','rb');
    $result = '';
    if ($fp !== FALSE) {
        $result .= @fread($fp, $len);
        @fclose($fp);
    }
    else
    {
        trigger_error('Can not open /dev/urandom.');
    }
    // convert from binary to string
    $result = base64_encode($result);
    // remove none url chars
    $result = strtr($result, '+/', '-_');
    // Remove = from the end
    $result = str_replace('=', ' ', $result);
    return $result;
}

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