(PHP 7, PHP 8)
random_bytes — Get cryptographically secure random bytes
$length): stringGenerates an arbitrary length string of cryptographic random bytes that are suitable for cryptographic use, such as when generating salts, keys or initialization vectors.
此函数使用的随机性来源如下：
注意: 虽然此函数是 PHP 7.0 添加到 PHP 中，但是从 PHP 5.2 到 PHP 5.6 都可以用 » 用户级实现。
length
The length of the random string that should be returned in bytes; must be 1 or greater.
A string containing the requested number of cryptographically secure random bytes.
length is less than 1,
a ValueError will be thrown.
| 版本 | 说明 |
|---|---|
| 8.2.0 | In case of a CSPRNG failure, this function will now throw a Random\RandomException. Previously a plain Exception was thrown. |
示例 #1 random_bytes() example
<?php
$bytes = random_bytes(5);
var_dump(bin2hex($bytes));
?>
以上例程的输出类似于：
string(10) "385e33f741"
<?php
function str_rand(int $length = 64){ // 64 = 32
$length = ($length < 4) ? 4 : $length;
return bin2hex(random_bytes(($length-($length%2))/2));
}
var_dump(str_rand());
// d6199909d0b5fdc22c9db625e4edf0d6da2b113b21878cde19e96f4afe69e714
?>
