random_bytes
(PHP 7)
random_bytes — Generates cryptographically secure pseudo-random bytes
Описание
string random_bytes
( int
$length
)Generates an arbitrary length string of cryptographic random bytes that are suitable for cryptographic use, such as when generating salts, keys or initialization vectors.
The sources of randomness used for this function are as follows:
- On Windows, » CryptGenRandom() will always be used.
- On Linux, the » getrandom(2) syscall will be used if available.
- On other platforms, /dev/urandom will be used.
- If none of the aforementioned sources are available, then an Exception will be thrown.
Замечание: Although this function was added to PHP in PHP 7.0, a » userland implementation is available for PHP 5.2 to 5.6, inclusive.
Список параметров
-
length -
The length of the random string that should be returned in bytes.
Возвращаемые значения
Returns a string containing the requested number of cryptographically secure random bytes.
Ошибки
- If an appropriate source of randomness cannot be found, an Exception will be thrown.
- If invalid parameters are given, a TypeError will be thrown.
-
If an invalid
lengthof bytes is given, an Error will be thrown.
Примеры
Пример #1 random_bytes() example
<?php
$bytes = random_bytes(5);
var_dump(bin2hex($bytes));
?>
Результатом выполнения данного примера будет что-то подобное:
string(10) "385e33f741"
Смотрите также
- random_int() - Generates cryptographically secure pseudo-random integers
- openssl_random_pseudo_bytes() - Generate a pseudo-random string of bytes
- bin2hex() - Преобразует бинарные данные в шестнадцатеричное представление
Коментарии
<?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
?>