(PHP 5 >= 5.3.0, PHP 7, PHP 8)
openssl_random_pseudo_bytes — Generate a pseudo-random string of bytes
Generates a string of pseudo-random bytes, with the number of bytes
determined by the length parameter.
It also indicates if a cryptographically strong algorithm was used to produce the
pseudo-random bytes, and does this via the optional strong_result
parameter. It's rare for this to be false, but some systems may be broken or old.
length
The length of the desired string of bytes. Must be a positive integer less than or equal to 2147483647. PHP will
try to cast this parameter to a non-null integer to use it.
strong_result
If passed into the function, this will hold a bool value that determines
if the algorithm used was "cryptographically strong", e.g., safe for usage with GPG,
passwords, etc. true if it did, otherwise false
Returns the generated string of bytes.
openssl_random_pseudo_bytes() throws an Exception on failure.
| Version | Description |
|---|---|
| 8.0.0 |
strong_result is nullable now.
|
| 7.4.0 |
The function no longer returns false on failure, but throws an Exception instead.
|
Example #1 openssl_random_pseudo_bytes() example
<?php
for ($i = 1; $i <= 4; $i++) {
$bytes = openssl_random_pseudo_bytes($i, $cstrong);
$hex = bin2hex($bytes);
echo "Lengths: Bytes: $i and Hex: " . strlen($hex) . PHP_EOL;
var_dump($hex);
var_dump($cstrong);
echo PHP_EOL;
}
?>The above example will output something similar to:
Lengths: Bytes: 1 and Hex: 2 string(2) "42" bool(true) Lengths: Bytes: 2 and Hex: 4 string(4) "dc6e" bool(true) Lengths: Bytes: 3 and Hex: 6 string(6) "288591" bool(true) Lengths: Bytes: 4 and Hex: 8 string(8) "ab86d144" bool(true)