openssl_random_pseudo_bytes

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

openssl_random_pseudo_bytesGenerate a pseudo-random string of bytes

Descrizione

openssl_random_pseudo_bytes(int $length, bool &$strong_result = null): string

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.

Elenco dei parametri

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

Valori restituiti

Returns the generated string of bytes.

Errori/Eccezioni

openssl_random_pseudo_bytes() throws an Exception on failure.

Log delle modifiche

Versione Descrizione
8.0.0 strong_result is nullable now.
7.4.0 The function no longer returns false on failure, but throws an Exception instead.

Esempi

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;
}
?>

Il precedente esempio visualizzerà qualcosa simile a:

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)

Vedere anche:

  • random_bytes() - Get cryptographically secure random bytes
  • bin2hex() - Converte i dati binari nella rappresentazione esadecimale
  • crypt() - Criptazione di una stringa a senso unico (hashing)
  • random_int() - Get a cryptographically secure, uniformly selected integer