openssl_random_pseudo_bytes

(PHP 5 >= 5.3.0, PHP 7)

openssl_random_pseudo_bytesGenerate a pseudo-random string of bytes

Beschreibung

openssl_random_pseudo_bytes ( int $length [, bool &$crypto_strong ] ) : 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 crypto_strong parameter. It's rare for this to be FALSE, but some systems may be broken or old.

Parameter-Liste

length

The length of the desired string of bytes. Must be a positive integer. PHP will try to cast this parameter to a non-null integer to use it.

crypto_strong

If passed into the function, this will hold a boolean 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

Rückgabewerte

Returns the generated string of bytes on success, Im Fehlerfall wird FALSE zurückgegeben..

Beispiele

Beispiel #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;
}
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

Lengths: Bytes: -1 and Hex: 0
string(0) ""
NULL

Lengths: Bytes: 0 and Hex: 0
string(0) ""
NULL

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)

Siehe auch

  • random_bytes() - Generates cryptographically secure pseudo-random bytes
  • bin2hex() - Wandelt Binär-Daten in ihre hexadezimale Entsprechung um
  • crypt() - Einweg-String-Hashing
  • mt_rand() - Erzeugt eine Zufallszahl nach dem Mersenne Twister Verfahren
  • uniqid() - Erzeugt eine eindeutige ID