openssl_random_pseudo_bytes

(PHP 5 >= 5.3.0, PHP 7)

openssl_random_pseudo_bytesGenerate a pseudo-random string of bytes

Descrierea

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.

Parametri

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

Valorile întoarse

Returns the generated string of bytes on success, sau FALSE în cazul eșecului.

Exemple

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;
}
?>

Exemplul de mai sus va afișa ceva similar cu:

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)

A se vedea și

  • random_bytes() - Generates cryptographically secure pseudo-random bytes
  • bin2hex() - Convert binary data into hexadecimal representation
  • crypt() - One-way string hashing
  • mt_rand() - Generate a random value via the Mersenne Twister Random Number Generator
  • uniqid() - Generate a unique ID