OPENSSL_RANDOM_PSEUDO_BYTES(3) 1 OPENSSL_RANDOM_PSEUDO_BYTES(3)
openssl_random_pseudo_bytes - Generate a pseudo-random string of bytes
SYNOPSIS
string openssl_random_pseudo_bytes (int $length, [bool &$crypto_strong])
DESCRIPTION
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.
PARAMETERS
o $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.
o $crypto_strong
- If passed into the function, this will hold a boolean value that determines if the algorithm used was "cryptographically
strong", e.g., safe for usage with GPG, passwords, etc. TRUE if it did, otherwise FALSE
RETURN VALUES
Returns the generated string of bytes on success, or FALSE on failure.
EXAMPLES
Example #1
openssl_random_pseudo_bytes(3) example
<?php
for ($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: 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)
SEE ALSO
random_bytes(3), bin2hex(3), crypt(3), mt_rand(3), uniqid(3).
PHP Documentation Group OPENSSL_RANDOM_PSEUDO_BYTES(3)
