Generate a pseudo-random string of bytes

Descrição

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.

Parâmetros

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

Valor Retornado

Returns the generated string of bytes.

Erros/Exceções

openssl_random_pseudo_bytes() throws an Exception on failure.

Registro de Alterações

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

Exemplos

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;
}
?>

O exemplo acima produzirá algo semelhante 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)

Veja Também

random_bytes() - Obtém bytes aleatórios criptograficamente seguros
bin2hex() - Converte um dado binário em representação hexadecimal
crypt() - Hash unidirecional de string
random_int() - Obtém um número inteiro selecionado uniformemente e criptograficamente seguro