(PHP 5 >= 5.5.0)
hash_pbkdf2 — Generate a PBKDF2 key derivation of a supplied password
$algo
, string $password
, string $salt
, int $iterations
[, int $length = 0
[, bool $raw_output = false
]] )
algo
Name of selected hashing algorithm (i.e. md5, sha256, haval160,4, etc..) See hash_algos() for a list of supported algorithms.
password
The password to use for the derivation.
salt
The salt to use for the derivation. This value should be generated randomly.
iterations
The number of internal iterations to perform for the derivation.
length
The length of the output string. If raw_output
is TRUE this corresponds to the byte-length of the derived key, if
raw_output is FALSE this corresponds to twice the
byte-length of the derived key (as every byte of the key is returned as
two hexits).
If 0 is passed, the entire output of the supplied algorithm is used.
raw_output
When set to TRUE, outputs raw binary data. FALSE outputs lowercase
hexits.
Returns a string containing the derived key as lowercase hexits unless
raw_output is set to TRUE in which case the raw
binary representation of the derived key is returned.
An E_WARNING will be raised if the algorithm is
unknown, the iterations parameter is less than or
equal to 0, the length is less
than 0 or the salt is too long
(greater than INT_MAX - 4).
Example #1 hash_pbkdf2() example, basic usage
<?php
$password = "password";
$iterations = 1000;
// Generate a random IV using mcrypt_create_iv(),
// openssl_random_pseudo_bytes() or another suitable source of randomness
$salt = mcrypt_create_iv(16, MCRYPT_DEV_URANDOM);
$hash = hash_pbkdf2("sha256", $password, $salt, $iterations, 20);
echo $hash;
?>
以上例程的输出类似于：
120fb6cffcf8b32c43e7
The PBKDF2 method can be used for hashing passwords for storage. However, it
should be noted that password_hash() or
crypt() with CRYPT_BLOWFISH are
better suited for password storage.