(PHP 5 >= 5.5.0, PHP 7)
hash_pbkdf2 — Generate a PBKDF2 key derivation of a supplied password
hash_pbkdf2 ( string $algo , string $password , string $salt , int $iterations [, int $length = 0 [, bool $binary = false ]] ) : string
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 binary
is true
this corresponds to the byte-length of the derived key, if binary
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.
binary
When set to true
, outputs raw binary data. false
outputs lowercase hexits.
Returns a string containing the derived key as lowercase hexits unless binary
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
).
Version | Description |
---|---|
7.2.0 | Usage of non-cryptographic hash functions (adler32, crc32, crc32b, fnv132, fnv1a32, fnv164, fnv1a64, joaat) was disabled. |
Example #1 hash_pbkdf2() example, basic usage
<?php $password = "password"; $iterations = 1000; // Generate a random IV using openssl_random_pseudo_bytes() // random_bytes() or another suitable source of randomness $salt = openssl_random_pseudo_bytes(16); $hash = hash_pbkdf2("sha256", $password, $salt, $iterations, 20); echo $hash; ?>
The above example will output something similar to:
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.
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https://www.php.net/manual/en/function.hash-pbkdf2.php