sodium_crypto_pwhash_scryptsalsa208sha256
(PHP 7 >= 7.2.0, PHP 8)
sodium_crypto_pwhash_scryptsalsa208sha256 — Derives a key from a password, using scrypt
Description
int
$length,string
$password,string
$salt,int
$opslimit,int
$memlimit): string
This is the scrypt counterpart to sodium_crypto_pwhash().
A common reason to use this particular function is to derive the seeds for cryptographic keys from a password and salt, and then use these seeds to generate the actual keys needed for some purpose (e.g. sodium_crypto_sign_detached()).
Parameters
-
length -
The length of the password hash to generate, in bytes.
-
password -
The password to generate a hash for.
-
salt -
A salt to add to the password before hashing. The salt should be unpredictable, ideally generated from a good random number source such as random_bytes(), and have a length of at least
SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_SALTBYTESbytes. -
opslimit -
Represents a maximum amount of computations to perform. Raising this number will make the function require more CPU cycles to compute a key. There are some constants available to set the operations limit to appropriate values depending on intended use, in order of strength:
SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_INTERACTIVEandSODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_SENSITIVE. -
memlimit -
The maximum amount of RAM that the function will use, in bytes. There are constants to help you choose an appropriate value, in order of size:
SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_INTERACTIVEandSODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_SENSITIVE. Typically these should be paired with the matchingopslimitvalues.
Return Values
A string of bytes of the desired length.
