sodium_crypto_pwhash_scryptsalsa208sha256

Derives a key from a password, using scrypt.

sodium_crypto_pwhash_scryptsalsa208sha256 Function synopsis

sodium_crypto_pwhash_scryptsalsa208sha256(
    int $length,
    string $password,
    string $salt,
    int $opslimit,
    int $memlimit
  ): string

Parameters

$length

Typeint

The length of the password hash to generate, in bytes.

$password

Typestring

The password to generate a hash for.

$salt

Typestring

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_SALTBYTES bytes.

$opslimit

Typeint

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_INTERACTIVE and SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_SENSITIVE.

$memlimit

Typeint

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_INTERACTIVE and SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_SENSITIVE. Typically these should be paired with the matching $opslimit values.

Return value

Typestring

A string of bytes of the desired length.