sodium_crypto_pwhash_scryptsalsa208sha256

sodium_crypto_pwhash_scryptsalsa208sha256

Derives a key from a password, using scrypt

string **sodium_crypto_pwhash_scryptsalsa208sha256** int $length string $password string $salt int $opslimit int $memlimit

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

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

passwordThe 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 , and have a length of at least bytes. random_bytes``SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_SALTBYTES

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: and . SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_INTERACTIVE``SODIUM_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: and . Typically these should be paired with the matching values. SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_INTERACTIVE``SODIUM_CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_SENSITIVE``opslimit

A string of bytes of the desired length.