Module: RbNaCl::PasswordHash

Defined in:
lib/rbnacl/password_hash.rb,
lib/rbnacl/password_hash/scrypt.rb

Overview

Password hashing functions

These hash functions are designed specifically for the purposes of securely storing passwords in a way that they can be checked against a supplied password but an attacker who obtains a hash cannot easily reverse them back into the original password.

Unlike normal hash functions, which are intentionally designed to hash data as quickly as they can while remaining secure, password hashing functions are intentionally designed to be slow so they are hard for attackers to brute force.

All password hashing functions take a "salt" value which should be randomly generated on a per-password basis (using RbNaCl::Random, accept no subsitutes)

All of them also take a CPU work factor, which increases the amount of computation needed to produce the digest.

Defined Under Namespace

Classes: SCrypt

Class Method Summary collapse

Class Method Details

.scrypt(password, salt, opslimit, memlimit, digest_size = 64) ⇒ String

scrypt: the original sequential memory hard password hashing function. This is also the only password hashing function supported by libsodium, but that's okay, because it's pretty awesome.

Parameters:

  • password (String) —

    to be hashed

  • salt (String) —

    to make the digest unique

  • opslimit (Integer) —

    the CPU cost (e.g. 2**20)

  • memlimit (Integer) —

    the memory cost (e.g. 2**24)

  • digest_size (Integer) (defaults to: 64) —

    of the output

Returns:

  • (String) —

    The scrypt digest as raw bytes

Raises:

  • (CryptoError) —

    If calculating the digest fails for some reason.



35
36
37
 
# File 'lib/rbnacl/password_hash.rb', line 35

def self.scrypt(password, salt, opslimit, memlimit, digest_size = 64)
  SCrypt.new(opslimit, memlimit, digest_size).digest(password, salt)
end