class Eth::Key::Decrypter

def derive_key(password)
  case kdf
  when "pbkdf2"
    @key = OpenSSL::PKCS5.pbkdf2_hmac(password, salt, iterations, key_length, digest)
  when "scrypt"
    @key = SCrypt::Engine.scrypt(password, salt, n, r, p, key_length)
  else
    raise DecrypterError, "Unsupported key derivation function: #{kdf}!"
  end
end