Use SCrypt for passphrase encryption

Gemfile

@@ -9,6 +9,8 @@ gem 'american_date'
 gem 'browserify-rails'
 gem 'coffee-rails', '~> 4.1.0'
 gem 'devise', '~> 4.1'
+gem 'devise-encryptable'
+gem 'devise-scrypt'
 gem 'devise_zxcvbn'
 gem 'dotiw'
 gem 'figaro'

Gemfile.lock

@@ -184,6 +184,12 @@ GEM
       railties (>= 4.1.0, < 5.1)
       responders
       warden (~> 1.2.3)
+    devise-encryptable (0.2.0)
+      devise (>= 2.1.0)
+    devise-scrypt (1.0.0)
+      devise (>= 2.1.0)
+      devise-encryptable (>= 0.1.1)
+      scrypt (>= 1.1.0)
     devise_zxcvbn (2.1.2)
       devise
       zxcvbn-js (~> 4.2.0)
@@ -215,6 +221,9 @@ GEM
     faker (1.6.6)
       i18n (~> 0.5)
     ffi (1.9.14)
+    ffi-compiler (1.0.1)
+      ffi (>= 1.0.0)
+      rake
     figaro (1.1.1)
       thor (~> 0.14)
     formatador (0.2.5)
@@ -464,6 +473,9 @@ GEM
       nokogiri (>= 1.4.0)
       nori (~> 2.4)
       wasabi (~> 3.4)
+    scrypt (3.0.3)
+      ffi-compiler (>= 1.0.0)
+      rake
     secure_headers (3.4.0)
       useragent
     shellany (0.0.1)
@@ -619,6 +631,8 @@ DEPENDENCIES
   database_cleaner
   derailed
   devise (~> 4.1)
+  devise-encryptable
+  devise-scrypt
   devise_zxcvbn
   dotiw
   email_spec

app/forms/recovery_code_form.rb

@@ -17,7 +17,7 @@ def submit
   attr_reader :user, :code, :success
 
   def valid_recovery_code?
-    Devise::Encryptor.compare(User, user.recovery_code, code)
+    RecoveryCodeGenerator.new(user).valid?(code)
   end
 
   def result

app/services/recovery_code_generator.rb

@@ -10,12 +10,20 @@ def create
     raw_recovery_code
   end
 
+  def valid?(raw_code)
+    SCrypt::Password.new(user.recovery_code) == peppered_code(raw_code)
+  end
+
   private
 
   attr_reader :length, :user
 
+  def peppered_code(raw_code = raw_recovery_code)
+    "#{raw_code}#{User.pepper}"
+  end
+
   def hashed_code
-    Devise::Encryptor.digest(User, raw_recovery_code)
+    SCrypt::Password.create(peppered_code)
   end
 
   def raw_recovery_code

config/initializers/devise.rb

@@ -17,7 +17,23 @@
   config.sign_in_after_reset_password = false
   config.sign_out_via = :delete
   config.skip_session_storage = [:http_auth]
-  config.stretches = Rails.env.test? ? 1 : 12
+
+  # The scrypt encryptor ignores stretches but we keep for compatability.
+  # We can set the scrypt config directly.
+  # see https://github.com/pbhogan/scrypt
+  # and https://github.com/capita/devise-scrypt
+  # We set the test config much lower just to speed up tests.
+  config.encryptor = :scrypt
+  if Rails.env.test?
+    SCrypt::Engine::DEFAULTS[:key_len] = 16
+    SCrypt::Engine::DEFAULTS[:salt_size] = 8
+    config.stretches = 1
+  else
+    SCrypt::Engine::DEFAULTS[:key_len] = 64
+    SCrypt::Engine::DEFAULTS[:salt_size] = 32
+    config.stretches = 12
+  end
+
   config.strip_whitespace_keys = [:email]
   config.timeout_in = Figaro.env.session_timeout_in.to_i.minutes
 

spec/factories/users.rb

@@ -21,7 +21,7 @@
 
     trait :signed_up do
       with_phone
-      recovery_code '$2a$10$vOkU3l3j0aYgWbXVdwJA5.FICxwydpvPrzBuzjFZUXDnPeXkMHeLe'
+      recovery_code SCrypt::Password.create('recovery' + User.pepper)
     end
 
     trait :unconfirmed do

spec/services/recovery_code_generator_spec.rb

@@ -35,4 +35,16 @@
       expect(generator.create).to match(/\A[a-zA-Z0-9]{14}\z/)
     end
   end
+
+  describe '#valid?' do
+    it 'validates the raw recovery code against what is stored for the User' do
+      user = create(:user)
+      generator = RecoveryCodeGenerator.new(user)
+      raw_code = generator.create
+
+      generator2 = RecoveryCodeGenerator.new(user)
+
+      expect(generator2.valid?(raw_code)).to eq true
+    end
+  end
 end