Methods
A
H
Included Modules
Class Public methods
attributes_protected_by_default()

Source: show | on GitHub 

# File activemodel/lib/active_model/secure_password.rb, line 48
def self.attributes_protected_by_default
  super + ['password_digest']
end
Instance Public methods
has_secure_password()

Adds methods to set and authenticate against a BCrypt password. This mechanism requires you to have a password_digest attribute.

Validations for presence of password, confirmation of password (using a "password_confirmation" attribute) are automatically added. You can add more validations by hand if need be.

You need to add bcrypt-ruby (~> 3.0.0) to Gemfile to use #has_secure_password:

gem 'bcrypt-ruby', '~> 3.0.0'

Example using Active Record (which automatically includes ActiveModel::SecurePassword):

# Schema: User(name:string, password_digest:string)
class User < ActiveRecord::Base
  has_secure_password
end

user = User.new(:name => "david", :password => "", :password_confirmation => "nomatch")
user.save                                                      # => false, password required
user.password = "mUc3m00RsqyRe"
user.save                                                      # => false, confirmation doesn't match
user.password_confirmation = "mUc3m00RsqyRe"
user.save                                                      # => true
user.authenticate("notright")                                  # => false
user.authenticate("mUc3m00RsqyRe")                             # => user
User.find_by_name("david").try(:authenticate, "notright")      # => nil
User.find_by_name("david").try(:authenticate, "mUc3m00RsqyRe") # => user

Source: show | on GitHub 

# File activemodel/lib/active_model/secure_password.rb, line 34
def has_secure_password
  # Load bcrypt-ruby only when has_secure_password is used.
  # This is to avoid ActiveModel (and by extension the entire framework) being dependent on a binary library.
  gem 'bcrypt-ruby', '~> 3.0.0'
  require 'bcrypt'

  attr_reader :password

  validates_confirmation_of :password
  validates_presence_of     :password_digest

  include InstanceMethodsOnActivation

  if respond_to?(:attributes_protected_by_default)
    def self.attributes_protected_by_default
      super + ['password_digest']
    end
  end
end