Rails 5 - has_secure_password

has_secure_password(options = {})Link

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

The following validations are added automatically:

• Password must be present on creation
• Password length should be less than or equal to 72 characters
• Confirmation of password (using a password_confirmation attribute)

If password confirmation validation is not needed, simply leave out the value for password_confirmation (i.e. don't provide a form field for it). When this attribute has a nilvalue, the  validation will not be triggered.

For further customizability, it is possible to suppress the default validations by passing validations: false as an argument.

Add bcrypt (~> 3.1.7) to Gemfile to use has_secure_password:

gem 'bcrypt', '~> 3.1.7'

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')      # => false
User.find_by(name: 'david').try(:authenticate, 'mUc3m00RsqyRe') # => user

More at http://api.rubyonrails.org/classes/ActiveModel/SecurePassword/ClassMethods.html

https://rubyplus.com/episodes/311-Authentication-from-Scratch-in-Rails-5

https://rubyplus.com/articles/4171-Authentication-from-Scratch-in-Rails-5