has_secure_password - 只有散列或加密？

Question

我不完全確定，當您在Rails模型中添加has_secure_password時，會涉及任何加密。我知道絕對有一個鹽的散列，但有加密嗎？ bcrypt可以使用河豚，但它被用在bcrypt-ruby（所有這一切的寶石）？

Answer 1

TL; DR：has_secure_password將使您在使用self.password=方法時使用Bcrypt的散列函數。

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讓我們來看看has_secure_password代碼：

# File activemodel/lib/active_model/secure_password.rb, line 53 
    def has_secure_password(options = {}) 
     # Load bcrypt gem only when has_secure_password is used. 
     # This is to avoid ActiveModel (and by extension the entire framework) 
     # being dependent on a binary library. 
     begin 
     require "bcrypt" 
     rescue LoadError 
     $stderr.puts "You don't have bcrypt installed in your application. Please add it to your Gemfile and run bundle install" 
     raise 
     end 

     include InstanceMethodsOnActivation 

     if options.fetch(:validations, true) 
     include ActiveModel::Validations 

     # This ensures the model has a password by checking whether the password_digest 
     # is present, so that this works with both new and existing records. However, 
     # when there is an error, the message is added to the password attribute instead 
     # so that the error message will make sense to the end-user. 
     validate do |record| 
      record.errors.add(:password, :blank) unless record.password_digest.present? 
     end 

     validates_length_of :password, maximum: ActiveModel::SecurePassword::MAX_PASSWORD_LENGTH_ALLOWED 
     validates_confirmation_of :password, allow_blank: true 
     end 
    end 

我們可以看到，它不散列/加密任何東西。然而，我們注意到：

 include InstanceMethodsOnActivation 

如果我們去的InstanceMethodsOnActivation的文檔，我們得到如下代碼上：

def password=(unencrypted_password) 
    if unencrypted_password.nil? 
    self.password_digest = nil 
    elsif !unencrypted_password.empty? 
    @password = unencrypted_password 
    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST : BCrypt::Engine.cost 
    self.password_digest = BCrypt::Password.create(unencrypted_password, cost: cost) 
    end 
end 

因此，has_secure_password不加密/哈希什麼，但包括InstanceMethodsOnActivation模塊。該模塊定義了password=方法。這種方法的重要組成部分是：

self.password_digest = BCrypt::Password.create(unencrypted_password, cost: cost) 

現在讓我們去看看BCrypt::Password.create的代碼：

def create(secret, options = {}) 
    cost = options[:cost] || BCrypt::Engine.cost 
    raise ArgumentError if cost > 31 
    Password.new(BCrypt::Engine.hash_secret(secret, BCrypt::Engine.generate_salt(cost))) 
    end 

    def valid_hash?(h) 
    h =~ /^\$[0-9a-z]{2}\$[0-9]{2}\$[A-Za-z0-9\.\/]{53}$/ 
    end 
end 

在這種方法中，我們注意到一個特殊：

Password.new(BCrypt::Engine.hash_secret(secret, BCrypt::Engine.generate_salt(cost))) 

如此看來成爲一個散列，這是合乎邏輯的（無論如何你都不想解密密碼）。