has_secure_password - 只有散列或加密？

Question

我不完全确定，当您在Rails模型中添加has_secure_password时，会涉及任何加密。我知道绝对有一个盐的散列，但有加密吗？ bcrypt可以使用河豚，但它被用在bcrypt-ruby（所有这一切的宝石）？

Answer 1

TL; DR：has_secure_password将使您在使用self.password=方法时使用Bcrypt的散列函数。

---

让我们来看看has_secure_password代码：

# 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 

我们可以看到，它不散列/加密任何东西。然而，我们注意到：

 include InstanceMethodsOnActivation 

如果我们去的InstanceMethodsOnActivation的文档，我们得到如下代码上：

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/哈希什么，但包括InstanceMethodsOnActivation模块。该模块定义了password=方法。这种方法的重要组成部分是：

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

现在让我们去看看BCrypt::Password.create的代码：

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 

在这种方法中，我们注意到一个特殊：

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

如此看来成为一个散列，这是合乎逻辑的（无论如何你都不想解密密码）。