如何保护Rails模型属性？

class User< ApplicationRecord
  validates :email, presence: true, uniqueness: true
  validates :age, numericality: { greater_than_or_equal_to: 18 }
end

class UsersController< ApplicationController
  before_action :authenticate_user!
  before_action :set_user, only: [:show, :edit, :update, :destroy]
  before_action :check_permission, only: [:edit, :update, :destroy]

  def show
  end

  def edit
  end

  def update
    if @user.update(user_params)
      redirect_to @user, notice: 'User was successfully updated.'
    else
      render :edit
    end
  end

  def destroy
    @user.destroy
    redirect_to users_url, notice: 'User was successfully destroyed.'
  end

  private

  def set_user
    @user = User.find(params[:id])
  end

  def check_permission
    unless current_user.admin? || current_user == @user
      redirect_to root_path, alert: 'You are not authorized to perform this action.'
    end
  end

  def user_params
    params.require(:user).permit(:email, :age)
  end
end

gem 'attr_encrypted'

class User< ApplicationRecord
  attr_encrypted :email, key: 'a secret key'
end