Class: Strongbox::Lock

Inherits:
Object
  • Object
show all
Defined in:
lib/strongbox/lock.rb

Overview

The Lock class encrypts and decrypts the protected attribute. It automatically encrypts the data when set and decrypts it when the private key password is provided.

Instance Method Summary collapse

Constructor Details

#initialize(name, instance, options = {}) ⇒ Lock

Returns a new instance of Lock.



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# File 'lib/strongbox/lock.rb', line 7

def initialize name, instance, options = {}
  @name              = name
  @instance          = instance
  
  @size = nil
  
  options = Strongbox.options.merge(options)
  
  @is_empty = true if @instance[@name].blank?
  
  @base64 = options[:base64]
  @public_key = options[:public_key] || options[:key_pair]
  @private_key = options[:private_key] || options[:key_pair]
  @padding = options[:padding]
  @symmetric = options[:symmetric]
  @symmetric_cipher = options[:symmetric_cipher]
  @symmetric_key = options[:symmetric_key] || "#{name}_key"
  @symmetric_iv = options[:symmetric_iv] || "#{name}_iv"
  @key_proc = options[:key_proc]
  @encrypt_iv = options[:encrypt_iv]
  if @symmetric == :only
    if @encrypt_iv
      raise ArgumentError, ":encrypt_iv should be set to false for :symmetric => :only encryption, since encrypting the iv requires a pubkey"
    end
    if @public_key
      raise ArgumentError, ":public_key, :private_key and :key_pair are not used with :symmetric => :only"
    end
    unless @key_proc
      raise ArgumentError, ":key_proc option is required.  This option specifies a proc or a symbol of a method on the instance, which will return a key used for the symmetric cypher."
    end
  else
    if @key_proc
      raise ArgumentError, ":key_proc is valid only when :symmetric => :only is specified, or when using encrypt_with_symmetric_key()"
    end
  end
end

Instance Method Details

#blank? ⇒ Boolean

Needed for validations

Returns:

  • (Boolean) 


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# File 'lib/strongbox/lock.rb', line 172

def blank?
  @instance[@name].blank?
end

#decrypt(password = nil) ⇒ Object

Given the private key password decrypts the attribute. Will raise OpenSSL::PKey::RSAError if the password is wrong.



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# File 'lib/strongbox/lock.rb', line 110

def decrypt password = nil
  return "" if @is_empty
  # Given a private key and a nil password OpenSSL::PKey::RSA.new() will
  # *prompt* for a password, we default to an empty string to avoid that.
  ciphertext = @instance[@name]
  return nil if ciphertext.nil?
  return "" if ciphertext.empty?
  
  return "*encrypted*" if password.nil? and ! @key_proc
  unless @private_key or @symmetric == :only
    raise StrongboxError.new("#{@instance.class} model does not have private key_file")
  end
  
  if ciphertext
    ciphertext = Base64.decode64(ciphertext) if @base64
    private_key = get_rsa_key(@private_key,password)
    
    if @symmetric == :always || @symmetric == :only
      symmetric_key = case @key_proc
      when Proc
        @key_proc.call( @instance )
      when Symbol
        @instance.send( @key_proc )
      else
        @instance[@symmetric_key]
      end
      symmetric_iv = @instance[@symmetric_iv]
      
      if @base64
        if @symmetric == :always
          symmetric_key = Base64.decode64(symmetric_key)
        end
        symmetric_iv = Base64.decode64(symmetric_iv)
      end
      cipher = OpenSSL::Cipher::Cipher.new(@symmetric_cipher)
      cipher.decrypt
      cipher.key = if @symmetric == :only
        symmetric_key
      else
        private_key.private_decrypt(symmetric_key,@padding)
      end
      if @encrypt_iv
        cipher.iv = private_key.private_decrypt(symmetric_iv,@padding)
      else
        cipher.iv = symmetric_iv
      end
      
      plaintext = cipher.update(ciphertext)
      plaintext << cipher.final
    else
      plaintext = private_key.private_decrypt(ciphertext,@padding)
    end
  else
    nil
  end
end

#encrypt(plaintext) ⇒ Object 



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# File 'lib/strongbox/lock.rb', line 44

def encrypt plaintext
  
  unless @public_key or @symmetric == :only
    raise StrongboxError.new("#{@instance.class} model does not have public key_file")
  end
  if !plaintext.blank?
    @is_empty = false
    @size = plaintext.size # For validations
    # Using a blank password in OpenSSL::PKey::RSA.new prevents reading
    # the private key if the file is a key pair
    public_key = get_rsa_key(@public_key,"")
    if @symmetric == :always or @symmetric == :only
      cipher = OpenSSL::Cipher::Cipher.new(@symmetric_cipher)
      cipher.encrypt
      
      cipher.key = symmetric_key = case @key_proc
      when Proc
        @key_proc.call( @instance )
      when Symbol
        @instance.send( @key_proc )
      else
        cipher.random_key
      end
      cipher.iv = symmetric_iv = cipher.random_iv

      ciphertext = cipher.update(plaintext)
      ciphertext << cipher.final
      unless @symmetric == :only
        encrypted_key = public_key.public_encrypt(symmetric_key,@padding)
      end
      if @encrypt_iv
        encrypted_iv = public_key.public_encrypt(symmetric_iv,@padding)
      end
      if @base64
        unless @symmetric == :only
          encrypted_key = Base64.encode64(encrypted_key)
        end
        if @encrypt_iv
          encrypted_iv = Base64.encode64(encrypted_iv)
        else
          symmetric_iv = Base64.encode64(symmetric_iv)
        end
      end
      unless @symmetric == :only
        @instance[@symmetric_key] = encrypted_key
      end
      if @encrypt_iv
        @instance[@symmetric_iv] = encrypted_iv
      else
        @instance[@symmetric_iv] = symmetric_iv
      end
    else
      ciphertext = public_key.public_encrypt(plaintext,@padding)
    end
    ciphertext =  Base64.encode64(ciphertext) if @base64
    @instance[@name] = ciphertext
  else
    @size = 0
    @instance[@name] = ""
    @is_empty = true
  end
end

#nil? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/strongbox/lock.rb', line 176

def nil?
  @instance[@name].nil?
end

#size ⇒ Object 



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# File 'lib/strongbox/lock.rb', line 180

def size
  @size
end

#to_s ⇒ Object 



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# File 'lib/strongbox/lock.rb', line 167

def to_s
  decrypt
end