# -*- encoding: utf-8 -*-
#
#--
# This file is part of HexaPDF.
#
# HexaPDF - A Versatile PDF Creation and Manipulation Library For Ruby
# Copyright (C) 2014-2017 Thomas Leitner
#
# HexaPDF is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License version 3 as
# published by the Free Software Foundation with the addition of the
# following permission added to Section 15 as permitted in Section 7(a):
# FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
# THOMAS LEITNER, THOMAS LEITNER DISCLAIMS THE WARRANTY OF NON
# INFRINGEMENT OF THIRD PARTY RIGHTS.
#
# HexaPDF is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
# License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with HexaPDF. If not, see <http://www.gnu.org/licenses/>.
#
# The interactive user interfaces in modified source and object code
# versions of HexaPDF must display Appropriate Legal Notices, as required
# under Section 5 of the GNU Affero General Public License version 3.
#
# In accordance with Section 7(b) of the GNU Affero General Public
# License, a covered work must retain the producer line in every PDF that
# is created or manipulated using HexaPDF.
#++

require 'openssl'
require 'hexapdf/encryption/arc4'

module HexaPDF
  module Encryption

    # Implementation of the general encryption algorithm ARC4 using OpenSSL as backend.
    #
    # See: PDF1.7 s7.6.2
    class FastARC4

      prepend ARC4

      # Creates a new FastARC4 object using the given encryption key.
      def initialize(key)
        @cipher = OpenSSL::Cipher::RC4.new
        @cipher.key_len = key.length
        @cipher.key = key
      end

      # Processes the given data.
      #
      # Since this is a symmetric algorithm, the same method can be used for encryption and
      # decryption.
      def process(data)
        @cipher.update(data)
      end
      alias :decrypt :process
      alias :encrypt :process

    end

  end
end