Subversion Repositories deslxcore

-- Copyright (c) 2013 Antonio de la Piedra

-- This program is free software: you can redistribute it and/or modify

-- it under the terms of the GNU General Public License as published by

-- the Free Software Foundation, either version 3 of the License, or

-- (at your option) any later version.

-- This program 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 General Public License for more details.

-- You should have received a copy of the GNU General Public License

-- along with this program.  If not, see <http://www.gnu.org/licenses/>.

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

entity des_loop is

        port(clk :  in std_logic;

                  rst : in std_logic;

                  mode : in std_logic; -- 0 encrypt, 1 decrypt

                  key_in : in std_logic_vector(55 downto 0);

                  key_pre_w_in : in std_logic_vector(63 downto 0);

                  key_pos_w_in : in std_logic_vector(63 downto 0);

                  blk_in : in std_logic_vector(63 downto 0);

                  blk_out : out std_logic_vector(63 downto 0));

end des_loop;

architecture Behavioral of des_loop is

        signal after_ip_s : std_logic_vector(63 downto 0);

        signal after_ip_minus_one_s : std_logic_vector(63 downto 0);

        signal after_f_s : std_logic_vector(31 downto 0);

        signal final_s : std_logic_vector(63 downto 0);

        component des_round is

                port(clk : in std_logic;

                          l_0 : in std_logic_vector(31 downto 0);

                     r_0 : in std_logic_vector(31 downto 0);

                     k_i : in std_logic_vector(47 downto 0);

                     l_1 : out std_logic_vector(31 downto 0);

                     r_1 : out std_logic_vector(31 downto 0));

        end component;

        component key_schedule is

                port(clk : in std_logic;

                          rst : in std_logic;

                     mode : in std_logic; -- 0 encrypt, 1 decrypt

                key : in std_logic_vector(55 downto 0);

                     key_out : out std_logic_vector(47 downto 0));

        end component;

        signal key_s : std_logic_vector(47 downto 0);

        signal l_0_s : std_logic_vector(31 downto 0);

        signal l_1_s : std_logic_vector(31 downto 0);

        signal r_0_s : std_logic_vector(31 downto 0);

        signal r_1_s : std_logic_vector(31 downto 0);

        signal rst_s : std_logic;

        signal blk_in_s  : std_logic_vector(63 downto 0);

        signal blk_out_s : std_logic_vector(63 downto 0);

begin

        pr_rst_delay : process(clk, rst)

        begin

                if rising_edge(clk) then

                        rst_s <= rst;

                end if;

        end process;

        blk_in_s <= (blk_in xor key_pre_w_in) when mode = '0' else (blk_in xor key_pos_w_in);

        pr_seq: process(clk, rst_s, blk_in)

        begin

                if rst_s = '1' then

                        l_0_s <= blk_in_s(63 downto 32);

                        r_0_s <= blk_in_s(31 downto 0);

                elsif rising_edge(clk) then

                        l_0_s <= l_1_s;

                        r_0_s <= r_1_s;

                end if;

        end process;

        DES_ROUND_0 :  des_round port map (clk, l_0_s, r_0_s, key_s, l_1_s, r_1_s);

        blk_out_s <= r_1_s & l_1_s;

        blk_out <= (blk_out_s xor key_pre_w_in) when mode = '1' else (blk_out_s xor key_pos_w_in);

        KEY_SCHEDULE_0 : key_schedule port map (clk, rst, mode, key_in, key_s);

end Behavioral;