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-- ====================================================================== |
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-- CBC-AES encryption/decryption |
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-- Copyright (C) 2021 Torsten Meissner |
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------------------------------------------------------------------------- |
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-- This program is free software; you can redistribute it and/or modify |
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-- it under the terms of the GNU General Public License as published by |
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-- the Free Software Foundation; either version 2 of the License, or |
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-- (at your option) any later version. |
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-- This program is distributed in the hope that it will be useful, |
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of |
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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-- GNU General Public License for more details. |
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-- You should have received a copy of the GNU General Public License |
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-- along with this program; if not, write to the Free Software |
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-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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-- ====================================================================== |
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library ieee; |
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use ieee.std_logic_1164.all; |
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use ieee.numeric_std.all; |
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use work.aes_pkg.all; |
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entity cbcaes is |
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port ( |
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reset_i : in std_logic; -- low active async reset |
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clk_i : in std_logic; -- clock |
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start_i : in std_logic; -- start cbc |
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mode_i : in std_logic; -- aes-modus: 0 = encrypt, 1 = decrypt |
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key_i : in std_logic_vector(0 to 127); -- key input |
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iv_i : in std_logic_vector(0 to 127); -- iv input |
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data_i : in std_logic_vector(0 to 127); -- data input |
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valid_i : in std_logic; -- input key/data valid flag |
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accept_o : out std_logic; -- ready to encrypt/decrypt |
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data_o : out std_logic_vector(0 to 127); -- data output |
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valid_o : out std_logic; -- output data valid flag |
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accept_i : in std_logic |
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); |
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end entity cbcaes; |
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architecture rtl of cbcaes is |
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signal s_mode : std_logic; |
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signal s_aes_mode : std_logic; |
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signal s_start : std_logic; |
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signal s_key : std_logic_vector(0 to 127); |
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signal s_aes_key : std_logic_vector(0 to 127); |
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signal s_iv : std_logic_vector(0 to 127); |
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signal s_datain : std_logic_vector(0 to 127); |
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signal s_datain_d : std_logic_vector(0 to 127); |
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signal s_aes_datain : std_logic_vector(0 to 127); |
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signal s_aes_dataout : std_logic_vector(0 to 127); |
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signal s_dataout : std_logic_vector(0 to 127); |
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begin |
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s_aes_datain <= iv_i xor data_i when mode_i = '0' and start_i = '1' else |
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s_dataout xor data_i when s_mode = '0' and start_i = '0' else |
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data_i; |
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data_o <= s_iv xor s_aes_dataout when s_mode = '1' and s_start = '1' else |
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s_datain_d xor s_aes_dataout when s_mode = '1' and s_start = '0' else |
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s_aes_dataout; |
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s_aes_key <= key_i when start_i = '1' else s_key; |
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s_aes_mode <= mode_i when start_i = '1' else s_mode; |
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inputregister : process (clk_i, reset_i) is |
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begin |
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if (reset_i = '0') then |
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s_mode <= '0'; |
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s_start <= '0'; |
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s_key <= (others => '0'); |
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s_iv <= (others => '0'); |
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s_datain <= (others => '0'); |
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s_datain_d <= (others => '0'); |
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elsif (rising_edge(clk_i)) then |
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if (valid_i = '1' and accept_o = '1') then |
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s_start <= start_i; |
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s_datain <= data_i; |
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s_datain_d <= s_datain; |
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if (start_i = '1') then |
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s_mode <= mode_i; |
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s_key <= key_i; |
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s_iv <= iv_i; |
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end if; |
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end if; |
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end if; |
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end process inputregister; |
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outputregister : process (clk_i, reset_i) is |
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begin |
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if (reset_i = '0') then |
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s_dataout <= (others => '0'); |
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elsif (rising_edge(clk_i)) then |
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if (valid_o = '1' and accept_i = '1') then |
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s_dataout <= s_aes_dataout; |
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end if; |
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end if; |
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end process outputregister; |
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i_aes : entity work.aes |
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generic map ( |
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design_type => "ITER" |
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) |
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port map ( |
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reset_i => reset_i, |
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clk_i => clk_i, |
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mode_i => s_aes_mode, |
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key_i => s_aes_key, |
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data_i => s_aes_datain, |
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valid_i => valid_i, |
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accept_o => accept_o, |
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data_o => s_aes_dataout, |
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valid_o => valid_o, |
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accept_i => accept_i |
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); |
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end architecture rtl; |