From b7b9f36c9b922d7bfdc200b07077f956fd2d8b9a Mon Sep 17 00:00:00 2001
From: tmeissner <programming@goodcleanfun.de>
Date: Thu, 9 Jul 2020 10:45:58 +0200
Subject: [PATCH] Add CBCMAC-AES VHDL design

---
 cbcmac_aes/rtl/vhdl/cbcmac_aes.vhd | 117 +++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 cbcmac_aes/rtl/vhdl/cbcmac_aes.vhd

diff --git a/cbcmac_aes/rtl/vhdl/cbcmac_aes.vhd b/cbcmac_aes/rtl/vhdl/cbcmac_aes.vhd
new file mode 100644
index 0000000..9399aff
--- /dev/null
+++ b/cbcmac_aes/rtl/vhdl/cbcmac_aes.vhd
@@ -0,0 +1,117 @@
+-- ======================================================================
+-- CBC-MAC-AES
+-- Copyright (C) 2020 Torsten Meissner
+-------------------------------------------------------------------------
+-- 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 2 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, write to the Free Software
+-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+-- ======================================================================
+
+
+library ieee;
+  use ieee.std_logic_1164.all;
+  use ieee.numeric_std.all;
+
+use work.aes_pkg.all;
+
+
+
+entity cbcmac_aes is
+  port (
+    reset_i     : in  std_logic;                   -- low active async reset
+    clk_i       : in  std_logic;                   -- clock
+    start_i     : in  std_logic;                   -- start cbc
+    key_i       : in  std_logic_vector(0 to 127);  -- key input
+    data_i      : in  std_logic_vector(0 to 127);  -- data input
+    valid_i     : in  std_logic;                   -- input key/data valid flag
+    accept_o    : out std_logic;                   -- input accept
+    data_o      : out std_logic_vector(0 tO 127);  -- data output
+    valid_o     : out std_logic;                   -- output data valid flag
+    accept_i    : in  std_logic                    -- output accept
+  );
+end entity cbcmac_aes;
+
+
+
+architecture rtl of cbcmac_aes is
+
+
+  -- CBCMAC must have fix IV for security reasons
+  constant C_IV : std_logic_vector(0 to 127) := (others => '0');
+
+  signal s_aes_datain    : std_logic_vector(0 to 127);
+  signal s_aes_dataout   : std_logic_vector(0 to 127);
+  signal s_aes_dataout_d : std_logic_vector(0 to 127);
+  signal s_aes_key       : std_logic_vector(0 to 127);
+  signal s_key           : std_logic_vector(0 to 127);
+  signal s_aes_accept    : std_logic;
+  signal s_aes_validout  : std_logic;
+
+
+begin
+
+
+  s_aes_datain <= C_IV xor data_i when start_i = '1' else
+                  s_aes_dataout_d xor data_i;
+
+  data_o <= s_aes_dataout;
+
+  s_aes_key <= key_i when start_i = '1' else s_key;
+
+  accept_o <= s_aes_accept;
+
+  valid_o <= s_aes_validout;
+
+
+  inputregister : process (clk_i, reset_i) is
+  begin
+    if (reset_i = '0') then
+      s_key <= (others => '0');
+    elsif (rising_edge(clk_i)) then
+      if (valid_i = '1' and s_aes_accept = '1' and start_i = '1') then
+        s_key <= key_i;
+      end if;
+    end if;
+  end process inputregister;
+
+
+  outputregister : process (clk_i, reset_i) is
+  begin
+    if (reset_i = '0') then
+      s_aes_dataout_d <= (others => '0');
+    elsif (rising_edge(clk_i)) then
+      if (s_aes_validout = '1') then
+        s_aes_dataout_d <= s_aes_dataout;
+      end if;
+    end if;
+  end process outputregister;
+
+
+  i_aes : aes_enc
+    generic map (
+      design_type => "ITER"
+    )
+    port map (
+      reset_i  => reset_i,
+      clk_i    => clk_i,
+      key_i    => s_aes_key,
+      data_i   => s_aes_datain,
+      valid_i  => valid_i,
+      accept_o => s_aes_accept,
+      data_o   => s_aes_dataout,
+      valid_o  => s_aes_validout,
+      accept_i => accept_i
+    );
+
+
+end architecture rtl;