s2_box.vhd

fpga3des加密非常有用 希望大家喜

---------------------------------------------------------------------
--				(c) Copyright 2006, CoreTex Systems, LLC					 --
--		                   www.coretexsys.com                        --    
--                                                            		 --
--		This source file may be used and distributed without         --
--		restriction provided that this copyright statement is not    --
--		removed from the file and that any derivative work contains  --
--		the original copyright notice and the associated disclaimer. --
--                                                            		 --
--		    THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY      --
--		EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED    --
--		TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS    --
--		FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR       --
--		OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,          --
--		INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES     --
--		(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE    --
--		GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR         --
--		BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF   --
--		LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT   --
--		(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT   --
--		OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE          --
--		POSSIBILITY OF SUCH DAMAGE.                                  --
--																						 --
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----------------------------------------------------------------------

-- Poject structure: 

--  |- tdes_top.vhd
--  |
--    |- des_cipher_top.vhd
--    |- des_top.vhd
--      |- block_top.vhd
--        |- add_key.vhd
--        |
--        |- add_left.vhd
--        |
--				|- e_expansion_function.vhd
--				|
--				|- p_box.vhd
--				|
--				|- s_box.vhd
--            |- s1_box.vhd
--            |- s2_box.vhd
--            |- s3_box.vhd
--            |- s4_box.vhd
--            |- s5_box.vhd
--            |- s6_box.vhd
--            |- s7_box.vhd
--            |- s8_box.vhd
--    |- key_schedule.vhd

----------------------------------------------------------------------

---------------------------------------------------------------------------------------------------
--
-- Title       : s2_box
-- Company     : CoreTex Systems, LLC
--
---------------------------------------------------------------------------------------------------

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY s2_box IS
	port (
	A: IN std_logic_VECTOR(5 downto 0);
	SPO: OUT std_logic_VECTOR(3 downto 0));
END s2_box;

architecture Behavioral of s2_box is

begin

SPO 	<= "1111" when A = x"0" else
			"0011" when A = x"1" else
			"0001" when A = x"2" else
			"1101" when A = x"3" else
			"1000" when A = x"4" else
			"0100" when A = x"5" else
			"1110" when A = x"6" else
			"0111" when A = x"7" else
			"0110" when A = x"8" else
			"1111" when A = x"9" else
			"1011" when A = x"A" else
			"0010" when A = x"B" else
			"0011" when A = x"C" else
			"1000" when A = x"D" else
			"0100" when A = x"E" else
			"1110" when A = x"F" else
			"1001" when A = x"10" else
			"1100" when A = x"11" else
			"0111" when A = x"12" else
			"0000" when A = x"13" else
			"0010" when A = x"14" else
			"0001" when A = x"15" else
			"1101" when A = x"16" else
			"1010" when A = x"17" else
			"1100" when A = x"18" else
			"0110" when A = x"19" else
			"0000" when A = x"1A" else
			"1001" when A = x"1B" else
			"0101" when A = x"1C" else
			"1011" when A = x"1D" else
			"1010" when A = x"1E" else
			"0101" when A = x"1F" else
			"0000" when A = x"20" else
			"1101" when A = x"21" else
			"1110" when A = x"22" else
			"1000" when A = x"23" else
			"0111" when A = x"24" else
			"1010" when A = x"25" else
			"1011" when A = x"26" else
			"0001" when A = x"27" else
			"1010" when A = x"28" else
			"0011" when A = x"29" else
			"0100" when A = x"2A" else
			"1111" when A = x"2B" else
			"1101" when A = x"2C" else
			"0100" when A = x"2D" else
			"0001" when A = x"2E" else
			"0010" when A = x"2F" else
			"0101" when A = x"30" else
			"1011" when A = x"31" else
			"1000" when A = x"32" else
			"0110" when A = x"33" else
			"1100" when A = x"34" else
			"0111" when A = x"35" else
			"0110" when A = x"36" else
			"1100" when A = x"37" else
			"1001" when A = x"38" else
			"0000" when A = x"39" else
			"0011" when A = x"3A" else
			"0101" when A = x"3B" else
			"0010" when A = x"3C" else
			"1110" when A = x"3D" else
			"1111" when A = x"3E" else
			"1001" when A = x"3F" else
			"1001";

END Behavioral;