----------------------------------------------------------------------------------
-- COPYRIGHT (c) 2016 ALL RIGHT RESERVED
--
-- COMPANY:					Ruhr-Universitaet Bochum, Chair for Embedded Security
-- AUTHOR:					Pascal Sasdrich
--
-- CREATE DATA:			17/11/2016
-- MODULE NAME:			KeyExpansion
--
--	REVISION:				1.00 - File created
--
-- LICENCE: 				Please look at licence.txt
-- USAGE INFORMATION:	Please look at readme.txt. If licence.txt or readme.txt
--								are missing or	if you have questions regarding the code
--								please contact Pascal Sasdrich (pascal.sasdrich@rub.de)
--								or Amir Moradi (amir.moradi@rub.de).
--
-- THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY 
-- KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
-- PARTICULAR PURPOSE.
----------------------------------------------------------------------------------



-- IMPORTS
----------------------------------------------------------------------------------
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;

USE WORK.SKINNYPKG.ALL;



-- ENTITY
----------------------------------------------------------------------------------
ENTITY KeyExpansion IS
	GENERIC (BS : BLOCK_SIZE := BLOCK_SIZE_128; TS : TWEAK_SIZE := TWEAK_SIZE_1N);
	PORT ( --CLK			: IN  STD_LOGIC;
			 -- CONTROL PORTS --------------------------------
			 --INIT			: IN	STD_LOGIC;
			 -- KEY PORTS ------------------------------------
          KEY			: IN  STD_LOGIC_VECTOR ((GET_TWEAK_SIZE(BS, TS) - 1) DOWNTO 0);
          ROUND_KEY	: OUT STD_LOGIC_VECTOR ((GET_TWEAK_SIZE(BS, TS) - 1) DOWNTO 0));
END KeyExpansion;



-- ARCHITECTURE : MIXED
----------------------------------------------------------------------------------
ARCHITECTURE Mixed OF KeyExpansion IS

	-- CONSTANTS ------------------------------------------------------------------
	CONSTANT N : INTEGER := GET_BLOCK_SIZE(BS);
	CONSTANT T : INTEGER := GET_TWEAK_SIZE(BS, TS);
	CONSTANT W : INTEGER := GET_WORD_SIZE(BS);
	
	-- SIGNALS --------------------------------------------------------------------
	SIGNAL PERMUTED_KEY, NEXT_KEY	: STD_LOGIC_VECTOR((T - 1) DOWNTO 0);

BEGIN

	-- TWEAKEY ARRAY PERMUTATIONS : TK1 -------------------------------------------
	TK1 : IF TS = TWEAK_SIZE_1N OR TS = TWEAK_SIZE_2N OR TS = TWEAK_SIZE_3N GENERATE 
		
		-- PERMUTATION -------------------------------------------------------------
		P1 : ENTITY work.Permutation
		GENERIC MAP (BS => BS) PORT MAP (
			KEY ((T - 1) DOWNTO (T - 1 * N)), 
			PERMUTED_KEY((T - 1) DOWNTO (T - 1 * N))
		); 
		
		-- NO LFSR -----------------------------------------------------------------
		NEXT_KEY((T - 1) DOWNTO (T - 1 * N)) <= PERMUTED_KEY((T - 1) DOWNTO (T - 1 * N));
		
	END GENERATE;
	-------------------------------------------------------------------------------
	
	
	-- KEY OUTPUT -----------------------------------------------------------------
	ROUND_KEY <= NEXT_KEY;
	-------------------------------------------------------------------------------
	
END Mixed;