cryptocores/des/rtl/des.vhd

-- ======================================================================
-- DES encryption/decryption
-- algorithm according to FIPS 46-3 specification
-- Copyright (C) 2007 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
-- ======================================================================


-- Revision 1.0  2007/02/04
-- Initial release
-- Revision 1.1  2007/02/05
-- Corrected error in use of mode register for key calculation


LIBRARY ieee;
USE ieee.std_logic_1164.all;
USE ieee.numeric_std.ALL;
USE work.des_pkg.ALL;


ENTITY des IS
  PORT (
    clk_i       : IN  std_logic;                  -- clock
    mode_i      : IN  std_logic;                  -- des-modus: 0 = encrypt, 1 = decrypt
    key_i       : IN  std_logic_vector(0 TO 63);  -- key input
    data_i      : IN  std_logic_vector(0 TO 63);  -- data input
    valid_i     : IN  std_logic;                  -- input key/data valid flag
    data_o      : OUT std_logic_vector(0 TO 63);  -- data output
    valid_o     : OUT std_logic                   -- output data valid flag
  );
END ENTITY des;


ARCHITECTURE rtl OF des IS

BEGIN

  crypt : PROCESS ( clk_i ) IS
    -- variables for key calculation
    VARIABLE c0  : std_logic_vector(0 TO 27);
    VARIABLE c1  : std_logic_vector(0 TO 27);
    VARIABLE c2  : std_logic_vector(0 TO 27);
    VARIABLE c3  : std_logic_vector(0 TO 27);
    VARIABLE c4  : std_logic_vector(0 TO 27);
    VARIABLE c5  : std_logic_vector(0 TO 27);
    VARIABLE c6  : std_logic_vector(0 TO 27);
    VARIABLE c7  : std_logic_vector(0 TO 27);
    VARIABLE c8  : std_logic_vector(0 TO 27);
    VARIABLE c9  : std_logic_vector(0 TO 27);
    VARIABLE c10 : std_logic_vector(0 TO 27);
    VARIABLE c11 : std_logic_vector(0 TO 27);
    VARIABLE c12 : std_logic_vector(0 TO 27);
    VARIABLE c13 : std_logic_vector(0 TO 27);
    VARIABLE c14 : std_logic_vector(0 TO 27);
    VARIABLE c15 : std_logic_vector(0 TO 27);
    VARIABLE c16 : std_logic_vector(0 TO 27);
    VARIABLE d0  : std_logic_vector(0 TO 27);
    VARIABLE d1  : std_logic_vector(0 TO 27);
    VARIABLE d2  : std_logic_vector(0 TO 27);
    VARIABLE d3  : std_logic_vector(0 TO 27);
    VARIABLE d4  : std_logic_vector(0 TO 27);
    VARIABLE d5  : std_logic_vector(0 TO 27);
    VARIABLE d6  : std_logic_vector(0 TO 27);
    VARIABLE d7  : std_logic_vector(0 TO 27);
    VARIABLE d8  : std_logic_vector(0 TO 27);
    VARIABLE d9  : std_logic_vector(0 TO 27);
    VARIABLE d10 : std_logic_vector(0 TO 27);
    VARIABLE d11 : std_logic_vector(0 TO 27);
    VARIABLE d12 : std_logic_vector(0 TO 27);
    VARIABLE d13 : std_logic_vector(0 TO 27);
    VARIABLE d14 : std_logic_vector(0 TO 27);
    VARIABLE d15 : std_logic_vector(0 TO 27);
    VARIABLE d16 : std_logic_vector(0 TO 27);
    -- key variables
    VARIABLE key1  : std_logic_vector(0 TO 47);
    VARIABLE key2  : std_logic_vector(0 TO 47);
    VARIABLE key3  : std_logic_vector(0 TO 47);
    VARIABLE key4  : std_logic_vector(0 TO 47);
    VARIABLE key5  : std_logic_vector(0 TO 47);
    VARIABLE key6  : std_logic_vector(0 TO 47);
    VARIABLE key7  : std_logic_vector(0 TO 47);
    VARIABLE key8  : std_logic_vector(0 TO 47);
    VARIABLE key9  : std_logic_vector(0 TO 47);
    VARIABLE key10 : std_logic_vector(0 TO 47);
    VARIABLE key11 : std_logic_vector(0 TO 47);
    VARIABLE key12 : std_logic_vector(0 TO 47);
    VARIABLE key13 : std_logic_vector(0 TO 47);
    VARIABLE key14 : std_logic_vector(0 TO 47);
    VARIABLE key15 : std_logic_vector(0 TO 47);
    VARIABLE key16 : std_logic_vector(0 TO 47);
    -- variables for left & right data blocks
    VARIABLE l0  : std_logic_vector( 0 TO 31);
    VARIABLE l1  : std_logic_vector( 0 TO 31);
    VARIABLE l2  : std_logic_vector( 0 TO 31);
    VARIABLE l3  : std_logic_vector( 0 TO 31);
    VARIABLE l4  : std_logic_vector( 0 TO 31);
    VARIABLE l5  : std_logic_vector( 0 TO 31);
    VARIABLE l6  : std_logic_vector( 0 TO 31);
    VARIABLE l7  : std_logic_vector( 0 TO 31);
    VARIABLE l8  : std_logic_vector( 0 TO 31);
    VARIABLE l9  : std_logic_vector( 0 TO 31);
    VARIABLE l10 : std_logic_vector( 0 TO 31);
    VARIABLE l11 : std_logic_vector( 0 TO 31);
    VARIABLE l12 : std_logic_vector( 0 TO 31);
    VARIABLE l13 : std_logic_vector( 0 TO 31);
    VARIABLE l14 : std_logic_vector( 0 TO 31);
    VARIABLE l15 : std_logic_vector( 0 TO 31);
    VARIABLE l16 : std_logic_vector( 0 TO 31);
    VARIABLE r0  : std_logic_vector( 0 TO 31);
    VARIABLE r1  : std_logic_vector( 0 TO 31);
    VARIABLE r2  : std_logic_vector( 0 TO 31);
    VARIABLE r3  : std_logic_vector( 0 TO 31);
    VARIABLE r4  : std_logic_vector( 0 TO 31);
    VARIABLE r5  : std_logic_vector( 0 TO 31);
    VARIABLE r6  : std_logic_vector( 0 TO 31);
    VARIABLE r7  : std_logic_vector( 0 TO 31);
    VARIABLE r8  : std_logic_vector( 0 TO 31);
    VARIABLE r9  : std_logic_vector( 0 TO 31);
    VARIABLE r10 : std_logic_vector( 0 TO 31);
    VARIABLE r11 : std_logic_vector( 0 TO 31);
    VARIABLE r12 : std_logic_vector( 0 TO 31);
    VARIABLE r13 : std_logic_vector( 0 TO 31);
    VARIABLE r14 : std_logic_vector( 0 TO 31);
    VARIABLE r15 : std_logic_vector( 0 TO 31);
    VARIABLE r16 : std_logic_vector( 0 TO 31);
    -- variables for mode & valid shift registers
    VARIABLE mode  : std_logic_vector(0 TO 16);
    VARIABLE valid : std_logic_vector(0 TO 17);
  BEGIN
    IF rising_edge( clk_i ) THEN
      -- shift registers
      valid(1 TO 17) := valid(0 TO 16);
      valid(0) := valid_i;
      mode(1 TO 16) := mode(0 TO 15);
      mode(0)  := mode_i;
      -- output stage
      valid_o <= valid(17);
      data_o  <= ipn( ( r16 & l16 ) );
      -- 16. stage
      IF mode(16) = '0' THEN
        c16 := c15(1 TO 27) & c15(0);
        d16 := d15(1 TO 27) & d15(0);
      ELSE
        c16 := c15(27) & c15(0 TO 26);
        d16 := d15(27) & d15(0 TO 26);
      END IF;
      key16 := pc2( ( c16 & d16 ) );
      l16 := r15;
      r16 := l15 xor ( f( r15, key16 ) );
      -- 15. stage
      IF mode(15) = '0' THEN
        c15 := c14(2 TO 27) & c14(0 TO 1);
        d15 := d14(2 TO 27) & d14(0 TO 1);
      ELSE
        c15 := c14(26 TO 27) & c14(0 TO 25);
        d15 := d14(26 TO 27) & d14(0 TO 25);
      END IF;
      key15 := pc2( ( c15 & d15 ) );
      l15 := r14;
      r15 := l14 xor ( f( r14, key15 ) );
      -- 14. stage
      IF mode(14) = '0' THEN
        c14 := c13(2 TO 27) & c13(0 TO 1);
        d14 := d13(2 TO 27) & d13(0 TO 1);
      ELSE
        c14 := c13(26 TO 27) & c13(0 TO 25);
        d14 := d13(26 TO 27) & d13(0 TO 25);
      END IF;
      key14 := pc2( ( c14 & d14 ) );
      l14 := r13;
      r14 := l13 xor ( f( r13, key14 ) );
      -- 13. stage
      IF mode(13) = '0' THEN
        c13 := c12(2 TO 27) & c12(0 TO 1);
        d13 := d12(2 TO 27) & d12(0 TO 1);
      ELSE
        c13 := c12(26 TO 27) & c12(0 TO 25);
        d13 := d12(26 TO 27) & d12(0 TO 25);
      END IF;
      key13 := pc2( ( c13 & d13 ) );
      l13 := r12;
      r13 := l12 xor ( f( r12, key13 ) );
      -- 12. stage
      IF mode(12) = '0' THEN
        c12 := c11(2 TO 27) & c11(0 TO 1);
        d12 := d11(2 TO 27) & d11(0 TO 1);
      ELSE
        c12 := c11(26 TO 27) & c11(0 TO 25);
        d12 := d11(26 TO 27) & d11(0 TO 25);
      END IF;
      key12 := pc2( ( c12 & d12 ) );
      l12 := r11;
      r12 := l11 xor ( f( r11, key12 ) );
      -- 11. stage
      IF mode(11) = '0' THEN
        c11 := c10(2 TO 27) & c10(0 TO 1);
        d11 := d10(2 TO 27) & d10(0 TO 1);
      ELSE
        c11 := c10(26 TO 27) & c10(0 TO 25);
        d11 := d10(26 TO 27) & d10(0 TO 25);
      END IF;
      key11 := pc2( ( c11 & d11 ) );
      l11 := r10;
      r11 := l10 xor ( f( r10, key11 ) );
      -- 10. stage
      IF mode(10) = '0' THEN
        c10 := c9(2 TO 27) & c9(0 TO 1);
        d10 := d9(2 TO 27) & d9(0 TO 1);
      ELSE
        c10 := c9(26 TO 27) & c9(0 TO 25);
        d10 := d9(26 TO 27) & d9(0 TO 25);
      END IF;
      key10 := pc2( ( c10 & d10 ) );
      l10 := r9;
      r10 := l9 xor ( f( r9, key10 ) );
      -- 9. stage
      IF mode(9) = '0' THEN
        c9 := c8(1 TO 27) & c8(0);
        d9 := d8(1 TO 27) & d8(0);
      ELSE
        c9 := c8(27) & c8(0 TO 26);
        d9 := d8(27) & d8(0 TO 26);
      END IF;
      key9 := pc2( ( c9 & d9 ) );
      l9 := r8;
      r9 := l8 xor ( f( r8, key9 ) );
      -- 8. stage
      IF mode(8) = '0' THEN
        c8 := c7(2 TO 27) & c7(0 TO 1);
        d8 := d7(2 TO 27) & d7(0 TO 1);
      ELSE
        c8 := c7(26 TO 27) & c7(0 TO 25);
        d8 := d7(26 TO 27) & d7(0 TO 25);
      END IF;
      key8 := pc2( ( c8 & d8 ) );
      l8 := r7;
      r8 := l7 xor ( f( r7, key8 ) );
      -- 7. stage
      IF mode(7) = '0' THEN
        c7 := c6(2 TO 27) & c6(0 TO 1);
        d7 := d6(2 TO 27) & d6(0 TO 1);
      ELSE
        c7 := c6(26 TO 27) & c6(0 TO 25);
        d7 := d6(26 TO 27) & d6(0 TO 25);
      END IF;
      key7 := pc2( ( c7 & d7 ) );
      l7 := r6;
      r7 := l6 xor ( f( r6, key7 ) );
      -- 6. stage
      IF mode(6) = '0' THEN
        c6 := c5(2 TO 27) & c5(0 TO 1);
        d6 := d5(2 TO 27) & d5(0 TO 1);
      ELSE
        c6 := c5(26 TO 27) & c5(0 TO 25);
        d6 := d5(26 TO 27) & d5(0 TO 25);
      END IF;
      key6 := pc2( ( c6 & d6 ) );
      l6 := r5;
      r6 := l5 xor ( f( r5, key6 ) );
      -- 5. stage
      IF mode(5) = '0' THEN
        c5 := c4(2 TO 27) & c4(0 TO 1);
        d5 := d4(2 TO 27) & d4(0 TO 1);
      ELSE
        c5 := c4(26 TO 27) & c4(0 TO 25);
        d5 := d4(26 TO 27) & d4(0 TO 25);
      END IF;
      key5 := pc2( ( c5 & d5 ) );
      l5 := r4;
      r5 := l4 xor ( f( r4, key5 ) );
      -- 4. stage
      IF mode(4) = '0' THEN
        c4 := c3(2 TO 27) & c3(0 TO 1);
        d4 := d3(2 TO 27) & d3(0 TO 1);
      ELSE
        c4 := c3(26 TO 27) & c3(0 TO 25);
        d4 := d3(26 TO 27) & d3(0 TO 25);
      END IF;
      key4 := pc2( ( c4 & d4 ) );
      l4 := r3;
      r4 := l3 xor ( f( r3, key4 ) );
      -- 3. stage
      IF mode(3) = '0' THEN
        c3 := c2(2 TO 27) & c2(0 TO 1);
        d3 := d2(2 TO 27) & d2(0 TO 1);
      ELSE
        c3 := c2(26 TO 27) & c2(0 TO 25);
        d3 := d2(26 TO 27) & d2(0 TO 25);
      END IF;
      key3 := pc2( ( c3 & d3 ) );
      l3 := r2;
      r3 := l2 xor ( f( r2, key3 ) );
      -- 2. stage
      IF mode(2) = '0' THEN
        c2 := c1(1 TO 27) & c1(0);
        d2 := d1(1 TO 27) & d1(0);
      ELSE
        c2 := c1(27) & c1(0 TO 26);
        d2 := d1(27) & d1(0 TO 26);
      END IF;
      key2 := pc2( ( c2 & d2 ) );
      l2 := r1;
      r2 := l1 xor ( f( r1, key2 ) );
      -- 1. stage
      IF mode(1) = '0' THEN
        c1 := c0(1 TO 27) & c0(0);
        d1 := d0(1 TO 27) & d0(0);
      ELSE
        c1 := c0;
        d1 := d0;
      END IF;
      key1 := pc2( ( c1 & d1 ) );
      l1 := r0;
      r1 := l0 xor ( f( r0, key1 ) );
      -- input stage
      l0 := ip( data_i )(0 TO 31);
      r0 := ip( data_i )(32 TO 63);
      c0 := pc1_c( key_i );
      d0 := pc1_d( key_i );
    END IF;
  END PROCESS crypt;

END ARCHITECTURE rtl;