{*_* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Author: Franois PIETTE
Creation: Sep 03, 2004
Version: 1.00
Description: DES encryption
Credit: Implementation of the Data Encryption Standard (DES) as
described in the book:
Schneier, B., "Applied Cryptography - Protocols Algorithms, and
source code in C", John Wiley & Sons, Inc. 1994.
Original turbo-pascal implementation by Menno Victor van der Star
. His code is available at
http://www.geocities.com/SiliconValley/2926/tpsrc/despas.txt
F. Piette updated the code to use typed parameters.
EMail: http://www.overbyte.be http://www.rtfm.be/fpiette
francois.piette@overbyte.be francois.piette@rtfm.be
francois.piette@pophost.eunet.be
Support: Use the mailing list twsocket@elists.org
Follow "support" link at http://www.overbyte.be for subscription.
Legal issues: Copyright (C) 2004-2005 by Franois PIETTE
Rue de Grady 24, 4053 Embourg, Belgium. Fax: +32-4-365.74.56
This software is provided 'as-is', without any express or
implied warranty. In no event will the author be held liable
for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any
purpose, including commercial applications, and to alter it
and redistribute it freely, subject to the following
restrictions:
1. The origin of this software must not be misrepresented,
you must not claim that you wrote the original software.
If you use this software in a product, an acknowledgment
in the product documentation would be appreciated but is
not required.
2. Altered source versions must be plainly marked as such, and
must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source
distribution.
4. You must register this software by sending a picture postcard
to the author. Use a nice stamp and mention your name, street
address, EMail address and any comment you like to say.
History:
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
unit IcsDES;
{$R-}
{$Q-}
{$I ICSDEFS.INC}
interface
const
IcsDESVersion = 100;
CopyRight : String = ' IcsDES (c) 2004-2005 F. Piette V1.00 ';
type
TArrayOf8Bytes = array [0..7] of Byte;
PArrayOf8Bytes = ^TArrayOf8Bytes;
procedure DES( { Function encrypt/decrypt data using DES algotithm }
const Input : TArrayOf8Bytes; { 64 bit of input }
var Output : TArrayOf8Bytes; { 64 bit output from DES algorithm }
const Key : TArrayOf8Bytes; { 64 bit key for DES algorithm }
Encrypt : Boolean); { TRUE to encrypt, FALSE to decrypt }
implementation
type
TArrayOf16Bytes = array [1..16] of Byte;
TArrayOf28Bytes = array [1..28] of Byte;
TArrayOf32Bytes = array [1..32] of Byte;
TArrayOf48Bytes = array [1..48] of Byte;
TArrayOf56Bytes = array [1..56] of Byte;
TArrayOf64Bytes = array [1..64] of Byte;
TDesData = record
InputValue : TArrayOf64Bytes;
OutputValue : TArrayOf64Bytes;
RoundKeys : array [1..16] of TArrayOf48Bytes;
L, R : TArrayOf32Bytes;
FunctionResult : TArrayOf32Bytes;
C, D : TArrayOf28Bytes;
end;
const
{ Initial Permutation }
IP : TArrayOf64Bytes = (58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7);
{ Final Permutation }
InvIP : TArrayOf64Bytes = (40, 8, 48, 16, 56, 24, 64, 32,
39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25);
{ Expansion Permutation }
E : TArrayOf48Bytes = (32, 1, 2, 3, 4, 5,
4, 5, 6, 7, 8, 9,
8, 9, 10, 11, 12, 13,
12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21,
20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29,
28, 29, 30, 31, 32, 1);
{ P-Box permutation }
P : TArrayOf32Bytes = (16, 7, 20, 21, 29, 12, 28, 17,
1, 15, 23, 26, 5, 18, 31, 10,
2, 8, 24, 14, 32, 27, 3, 9,
19, 13, 30, 6, 22, 11, 4, 25);
{ Key Permutation }
PC_1 : TArrayOf56Bytes = (57, 49, 41, 33, 25, 17, 9,
1, 58, 50, 42, 34, 26, 18,
10, 2, 59, 51, 43, 35, 27,
19, 11, 3, 60, 52, 44, 36,
63, 55, 47, 39, 31, 23, 15,
7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29,
21, 13, 5, 28, 20, 12, 4);
{ Compression Permutation }
PC_2 : TArrayOf48Bytes = (14, 17, 11, 24, 1, 5,
3, 28, 15, 6, 21, 10,
23, 19, 12, 4, 26, 8,
16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55,
30, 40, 51, 45, 33, 48,
44, 49, 39, 56, 34, 53,
46, 42, 50, 36, 29, 32);
{ Number of key bits shifted per round }
ST : TArrayOf16Bytes = ( 1, 1, 2, 2, 2, 2, 2, 2,
1, 2, 2, 2, 2, 2, 2, 1);
{ S-Boxes }
SBoxes : array [1..8, 0..3, 0..15] of Byte =
(((14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7),
( 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8),
( 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0),
(15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13)),
((15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10),
( 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5),
( 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15),
(13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9)),
((10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8),
(13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1),
(13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7),
( 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12)),
((7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15),
(13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9),
(10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4),
( 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14)),
((2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9),
(14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6),
( 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14),
(11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3)),
((12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11),
(10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8),
( 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6),
( 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13)),
((4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1),
(13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6),
( 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2),
( 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12)),
((13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7),
( 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2),
( 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8),
( 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11)));
{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
function GetBit(const Bits: TArrayOf8Bytes; Index: Byte): Byte;
begin
Dec(Index);
if Bits[Index div 8] and (128 shr(Index mod 8)) > 0 then
Result := 1
else
Result := 0;
end;
{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure SetBit(var Bits: TArrayOf8Bytes; Index, Value : Byte);
var
Bit: Byte;
begin
Dec(Index);
Bit := 128 shr(Index mod 8);
case Value of
0: Bits[Index div 8] := Bits[Index div 8] and (not Bit);
1: Bits[Index div 8] := Bits[Index div 8] or Bit;
end;
end;
{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure F(
var FR : TArrayOf32Bytes;
var FK : TArrayOf48Bytes;
var TotalOut : TArrayOf32Bytes);
var
Temp1 : TArrayOf48Bytes;
Temp2 : TArrayOf32Bytes;
n, h, i, j, Row, Column : Integer;
begin
for n := 1 to 48 do
Temp1[n] := FR[E[n]] xor FK[n];
for n := 1 to 8 do begin
i := (n - 1) * 6;
j := (n - 1) * 4;
Row := Temp1[i + 1] * 2 + Temp1[i + 6];
Column := Temp1[i + 2] * 8 + Temp1[i + 3] * 4 +
Temp1[i + 4] * 2 + Temp1[i + 5];
for h := 1 to 4 Do begin
case h of
1: Temp2[j + h] := (SBoxes[n, Row, Column] and 8) div 8;
2: Temp2[j + h] := (SBoxes[n, Row, Column] and 4) div 4;
3: Temp2[j + h] := (SBoxes[n, Row, Column] and 2) div 2;
4: Temp2[j + h] := (SBoxes[n, Row, Column] and 1);
end;
end;
end;
for n := 1 to 32 do
TotalOut[n] := Temp2[P[n]];
end;
{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure Shift(var SubKeyPart : TArrayOf28Bytes);
var
n, b: Byte;
begin
b := SubKeyPart[1];
for n := 1 to 27 do
SubKeyPart[n] := SubKeyPart[n + 1];
SubKeyPart[28] := b;
end;
{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure SubKey(
var DesData : TDesData;
Round : Byte;
var SubKey : TArrayOf48Bytes);
var
n, b : Byte;
begin
for n := 1 to ST[Round] do begin
Shift(DesData.C);
Shift(DesData.D);
end;
for n := 1 to 48 do begin
b := PC_2[n];
if b <= 28 then
SubKey[n] := DesData.C[b]
else
SubKey[n] := DesData.D[b - 28];
end;
end;
{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure DES(
const Input : TArrayOf8Bytes;
var Output : TArrayOf8Bytes;
const Key : TArrayOf8Bytes;
Encrypt : Boolean);
var
n, b, Round : Byte;
DesData : TDesData;
begin
for n := 1 to 64 do
DesData.InputValue[n] := GetBit(Input, n);
for n := 1 to 28 do begin
DesData.C[n] := GetBit(Key, PC_1[n]);
DesData.D[n] := GetBit(Key, PC_1[n + 28]);
end;
for n := 1 to 16 do
SubKey(DesData, n, DesData.RoundKeys[n]);
for n := 1 to 64 do begin
if n <= 32 then
DesData.L[n] := DesData.InputValue[IP[n]]
else
DesData.R[n - 32] := DesData.InputValue[IP[n]];
end;
for Round := 1 to 16 do begin
if Encrypt then
F(DesData.R, DesData.RoundKeys[Round], DesData.FunctionResult)
else
F(DesData.R, DesData.RoundKeys[17 - Round], DesData.FunctionResult);
for n := 1 to 32 do
DesData.FunctionResult[n] := DesData.FunctionResult[n] xor DesData.L[n];
DesData.L := DesData.R;
DesData.R := DesData.FunctionResult;
end;
for n := 1 to 64 do begin
b := InvIP[n];
if b <= 32 then
DesData.OutputValue[n] := DesData.R[b]
else
DesData.OutputValue[n] := DesData.L[b-32];
end;
for n := 1 to 64 do
SetBit(Output, n, DesData.OutputValue[n]);
end;
{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}