unit Des; 

interface 

uses SysUtils; 

type 
  TKeyByte = array[0..5] of Byte; 
  TDesMode = (dmEncry, dmDecry); 

  function EncryStr(Str, Key: String): String; 
  function DecryStr(Str, Key: String): String; 
  function EncryStrHex(Str, Key: String): String; 
  function DecryStrHex(StrHex, Key: String): String; 

const 
  BitIP: array[0..63] of Byte = 
    (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, 
     56, 48, 40, 32, 24, 16,  8,  0, 
     58, 50, 42, 34, 26, 18, 10,  2, 
     60, 52, 44, 36, 28, 20, 12,  4, 
     62, 54, 46, 38, 30, 22, 14,  6 ); 

  BitCP: array[0..63] of Byte = 
    ( 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, 
      32,  0, 40,  8, 48, 16, 56, 24 ); 

  BitExp: array[0..47] of Integer = 
    ( 31, 0, 1, 2, 3, 4, 3, 4, 5, 6, 7, 8, 7, 8, 9,10, 
      11,12,11,12,13,14,15,16,15,16,17,18,19,20,19,20, 
      21,22,23,24,23,24,25,26,27,28,27,28,29,30,31,0  ); 

  BitPM: array[0..31] of Byte = 
    ( 15, 6,19,20,28,11,27,16, 0,14,22,25, 4,17,30, 9, 
       1, 7,23,13,31,26, 2, 8,18,12,29, 5,21,10, 3,24 ); 

  sBox: array[0..7] of array[0..63] 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 ) ); 

  BitPMC1: array[0..55] of Byte = 
    ( 56, 48, 40, 32, 24, 16,  8, 
       0, 57, 49, 41, 33, 25, 17, 
       9,  1, 58, 50, 42, 34, 26, 
      18, 10,  2, 59, 51, 43, 35, 
      62, 54, 46, 38, 30, 22, 14, 
       6, 61, 53, 45, 37, 29, 21, 
      13,  5, 60, 52, 44, 36, 28, 
      20, 12,  4, 27, 19, 11,  3 ); 

  BitPMC2: array[0..47] of Byte = 
    ( 13, 16, 10, 23,  0,  4, 
       2, 27, 14,  5, 20,  9, 
      22, 18, 11,  3, 25,  7, 
      15,  6, 26, 19, 12,  1, 
      40, 51, 30, 36, 46, 54, 
      29, 39, 50, 44, 32, 47, 
      43, 48, 38, 55, 33, 52, 
      45, 41, 49, 35, 28, 31 ); 

var 
  subKey: array[0..15] of TKeyByte; 
       
implementation 
procedure initPermutation(var inData: array of Byte); 
var 
  newData: array[0..7] of Byte; 
  i: Integer; 
begin 
  FillChar(newData, 8, 0); 
  for i := 0 to 63 do 
    if (inData[BitIP[i] shr 3] and (1 shl (7- (BitIP[i] and $07))))  < > 0 then 
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07))); 
  for i := 0 to 7 do inData[i] := newData[i]; 
end; 

procedure conversePermutation(var inData: array of Byte); 
var 
  newData: array[0..7] of Byte; 
  i: Integer; 
begin 
  FillChar(newData, 8, 0); 
  for i := 0 to 63 do 
    if (inData[BitCP[i] shr 3] and (1 shl (7-(BitCP[i] and $07))))  < > 0 then 
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07))); 
  for i := 0 to 7 do inData[i] := newData[i]; 
end; 

procedure expand(inData: array of Byte; var outData: array of Byte); 
var 
  i: Integer; 
begin 
  FillChar(outData, 6, 0); 
  for i := 0 to 47 do 
    if (inData[BitExp[i] shr 3] and (1 shl (7-(BitExp[i] and $07))))  < > 0 then 
      outData[i shr 3] := outData[i shr 3] or (1 shl (7-(i and $07))); 
end; 

procedure permutation(var inData: array of Byte); 
var 
  newData: array[0..3] of Byte; 
  i: Integer; 
begin 
  FillChar(newData, 4, 0); 
  for i := 0 to 31 do 
    if (inData[BitPM[i] shr 3] and (1 shl (7-(BitPM[i] and $07))))  < > 0 then 
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07))); 
  for i := 0 to 3 do inData[i] := newData[i]; 
end; 

function si(s,inByte: Byte): Byte; 
var 
  c: Byte; 
begin 
  c := (inByte and $20) or ((inByte and $1e) shr 1) or 
    ((inByte and $01) shl 4); 
  Result := (sBox[s][c] and $0f); 
end; 

procedure permutationChoose1(inData: array of Byte; 
  var outData: array of Byte); 
var 
  i: Integer; 
begin 
  FillChar(outData, 7, 0); 
  for i := 0 to 55 do 
    if (inData[BitPMC1[i] shr 3] and (1 shl (7-(BitPMC1[i] and $07))))  < > 0 then 
      outData[i shr 3] := outData[i shr 3] or (1 shl (7-(i and $07))); 
end; 

procedure permutationChoose2(inData: array of Byte; 
  var outData: array of Byte); 
var 
  i: Integer; 
begin 
  FillChar(outData, 6, 0); 
  for i := 0 to 47 do 
    if (inData[BitPMC2[i] shr 3] and (1 shl (7-(BitPMC2[i] and $07))))  < > 0 then 
      outData[i shr 3] := outData[i shr 3] or (1 shl (7-(i and $07))); 
end; 

procedure cycleMove(var inData: array of Byte; bitMove: Byte); 
var 
  i: Integer; 
begin 
  for i := 0 to bitMove - 1 do 
  begin 
    inData[0] := (inData[0] shl 1) or (inData[1] shr 7); 
    inData[1] := (inData[1] shl 1) or (inData[2] shr 7); 
    inData[2] := (inData[2] shl 1) or (inData[3] shr 7); 
    inData[3] := (inData[3] shl 1) or ((inData[0] and $10) shr 4); 
    inData[0] := (inData[0] and $0f); 
  end; 
end; 

procedure makeKey(inKey: array of Byte; var outKey: array of TKeyByte); 
const 
  bitDisplace: array[0..15] of Byte = 
    ( 1,1,2,2, 2,2,2,2, 1,2,2,2, 2,2,2,1 ); 
var 
  outData56: array[0..6] of Byte; 
  key28l: array[0..3] of Byte; 
  key28r: array[0..3] of Byte; 
  key56o: array[0..6] of Byte; 
  i: Integer; 
begin 
  permutationChoose1(inKey, outData56); 

  key28l[0] := outData56[0] shr 4; 
  key28l[1] := (outData56[0] shl 4) or (outData56[1] shr 4); 
  key28l[2] := (outData56[1] shl 4) or (outData56[2] shr 4); 
  key28l[3] := (outData56[2] shl 4) or (outData56[3] shr 4); 
  key28r[0] := outData56[3] and $0f; 
  key28r[1] := outData56[4]; 
  key28r[2] := outData56[5]; 
  key28r[3] := outData56[6]; 

  for i := 0 to 15 do 
  begin 
    cycleMove(key28l, bitDisplace[i]); 
    cycleMove(key28r, bitDisplace[i]); 
    key56o[0] := (key28l[0] shl 4) or (key28l[1] shr 4); 
    key56o[1] := (key28l[1] shl 4) or (key28l[2] shr 4); 
    key56o[2] := (key28l[2] shl 4) or (key28l[3] shr 4); 
    key56o[3] := (key28l[3] shl 4) or (key28r[0]); 
    key56o[4] := key28r[1]; 
    key56o[5] := key28r[2]; 
    key56o[6] := key28r[3]; 
    permutationChoose2(key56o, outKey[i]); 
  end; 
end; 

procedure initPermutation(var inData: array of Byte); 
var 
  newData: array[0..7] of Byte; 
  i: Integer; 
begin 
  FillChar(newData, 8, 0); 
  for i := 0 to 63 do 
    if (inData[BitIP[i] shr 3] and (1 shl (7- (BitIP[i] and $07))))  < > 0 then 
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07))); 
  for i := 0 to 7 do inData[i] := newData[i]; 
end; 

procedure conversePermutation(var inData: array of Byte); 
var 
  newData: array[0..7] of Byte; 
  i: Integer; 
begin 
  FillChar(newData, 8, 0); 
  for i := 0 to 63 do 
    if (inData[BitCP[i] shr 3] and (1 shl (7-(BitCP[i] and $07))))  < > 0 then 
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07))); 
  for i := 0 to 7 do inData[i] := newData[i]; 
end; 

procedure expand(inData: array of Byte; var outData: array of Byte); 
var 
  i: Integer; 
begin 
  FillChar(outData, 6, 0); 
  for i := 0 to 47 do 
    if (inData[BitExp[i] shr 3] and (1 shl (7-(BitExp[i] and $07))))  < > 0 then 
      outData[i shr 3] := outData[i shr 3] or (1 shl (7-(i and $07))); 
end;