Разработка программы шифрования и дешифрования текста методом DES

unit Unit1; 

interface 

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls; 

type

  TForm1 = class(TForm)

    Memo1: TMemo;

    Memo2: TMemo;

    Label1: TLabel;

    Label2: TLabel;

    Button1: TButton;

    Button2: TButton;

    Memo3: TMemo;

    Label3: TLabel;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end; 

var

  Form1: TForm1;

  c, d, k: array [0..16] of AnsiString;

  r, l, rez, z: AnsiString;

  w, desK, desR: byte;

implementation 

{$R *.dfm} 
 

procedure DecToBin(input: string; var output: ansistring); десятичное в двоичное

var

  a, b: double;

  ost, q, w: byte;

  st: AnsiString;

  str: string[8];

begin

  str:= '        ';

  for w:= 1 to 8 do

    begin

      q:= Ord(input[w]);

      b:= q;

      While b <> 1 do

        begin

          a:= q / 2;

          b:= Int(a);

          if a = b then

            ost:= 0

          else ost:= 1;

          q:= Round(b);

          st:= st + IntToStr(ost);

          if b = 1 then st:= st + '1';

        end;

      ost:= 1;

      for q:= Length(st) downto 1 do  // переворот строки

        begin

          str[ost]:= st[q];

          Inc(ost);

        end;

      case Length(st) of

        1: Insert('0000000', str, 1);   // добавление недостающих нолей

        2: Insert('000000', str, 1);

        3: Insert('00000', str, 1);

        4: Insert('0000', str, 1);

        5: Insert('000', str, 1);

        6: Insert('00', str, 1);

        7: Insert('0', str, 1);

      end;

      output:= output + str;// + '  ';

      str:= '        ';

      st:= '';

    end;

end; 
 
 

procedure BeginPerestanovka(input: ansistring; var output: ansistring);

begin

  output:=

    input[58] + input[50] + input[42] + input[34] + input[26] + input[18]

  + input[10] + input[2]

  + input[60] + input[52] + input[44] + input[36] + input[28] + input[20]

  + input[12] + input[4]

  + input[62] + input[54] + input[46] + input[38] + input[30] + input[22]

  + input[14] + input[6]

  + input[64] + input[56] + input[48] + input[40] + input[32] + input[24]

  + input[16] + input[8]

  + input[57] + input[49] + input[41] + input[33] + input[25] + input[17]

  + input[9] + input[1]

  + input[59] + input[51] + input[43] + input[35] + input[27] + input[19]

  + input[11] + input[3]

  + input[61] + input[53] + input[45] + input[37] + input[29] + input[21]

  + input[13] + input[5]

  + input[63] + input[55] + input[47] + input[39] + input[31] + input[23]

  + input[15] + input[7];

end; 
 

procedure PerestanovkaKeyB(input: AnsiString; var output: AnsiString);

begin

  output:= '';

  output:=

    input[57]+input[49]+input[41]+input[33]+input[25]+input[17]+input[9]

   +input[1]+input[58]+input[50]+input[42]+input[34]+input[26]+input[18]

   +input[10]+input[2]+input[59]+input[51]+input[43]+input[35]+input[27]

   +input[19]+input[11]+input[3]+input[60]+input[52]+input[44]+input[36]

   +input[63]+input[55]+input[47]+input[39]+input[31]+input[23]+input[15]

   +input[7]+input[62]+input[54]+input[46]+input[38]+input[30]+input[22]

   +input[14]+input[6]+input[61]+input[53]+input[45]+input[37]+input[29]

   +input[21]+input[13]+input[5]+input[28]+input[20]+input[12]+input[4];

end; 

procedure pocledovatelnostiK;

var

  w: byte;

  bufer: AnsiString;

begin

  for w:= 0 to 16 do

    begin

      bufer:= Concat(c[w], d[w]);

      k[w]:=

      Concat(bufer[14], bufer[17], bufer[11], bufer[24], bufer[1], bufer[5],

             bufer[3], bufer[28], bufer[15], bufer[6], bufer[21], bufer[10],

             bufer[23], bufer[19], bufer[12], bufer[4], bufer[26], bufer[8],

             bufer[16], bufer[7], bufer[27], bufer[20], bufer[13], bufer[2],

             bufer[41], bufer[52], bufer[31], bufer[37], bufer[47], bufer[55],

             bufer[30], bufer[40], bufer[51], bufer[45], bufer[33], bufer[48],

             bufer[44], bufer[49], bufer[39], bufer[56], bufer[34], bufer[53],

             bufer[46], bufer[42], bufer[50], bufer[36], bufer[29], bufer[32]);

    end;

end; 

procedure FuncE;

const

  s1 : array[0..3, 0..15] of string[4] =

  (('1110','0100','1101','0001','0010','1111','1011','1000','0011','1010','0110','1100','0101','1001','0000','0111'),

  ('0000','1111','0111','0100','1110','0010','1101','0001','1010','0110','1100','1011','1001','0101','0011','1000'),

  ('0100','0001','1110','1000','1001','0110','0010','1011','1111','1100','1001','0111','0011','1010','0101','0000'),

  ('1111','1100','1000','0010','0100','1001','0001','0111','0101','1011','0011','1110','1010','0000','1001','1101'));

  s2 : array[0..3, 0..15] of string[4] =

  (('1111','0001','1000','1110','0110','1011','0011','0100','1001','0111','0010','1101','1100','0000','0101','1010'),

  ('0011','1101','0100','0111','1111','0010','1000','1110','1100','0000','0001','1010','0110','1001','1011','0101'),

  ('0000','1110','0111','1011','1010','0100','1101','0001','0101','1000','1100','0110','1001','0011','0010','1111'),

  ('1101','1000','1010','0001','0011','1111','0100','0010','1011','0110','0111','1100','0000','0101','1110','1001'));

  s3 : array [0..3, 0..15] of string[4] =

  (('1010','0000','1001','1110','0110','0011','1111','0101','0001','1101','1100','0111','1011','0100','0010','1000'),

  ('1101','0111','0000','1001','0011','0100','0110','1010','0010','1000','0101','1110','1100','1011','1111','0001'),

  ('1101','0110','0100','1001','1000','1111','0011','0000','1011','0001','0010','1100','0101','1010','1110','0111'),

  ('0001','1010','1101','0000','0110','1001','1000','0111','0100','1111','1110','0011','1011','0101','0010','1100'));

  s4 : array [0..3, 0..15] of string[4] =

  (('0111','1101','1110','0011','0000','0110','1001','1010','0001','0010','1000','0101','1011','1100','0100','1111'),

  ('1101','1000','1011','0101','0110','1111','0000','0011','0100','0111','0010','1100','0001','1010','1110','1001'),

  ('1010','0110','1001','0000','1100','1011','0111','1101','1111','0001','0011','1110','0101','0010','1000','0100'),

  ('0011','1111','0000','0110','1010','0001','1101','1000','1001','0100','0101','1011','1100','0111','0010','1110'));

  s5 : array [0..3, 0..15] of string[4] =

  (('0010','1100','0100','0001','0111','1010','1011','0110','1000','0101','0011','1111','1101','0000','1110','1001'),

  ('1110','1011','0010','1100','0100','0111','1101','0001','0101','0000','1111','1010','0011','1001','1000','0110'),

  ('0100','0010','0001','1011','1010','1101','0111','1000','1111','1001','1100','0101','0110','0011','0000','1110'),

  ('1011','1000','1100','0111','0001','1110','0010','1101','0110','1111','0000','1001','1010','0100','0101','0011'));

  s6 : array [0..3, 0..15] of string[4] =

  (('1100','0001','1010','1111','1001','0010','0110','1000','0000','1101','0011','0100','1110','0111','0101','1011'),

  ('1010','1111','0100','0010','0111','1100','1001','0101','0110','0001','1101','1110','0000','1011','0011','1000'),

  ('1001','1110','1111','0101','0010','1000','1100','0011','0111','0000','0100','1010','0001','1101','1011','0110'),

  ('0100','0011','0010','1100','1001','0101','1111','1010','1011','1110','0001','0111','0110','0000','1000','1101'));

  s7 : array [0..3, 0..15] of string[4] =

  (('0100','1011','0010','1110','1111','0000','1000','1101','0011','1100','1001','0111','0101','1010','0110','0001'),

  ('1101','0000','1011','0111','0100','1001','0001','1010','1110','0011','0101','1100','0011','1111','1000','0110'),

  ('0001','0100','1011','1101','1100','0011','0111','1110','1010','1111','0110','1000','0000','0101','1001','0010'),

  ('0110','1011','1101','1000','0001','0100','1010','0111','1001','0101','0000','1111','1110','0010','0011','1100'));

  s8 : array [0..3, 0..15] of string[4] =

  (('1101','0010','1000','0100','0110','1111','1011','0001','1010','1001','0011','1110','0101','0000','1100','0111'),