Реферат: Шифрование DES - теория и практика
XOR R(1)=10011001011001010011101110010001
L(1) = R(0)
В итоге этих действий появляется новая правая половина, а старая правая половина становится новой левой. Эти действия повторяются 16 раз, образуя 16 этапов DES.
L(1) = 11111111111111110101001101110000
R(1) =
10011001011001010011101110010001
E(R1) = 110011110010101100001010100111110111110010100011
R(1) XOR K(2) = 100111111000011110101110110011111101111111100100
S(1..8) = 00101001100011011111100011000100
P = 10110001000111000101001111100001
R(1) XOR L(1) = 01001110111000110000000010010001 =
R(2)
L(2) = R(1) = 10011001011001010011101110010001
E(R2) = 101001011101011100000110100000000001010010100010
R(2) XOR K(3) = 011101010111101100100000011101101001000000101110
S(1..8) = 00111010001110101000100101000010
P = 01010101010110100010001001000110
R(2) XOR L(2) = 11001100001111110001100111010111 =
R(3)
L(3) = R(2) = 01001110111000110000000010010001
E(R3) = 111001011000000111111110100011110011111010101111
R(3) XOR K(4) = 000001010010011111011000110001110000100101100100
S(1..8) = 00000111000110110110011111010100
P = 11000110011101000110000011111001
R(3) XOR L(3) = 10001000100101110110000001101000 =
R(4)
L(4) = R(3) = 11001100001111110001100111010111
E(R4) = 010001010001010010101110101100000000001101010001
R(4) XOR K(5) = 101001011000001010001000100011101111001101111000
S(1..8) = 01001100001100001000101000011100
P = 00011111001010001000000000110100
R(4) XOR L(4) = 11010011000101111001100111100011 =
R(5)
L(5) = R(4) = 10001000100101110110000001101000
E(R5) = 111010100110100010101111110011110011111100000111
R(5) XOR K(6) = 000010101111101011011101101011010110001001100101
S(1..8) = 01000010100111101110010001001110
P = 01001101010101101001000111101000
R(5) XOR L(5) = 11000101110000011111000110000000 = R(6)
L(6) = R(5) = 11010011000101111001100111100011
E(R6) = 011000001011111000000011111110100011110000000001
R(6) XOR K(7) = 110001000110110001110001011101101001010100111011
S(1..8) = 01011110010010011000100110010101
P = 11010011000010011010100001110011
R(6) XOR L(6) = 00000000000111100011000110010000 =
R(7)
L(7) = R(6) = 11000101110000011111000110000000
E(R7) = 000000000000000011111100000110100011110010100000
R(7) XOR K(8) = 101001100101001110101110111111110110001011110000
S(1..8) = 01001010010111110011101010010000
P = 11110110011010011001000011000001
R(7) XOR L(7) = 00110011101010000110000101000001 =
R(8)
L(8) = R(7) = 00000000000111100011000110010000
E(R8) = 100110100111110101010000001100000010101000000010
R(8) XOR K(9) = 101111000010111000000011111110111011000001000010
S(1..8) = 01110001010110001110000010110010
P = 00000111000001111100011011000011
R(8) XOR L(8) = 00000111000110011111011101010011 =
R(9)
L(9) = R(8) = 00110011101010000110000101000001
E(R9) = 100000001110100011110011111110101110101010100110
R(9) XOR K(10) = 101011111011100110100010001010100010110110011010
S(1..8) = 10010101100101101010111010000000
P = 00010101111000000101000110011011
R(9) XOR L(9) = 00100110010010000011000011011010 =
R(10)
L(10) = R(9) = 00000111000110011111011101010011
E(R10) = 000100001100001001010000000110100001011011110100
R(10) XOR K(11) = 000111111000001110001001000000110000100001111000
S(1..8) = 01001001010101100010011101101111
P = 00001100011110111111110010101000
R(10) XOR L(10) = 00001011011000100000101111111011 =
R(11)
L(11) = R(10) = 00100110010010000011000011011010
E(R11) = 100001010110101100000100000001010111111111110110
R(11) XOR K(12) = 100110100010101010011101110111010000111101000111
S(1..8) = 10001110111111101001000000111000
P = 01101111110010010001010101010100
R(11) XOR L(11) = 01001001100000010010010110001110 =
R(12)
L(12) = R(11) = 00001011011000100000101111111011
E(R12) = 001001010011110000000010100100001011110001011100
R(12) XOR K(13) = 001110100011010110001011101100111101011001110001
S(1..8) = 10001000011111110111100000101111
P = 10111100110011110001110011100100
R(12) XOR L(12) = 10110111101011010001011100011111 =
R(13)
L(13) = R(12) = 01001001100000010010010110001110
E(R13) = 110110101111110101011010100010101110100011111111
R(13) XOR K(14) = 110000011101010111010111001110001101000101101101
S(1..8) = 11111011111011000110100110111000
P = 01011010100011011111011111000111
R(13) XOR L(13) = 00010011000011001101001001001001 =
R(14)
L(14) = R(13) = 10110111101011010001011100011111
E(R14) = 100010100110100001011001011010100100001001010010
R(14) XOR K(15) = 100100110100010011010101110011110100000101100101
S(1..8) = 11101100100000101111010010111110
P = 00101011110011101000011110111001
R(14) XOR L(14) = 10011100011000111001000010100110 =
R(15)
L(15) = R(14) = 00010011000011001101001001001001
E(R15) = 010011111000001100000111110010100001010100001101
R(15) XOR K(16) = 000111101010111110001011011011010101011011001101
S(1..8) = 01000100011111111001110111110111
P = 10110111010100111011110001111101
R(15) XOR L(15) = 10100100010111110110111000110100 = R(16)
L(16) = R(15) = 10011100011000111001000010100110
Шаг 9 заключительная перестановка(обратная)
| 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 |
Вход (L16R16) = 1001110001100011100100001010011010100100010111110110111000110100
Полученная = 00110000 00111001 11101011 01101000 01100110 10011011 00111000 11000101 =
48 57 235 104 102 155 56 197 = 0 9 л h f > 8 Е
Программа
Шифрование
Расшифровка
Текст программы
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);
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 // ïåðåâîðîò ñòðîêè
begin
str[ost]:= st[q];
Inc(ost);
end;
case Length(st) of
1: Insert('0000000', str, 1); // äîáàâëåíèå íåäîñòàþùèõ íîëåé
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'));
