发信人: delphi5537()
整理人: teleme(2001-06-05 08:46:57), 站内信件
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【 在 x_savege 的大作中提到：】
:哪位老兄知道哪里有加密文件例程，完整一点的
:......
下面历程使用Rc6加密方法
unit RC6unit;
interface
uses
Windows, Messages, SysUtils, Classes,
Graphics, Controls, Forms, Dialogs;
const
c = 8; //# of key (32bit) words (this is a 192bit key increase # of words for more security can be expandable up to 256 bits)
r = 20; //# of rounds (can be changed if desired)
type
array1 = array[0..c-1] of integer;
array2 = array[0..2*r+3] of integer;
array3 = array[0..3] of integer;
TRC6 = class(Tcomponent)
private
Ikey : string; {internal key of the component Key is 192-bits}
IFile : string; {input file}
OFile : string; {output file}
function getfirstbits(a : integer; amount : byte): byte;
function keyexpand: array2;
procedure rotrword(d : array3); //move the words right 1
procedure rotlword(d : array3); //move the words right 1
function f(b : integer): integer;
{Encrypt/decrypt block}
function encryptblock(d : array3; S : array2): array3;
function decryptblock(d : array3; S : array2): array3;
public
property Key : string read Ikey write Ikey; {property used to get the key}
property InputFile : string read IFile write IFile;
property OutputFile : string read Ofile write Ofile;
function testcipher: string;
procedure encipherfile;
procedure decipherfile;
end;
procedure Register;
implementation
const
twoto32 = 2147483647{*2};//if you have Delphi 4 erase the brackets around the {*2} and change all the integer types to unsigned integers
bits = 5;//number of bits that can get 32 combos
procedure Register;
begin
RegisterComponents('histar', [TRC6]);
end;
{******************}
{******************}
{******************}
//fast rotations in assembler!!!!
Function ROTL(A: Longint; Amount: BYTE): Longint; Assembler;
asm
mov cl, Amount
rol eax, cl
end;
Function ROTR(A: Longint; Amount: BYTE): Longint; Assembler;
asm
mov cl, Amount
ror eax, cl
end;
//if you don't run on a intel or compatible you can use these routines instead
{
Function ROTL(A: integer; Amount: BYTE): integer;
begin
ROTL := (a shL amount)or(a shr (32-amount));
end;
Function ROTR(A: integer; Amount: BYTE): integer;
begin
ROTR := (a shr amount)or(a shl (32-amount));
end;
}
function TRC6.getfirstbits(a : integer; amount : byte): byte;
var
b : byte;
begin
b := a shl amount;
getfirstbits := b shr amount;
end;
{******************}
{******************}
{******************}
function TRC6.keyexpand: array2;
const
P = $B7E1f4b2;
Q = $9E37376a;
var
i,A,B,j,v,k : integer;
S : array2;
strn : string[32];
key : array1;
begin
{the user can pass any key length up to 256-bits}
strn := copy(ikey,1,length(ikey));;
for i := length(ikey) to 32 do
strn[i] := #0;{Pad the key with nulls}
key[0] := 0;key[4] := 0;
key[1] := 0;key[5] := 0;
key[2] := 0;key[6] := 0;
key[3] := 0;key[7] := 0;
move(strn,key,sizeof(key));
S[0] := P;
for i := 1 to (2*r+3) do
S[i] := S[i-1] + Q;
A := 0;B := 0;i := 0;j := 0;
v := 3 * (2*r-4);
for k := 1 to v do
begin
S[i] := rotl(S[i]+A+B,3);
A := S[i];
Key[j] := rotl(key[j]+A+B,(A+B) and 31);
i := (i+1)mod (2*r+4);
j := (j+1)mod c;
end;
keyexpand := S;
end;
{******************}
{******************}
{******************}
function TRC6.f(b : integer): integer;
begin
f := (b*(2*b+1))mod twoto32;
end;
{******************}
procedure TRC6.rotlword(d : array3); //move the words right 1
var
b : array3;
begin
b[0] := d[1]; b[1] := d[2]; b[2] := d[3]; b[3] := d[0];
d := b;
end;
{******************}
procedure TRC6.rotrword(d : array3); //move the words right 1
var
b : array3;
begin
b[0] := d[3]; b[1] := d[0]; b[2] := d[1]; b[3] := d[2];
d := b;
end;
{******************}
{******************}
{******************}
function TRC6.encryptblock(d : array3; S : array2): array3;
var
t,u,i : integer;
begin
d[1] := d[1] + S[0] mod twoto32;
d[3] := d[3] + S[1] mod twoto32;
for i := 1 to r do
begin
t := rotl(f(d[1]), bits);
u := rotl(f(d[3]), bits);
d[0] := (rotl(d[0] xor t,u and 31)+S[2*i]) mod twoto32;
d[2] := (rotl(d[2] xor u,t and 31)+S[2*i+1]) mod twoto32;
rotlword(d);
end;
d[0] := (d[0] + S[2*r+2]) mod twoto32;
d[2] := (d[2] + S[2*r+3]) mod twoto32;
encryptblock := d;
end;
{******************}
{******************}
{******************}
function TRC6.decryptblock(d : array3; S : array2): array3;
var
t,u,i : integer;
begin
d[0] := (d[0] - S[2*r+2]) mod twoto32;
d[2] := (d[2] - S[2*r+3]) mod twoto32;
for i := r downto 1 do
begin
rotrword(d);
t := rotl(f(d[1]), bits);
u := rotl(f(d[3]), bits);
d[0] := (rotr(d[0]-S[2*i],u and 31) xor t) mod twoto32;
d[2] := (rotr(d[2]-S[2*i+1],t and 31) xor u) mod twoto32;
end;
d[1] := (d[1] - S[0]) mod twoto32;
d[3] := (d[3] - S[1]) mod twoto32;
decryptblock := d;
end;
{******************}
{******************}
{******************}
function TRC6.testcipher: string;
var
arr : array3;
strn : string[16];
S : array2;
begin
key := '瞳壴;m馘% 娹#駜幭慴I?;
strn := 'Hello RC6 Cipher';
move(strn,arr,sizeof(strn));
S := keyexpand;
arr := encryptblock(arr, S);
S := keyexpand;
arr := decryptblock(arr, S);
strn := '';
move(arr,strn,sizeof(arr));
testcipher := strn+'!';
end;
{******************}
{******************}
{******************}
procedure TRC6.encipherfile;
var
S : array2;
i,numread,numwritten : integer;
buff : array[0..4095] of char;
buff2 : array[0..1023] of integer;
a : array3;
inputf,outputf : file;
begin
assignfile(inputf,ifile);{These are the input and output files}
reset(inputf,1);
assignfile(outputf, ofile);
rewrite(Outputf,1);
S := keyexpand;
repeat
blockread(inputf,Buff,sizeof(buff), numread);
move(Buff,buff2,sizeof(buff));
i := 0;
while i <= 1023 do
begin
{get the plaintext text}
a[0] := buff2[i];
a[1] := buff2[i+1];
a[2] := buff2[i+2];
a[3] := buff2[i+3];
a := encryptblock(a,S);
{return the encrypted values}
buff2[i] := a[0];
buff2[i+1] := a[1];
buff2[i+2] := a[2];
buff2[i+3] := a[3];
inc(i,4);
end;{while}
move(Buff2,buff,sizeof(buff2));
blockwrite(outputf,Buff,numread, numwritten);
until (numread = 0) or (numwritten <> numread);
closefile(inputf);
closefile(outputf);
end;
{******************}
procedure TRC6.decipherfile;
var
S : array2;
i,numread,numwritten : integer;
buff : array[0..4095] of char;
buff2 : array[0..1023] of integer;
a : array3;
inputf,outputf : file;
begin
assignfile(inputf,ifile);{These are the input and output files}
reset(inputf,1);
assignfile(outputf, ofile);
rewrite(Outputf,1);
S := keyexpand;
repeat
blockread(inputf,Buff,sizeof(buff), numread);
move(Buff,buff2,sizeof(buff));
i := 0;
while i <= 1023 do
begin
{get the cipher text}
a[0] := buff2[i];
a[1] := buff2[i+1];
a[2] := buff2[i+2];
a[3] := buff2[i+3];
a := decryptblock(a,S);
{return the decrypted values}
buff2[i] := a[0];
buff2[i+1] := a[1];
buff2[i+2] := a[2];
buff2[i+3] := a[3];
inc(i,4);
end;{while}
move(Buff2,buff,sizeof(buff2));
blockwrite(outputf,Buff,numread,numwritten);
until (numread = 0) or (numwritten <> numread);
closefile(inputf);
closefile(outputf);
end;
end. |
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