Simple crypt functions

Yaroslav_Gaponov

Hi All

Simple crypt method base on key and ... cards

OBJECT Codeunit 70000 Crypto Cards
{
  OBJECT-PROPERTIES
  {
    Date=12-06-08;
    Time=[ 1:48:12 ];
    Modified=Yes;
    Version List=;
  }
  PROPERTIES
  {
    OnRun=BEGIN
            Code('c:\cards.key','c:\file.txt','c:\file.___');
            Decode('c:\cards.key','c:\file.___','c:\file2.txt');
          END;

  }
  CODE
  {
    VAR
      Cards@1000 : ARRAY [256] OF Integer;

    LOCAL PROCEDURE Initialize@2();
    VAR
      i@1000 : Integer;
    BEGIN
      FOR i := 0 TO 255 DO
        Cards[i+1] := i;
    END;

    LOCAL PROCEDURE Shuffle@1();
    VAR
      p@1002 : ARRAY [2] OF Integer;
      i@1000 : Integer;
    BEGIN
      FOR i := 1 TO RANDOM(10) DO
        p[1] := RANDOM(256);
      FOR i := 1 TO RANDOM(10) DO
        p[2] := RANDOM(256);

      Cards[p[1]] := Cards[p[1]] - Cards[p[2]];
      Cards[p[2]] := Cards[p[1]] + Cards[p[2]];
      Cards[p[1]] := Cards[p[2]] - Cards[p[1]];
    END;

    LOCAL PROCEDURE Save@3(Name@1000 : Text[250]);
    VAR
      F@1001 : File;
      i@1002 : Integer;
      c@1003 : Char;
    BEGIN
      F.TEXTMODE := FALSE;
      F.WRITEMODE := TRUE;
      F.CREATE(Name);
      FOR i := 1 TO 256 DO BEGIN
        c := Cards[i];
        F.WRITE(c);
      END;
      F.CLOSE;
    END;

    PROCEDURE CreateCards@4(Name@1000 : Text[250]);
    VAR
      i@1001 : Integer;
    BEGIN
      Initialize();

      RANDOMIZE;
      FOR i := 1 TO 10000 DO
        Shuffle();

      Save(Name);
    END;

    PROCEDURE Load@5(Name@1000 : Text[250]);
    VAR
      F@1001 : File;
      i@1002 : Integer;
      c@1003 : Char;
    BEGIN
      F.TEXTMODE := FALSE;
      F.WRITEMODE := TRUE;
      F.OPEN(Name);
      FOR i := 1 TO 256 DO BEGIN
        F.READ(c);
        Cards[i] := c;
      END;
      F.CLOSE;
    END;

    PROCEDURE Code@6(pStrCards@1007 : Text[250];pStrSource@1000 : Text[250];pStrTarget@1006 : Text[250]);
    VAR
      inf@1001 : File;
      c@1002 : Char;
      i@1003 : Integer;
      outf@1004 : File;
      p@1005 : Integer;
    BEGIN
      CreateCards(pStrCards);

      inf.TEXTMODE := FALSE;
      inf.OPEN(pStrSource);

      outf.TEXTMODE := FALSE;
      outf.WRITEMODE := TRUE;
      outf.CREATE(pStrTarget);

      p := 13;
      WHILE inf.LEN <> inf.POS DO BEGIN
        inf.READ(c);
        i := c + Cards[p];
        IF i > 255 THEN
          i := i - 256;
        c := i;
        outf.WRITE(c);
        p := (255 MOD (p + inf.POS)) + 1;
      END;

      outf.CLOSE;
      inf.CLOSE;
    END;

    PROCEDURE Decode@7(pStrCards@1007 : Text[250];pStrSource@1006 : Text[250];pStrTarget@1005 : Text[250]);
    VAR
      inf@1004 : File;
      c@1003 : Char;
      i@1002 : Integer;
      outf@1001 : File;
      p@1000 : Integer;
    BEGIN
      Load(pStrCards);

      inf.TEXTMODE := FALSE;
      inf.OPEN(pStrSource);

      outf.TEXTMODE := FALSE;
      outf.WRITEMODE := TRUE;
      outf.CREATE(pStrTarget);

      p := 13;
      WHILE inf.LEN <> inf.POS DO BEGIN
        inf.READ(c);
        i := c;
        IF i < Cards[p] THEN
          i := i + 256;
        c := i - Cards[p];
        outf.WRITE(c);
        p := (255 MOD (p + inf.POS)) + 1;
      END;

      outf.CLOSE;
      inf.CLOSE;
    END;

    BEGIN
    END.
  }
}