EncDec_WYD

unit EncDec_WYD;


interface

Type Enc_Dec = Class
  public
    procedure Encrypt(Src:array of byte; Len:Word);
    function Decrypt(Src:array of byte; Len:Word): boolean;
end;

implementation

Uses Main, MMSystem, SysUtils;

var
EncDecKeys: array[0..511] of Byte =
   ($84, $87, $37, $D7, $EA, $79, $91, $7D, $4B, $4B, $85, $7D, $87, $81, $91, $7C,
    $0F, $73, $91, $91, $87, $7D, $0D, $7D, $86, $8F, $73, $0F, $E1, $DD, $85, $7D,
    $05, $7D, $85, $83, $87, $9C, $85, $33, $0D, $E2, $87, $19, $0F, $79, $85, $86,
    $37, $7D, $D7, $DD, $E9, $7D, $D7, $7D, $85, $79, $05, $7D, $0F, $E1, $87, $7E,
    $23, $87, $F5, $79, $5F, $E3, $4B, $83, $A3, $A2, $AE, $0E, $14, $7D, $DE, $7E,
    $85, $7A, $85, $AF, $CD, $7D, $87, $A5, $87, $7D, $E1, $7D, $88, $7D, $15, $91,
    $23, $7D, $87, $7C, $0D, $7A, $85, $87, $17, $7C, $85, $7D, $AC, $80, $BB, $79,
    $84, $9B, $5B, $A5, $D7, $8F, $05, $0F, $85, $7E, $85, $80, $85, $98, $F5, $9D,
    $A3, $1A, $0D, $19, $87, $7C, $85, $7D, $84, $7D, $85, $7E, $E7, $97, $0D, $0F,
    $85, $7B, $EA, $7D, $AD, $80, $AD, $7D, $B7, $AF, $0D, $7D, $E9, $3D, $85, $7D,
    $87, $B7, $23, $7D, $E7, $B7, $A3, $0C, $87, $7E, $85, $A5, $7D, $76, $35, $B9,
    $0D, $6F, $23, $7D, $87, $9B, $85, $0C, $E1, $A1, $0D, $7F, $87, $7D, $84, $7A,
    $84, $7B, $E1, $86, $E8, $6F, $D1, $79, $85, $19, $53, $95, $C3, $47, $19, $7D,
    $E7, $0C, $37, $7C, $23, $7D, $85, $7D, $4B, $79, $21, $A5, $87, $7D, $19, $7D,
    $0D, $7D, $15, $91, $23, $7D, $87, $7C, $85, $7A, $85, $AF, $CD, $7D, $87, $7D,
    $E9, $3D, $85, $7D, $15, $79, $85, $7D, $C1, $7B, $EA, $7D, $B7, $7D, $85, $7D,
    $85, $7D, $0D, $7D, $E9, $73, $85, $79, $05, $7D, $D7, $7D, $85, $E1, $B9, $E1,
    $0F, $65, $85, $86, $2D, $7D, $D7, $DD, $A3, $8E, $E6, $7D, $DE, $7E, $AE, $0E,
    $0F, $E1, $89, $7E, $23, $7D, $F5, $79, $23, $E1, $4B, $83, $0C, $0F, $85, $7B,
    $85, $7E, $8F, $80, $85, $98, $F5, $7A, $85, $1A, $0D, $E1, $0F, $7C, $89, $0C,
    $85, $0B, $23, $69, $87, $7B, $23, $0C, $1F, $B7, $21, $7A, $88, $7E, $8F, $A5,
    $7D, $80, $B7, $B9, $18, $BF, $4B, $19, $85, $A5, $91, $80, $87, $81, $87, $7C,
    $0F, $73, $91, $91, $84, $87, $37, $D7, $86, $79, $E1, $DD, $85, $7A, $73, $9B,
    $05, $7D, $0D, $83, $87, $9C, $85, $33, $87, $7D, $85, $0F, $87, $7D, $0D, $7D,
    $F6, $7E, $87, $7D, $88, $19, $89, $F5, $D1, $DD, $85, $7D, $8B, $C3, $EA, $7A,
    $D7, $B0, $0D, $7D, $87, $A5, $87, $7C, $73, $7E, $7D, $86, $87, $23, $85, $10,
    $D7, $DF, $ED, $A5, $E1, $7A, $85, $23, $EA, $7E, $85, $98, $AD, $79, $86, $7D,
    $85, $7D, $D7, $7D, $E1, $7A, $F5, $7D, $85, $B0, $2B, $37, $E1, $7A, $87, $79,
    $84, $7D, $73, $73, $87, $7D, $23, $7D, $E9, $7D, $85, $7E, $02, $7D, $DD, $2D,
    $87, $79, $E7, $79, $AD, $7C, $23, $DA, $87, $0D, $0D, $7B, $E7, $79, $9B, $7D,
    $D7, $8F, $05, $7D, $0D, $34, $8F, $7D, $AD, $87, $E9, $7C, $85, $80, $85, $79,
    $8A, $C3, $E7, $A5, $E8, $6B, $0D, $74, $10, $73, $33, $17, $0D, $37, $21, $19);

procedure Enc_Dec.Encrypt(Src:array of byte; Len:Word);
var i:Cardinal;
pos,key,rand_key: integer;
sum1,sum2: integer;
begin
   sum1:=0;
   sum2:=0;
   Randomize;
   rand_key := Random(255);
   BufferDest[0]:=WordRec(Len).Lo;
   BufferDest[1]:=WordRec(Len).Hi;
   BufferDest[2]:=rand_key;
   BufferDest[3]:=0;
   Src[8]:=timegettime;

   pos:=EncDecKeys[rand_key * 2];
   i:=4;

   while( i < Len) do begin
    key := EncDecKeys[((pos and $FF) * 2) + 1];
    case (i and 3) of
    0:
    begin
      key := key * 2;
      key := Key and 255;
      BufferDest[i] := Src[i] + key;
    end;
    1:
    begin
      key := key shr 3;
      key := Key and 255;
      BufferDest[i] := Src[i] - key;
    end;
    2:
    begin
      key := key * 4;
      key := Key and 255;
      BufferDest[i] := Src[i] + key;
    end;
    3:
    begin
      key := key shr 5;
      key := Key and 255;
      BufferDest[i] := Src[i] - key;
    end;
    else
    begin
      key := key shr 5;
      key := Key and 255;
      BufferDest[i] := Src[i] - key;
    end;
    end;
    sum1:=sum1+Src[i];
    sum2:=sum2+BufferDest[i];
    inc(pos,1);
    inc(i,1);
   end;
   sum1:= sum1 and $FF;
   sum2:= sum2 and $FF;
   BufferDest[3] := ((sum2 - sum1) and 255);
end;

function Enc_Dec.Decrypt(Src:array of byte; Len:Word): boolean;
var i:Cardinal;
pos,key: integer;
sum1,sum2: integer;
begin
   sum1:=0;
   sum2:=0;

   pos:=EncDecKeys[Src[2] * 2];
   i:=4;

   while(i < Len) do begin

    sum1:=sum1 + Src[i];
    key := EncDecKeys[((pos and $FF) * 2) + 1];

    case (i and 3) of
    0:
    begin
      key := key shl 1;
      key := Key and 255;
      Src[i] := Src[i] - key;
    end;
    1:
    begin
      key := key shr 3;
      key := Key and 255;
      Src[i] := Src[i] + key;
    end;
    2:
    begin
      key := key shl 2;
      key := Key and 255;
      Src[i] := Src[i] - key;
    end;
    3:
    begin
      key := key shr 5;
      key := Key and 255;
      Src[i] := Src[i] + key;
    end;
    else
    begin
      key := key shr 5;
      key := Key and 255;
      Src[i] := Src[i] + key;
    end;
    end;

    sum2:=sum2+Src[i];
    inc(pos,1);
    inc(i,1);
   end;
   sum1:= sum1 and 255;
   sum2:= sum2 and 255;
   Move(Src,BufferDest,sizeof(Src));
   if Src[3] <> ((sum2 - sum1) and 255) then
   result:=false
   else
   result:=true;
end;

end.