'Coded by S.Boukas'
'rc4 encryption complete program'
     $APPTYPE GUI
     $INCLUDE "rapidq.inc"
     DECLARE SUB CoolBtn1Click (Sender AS QCOOLBTN)
     DECLARE SUB Button1Click (Sender AS QBUTTON)
     DIM filename AS STRING
     DIM f$ AS STRING
     DIM b AS BYTE
     DIM opendialog AS QOPENDIALOG
     DIM file1 AS QFILESTREAM
     DIM file2 AS QMEMORYSTREAM
     CREATE Form AS QFORM
      Caption = "Padlock v1.0..."
      Width = 271
      Height = 139
      Center
      CREATE CoolBtn1 AS QCOOLBTN
       Caption = "..."
       Left = 230
       Top = 15
       Width = 23
       Height = 22
       onclick=coolbtn1click
      END CREATE
      CREATE Edit1 AS QEDIT
       Text = "Keyphrase"
       Left = 11
       Top = 15
       Width = 217
      END CREATE
      CREATE ListBox1 AS QLISTBOX
       Left = 11
       Top = 44
       Width = 217
       Height = 21
       TabOrder = 1
      END CREATE
      CREATE Button1 AS QBUTTON
       Caption = "Crypt"
       Left = 179
       Top = 77
       Width = 51
       TabOrder = 2
       onclick=button1click
      END CREATE
     END CREATE


     DIM s(0 to 255)
     DIM k(0 to 255)


     Form.ShowModal



     SUB CoolBtn1Click (Sender AS QCOOLBTN)
   '-- Enter your code here
      listbox1.clear
      IF opendialog.execute THEN
       f$=opendialog.filename
       listbox1.additems f$
      END IF

     END SUB


      SUB Button1Click (Sender AS QBUTTON)

      IF f$="" THEN SHOWMESSAGE("Please select file !")
      k$=edit1.text
      IF k$="" THEN SHOWMESSAGE("Please select a keyphrase !")
      GOSUB keygen
      file1.open(f$,fmopenread)
      i=0
      j=0
      aa:
      IF file1.eof=-1 THEN file1.close:GOTO cc
      file1.read(b)
      i=(i+1)MOD 256
      j=(j+s(i))MOD 256
      swap s(i),s(j)
      t=(s(i)+(s(j)MOD 256))MOD 256
      y=s(t)
      c=y XOR b
      c$=CHR$(c)
      file2.write(c$)
      GOTO aa
      cc:
      file1.open(f$,fmcreate)
      file1.copyfrom(file2,0)
      file1.close
      file2.close
      SHOWMESSAGE("file processed !"):GOTO dd:
      keygen:
      FOR i=0 TO 255
       s(i)=i
      NEXT i
      j=1
      FOR i=0 TO 255
       IF j>LEN(k$) THEN j=1
       k(i)=ASC(MID$(k$,j,1))
       j=j+1
      NEXT i
      j=0
      FOR i=0 TO 255
       j=(j+s(i)+k(i))MOD 256
       swap s(i),s(j)
       NEXT i
      RETURN
     dd:
     END SUB