Sub DecryptText(strText As String, strPwd As String, CaseSensitive as Boolean) as string
Dim i As Integer, c As Integer
Dim strBuff As String
dim ascPwdValue as integer
For i = 1 To Len(strText)
  c = Asc(Mid(strText, i))
  ascpwdvalue=Asc(MidB(strPwd, (i Mod LenB(strPwd)) + 1))
  c = c -ascPwdValue
  strBuff = strBuff + Chr(Bitwise.BitAnd(c, &HFF))
Next i
return strBuff
End sub

Sub EncryptText(strText As String, strPwd As String, CaseSensitive as Boolean) as string
Dim i As Integer, c As Integer
Dim strBuff As String
if CaseSensitive=False then strPwd = Uppercase(strPwd)
If Len(strPwd)>0 Then
  For i = 1 To Len(strText)
    c = Asc(Mid(strText, i, 1))
    c = c + Asc(Mid(strPwd, (i Mod Len(strPwd)) + 1, 1))
    strBuff = strBuff + Chr(BitwiseAnd(c,&HFF))
  Next i
  End If
Return  strBuff
end sub

per criptare
testo =EncryptText(Stringa,passoword , true)

per decriptare
stringa= DecryptText(testo,password,true)