[.NET] [VB] Ganz einfaches Ver- und Entschlüsselungsverfahren

Public Class xxx

 Private Enum CryptMode As Integer
 Encode = 0
 Decode = 1
 End Enum

 Private Function Crypt(ByVal input As String, ByVal key As String, ByVal cryptMode As CryptMode) As String

 Dim result, cptString As String
 Dim i, position As Integer
 Dim cptZahl, orgZahl, keyZahl As Long


 For i = 1 To Len(input)
 position = position + 1
 If position > Len(key) Then position = 1
 keyZahl = Asc(Mid(key, position, 1))

 Select Case cryptMode
 Case cryptMode.Encode
 orgZahl = Asc(Mid(input, i, 1))
 cptZahl = orgZahl Xor keyZahl
 cptString = Hex(cptZahl)
 If Len(cptString) < 2 Then cptString = "0" & cptString
 result &= cptString
 Case cryptMode.Decode
 If i > Len(input) \ 2 Then Exit For
 cptZahl = CByte("&H" & Mid$(input, i * 2 - 1, 2))
 orgZahl = cptZahl Xor keyZahl
 result &= Chr(CInt(orgZahl))
 End Select

 Next i

 Return result
 End Function

End Class