Option Compare Database
Option Explicit
Function Kljuc(KorisnickiBroj As String)
Dim I As Integer
Dim KodS As Integer
Dim DuzinaB As Integer
Dim Str As String

DuzinaB = Len(KorisnickiBroj)
    For I = 1 To DuzinaB
    Str = Mid(KorisnickiBroj, I, 1)
    KodS = Asc(Str) + I
        If KodS > Len(K) Then KodS = KodS - Len(K)
        Kljuc = Kljuc & Mid(K, KodS, 1)
    Next I
End Function