Private Function test9() As Long
Dim a As Long, c As Long, b As Long, i As Long, b_i As Long, res As Long, m As _
  Long
 
    'res = a ^ c Mod m
    ' 27 = 48^37 Mod 77
    ' 48 = 27^13 Mod 77
 
    'Versuchsreihe:   
    'A)          'B)   'C)            'D)     'E)    'F)  
    a = 48       '27   '15633         '2      '3     '5
    c = 37       '13   '1373          '11     '4     '9
    b = 100101   '1101 '10101011101   '1011   '100   '1001
    m = 77       '77   '263713        'ohne   'ohne  'ohne
 
    res = 1
    i = 0
    For i = 1 To Len(b)
        b_i = Mid(b, i, 1)
        res = res ^ 2 Mod m        'bei ohne m nur Mod m auskommentieren
        If b_i = 1 Then
            res = (res * a) Mod m  'bei ohne m nur Mod m auskommentieren
        End If
    Next i
    'Debug.Print res
    MsgBox res
 
End Function