Как зашифровать строку, выполнив циклическую замену каждой буквы на следующую за ней в алфавите

Option Explicit
Option Compare Text
Private Sub Form_Load()
    Dim i As Long, s As String
    s = InputBox("Введите строку")
    For i = 1 To Len(s)
        Select Case Mid$(s, i, 1)
        Case "а" To "ю": Mid$(s, i, 1) = Chr$(Asc(Mid$(s, i, 1)) + 1)
        Case "я": Mid$(s, i, 1) = "а"
        End Select
    Next
    MsgBox s
End Sub

Option Explicit
'''Option Compare Text'''
 
Private Sub Form_Load()
    Dim i As Long, s As String
    s = InputBox("Введите строку")
    For i = 1 To Len(s)
        Select Case Mid$(s, i, 1)
        Case "А"to"Ю","а" To "ю": Mid$(s, i, 1) = Chr$(Asc(Mid$(s, i, 1)) + 1)
        Case "я": Mid$(s, i, 1) = "а"
        Case "Я": Mid$(s, i, 1) = "А"
        End Select
    Next
    MsgBox s
End Sub

Option Compare Text'!!!
 
Sub Form_Load()
    Dim i As Long, s As String
    s = InputBox("Введите строку")
    For i = 1 To Len(s)
        Select Case Mid$(s, i, 1)
        Case "А" To "Я": Mid$(s, i, 1) = Chr$((Asc(Mid$(s, i, 1)) + 1) Mod 32 + (Asc(Mid$(s, i, 1)) \ 32) * 32)
        End Select
    Next
    MsgBox s
End Sub