Public Function IsValidCPF(ByVal strCPF As String) As Boolean

Option Explicit
 
Public Function IsValidCPF(ByVal strCPF As String) As Boolean
    Dim intDigito As Integer
    Dim intIndex As Integer
    Dim intModulo As Integer
    Dim intSoma1 As Integer
    Dim intSoma2 As Integer
    Dim intDigitoVerificador1 As Integer
    Dim intDigitoVerificador2 As Integer
 
    intSoma1 = 0
    intSoma2 = 0
 
    For intIndex = 1 To 9
        intDigito = CInt(Mid$(strCPF, intIndex, 1))
        intSoma1 = intSoma1 + ((11 - intIndex) * intDigito)
        intSoma2 = intSoma2 + ((12 - intIndex) * intDigito)
    Next
 
    intModulo = intSoma1 Mod 11
    If intModulo < 2 Then
        intDigitoVerificador1 = 0
    Else
        intDigitoVerificador1 = 11 - intModulo
    End If
 
    intSoma2 = intSoma2 + (2 * intDigitoVerificador1)
 
    intModulo = intSoma2 Mod 11
    If intModulo < 2 Then
        intDigitoVerificador2 = 0
    Else
        intDigitoVerificador2 = 11 - intModulo
    End If
 
    IsValidCPF = ( _
                  (Mid$(strCPF, 10, 1) = CStr(intDigitoVerificador1)) And _
                  (Mid$(strCPF, 11, 1) = CStr(intDigitoVerificador2)) _
                 )
End Function