Code

Function Miller_Rabin(ByVal n As Integer) As Boolean
        If n <= 3 Then : Return True
        ElseIf n Mod 2 = 0 Then : Return False
        Else
            Dim k, s, a, d, x As Integer
            k = 3
            d = n - 1

            While d Mod 2 = 0
                d = d / 2
                s += 1
            End While

            For c = 1 To k
                a = Random(2, n - 1)
                x = a ^ d Mod n
                If x = 1 Or x = n - 1 Then GoTo skip
                For r = 1 To s - 1
                    x = x ^ 2 Mod n
                    If x = 1 Then
                        Return False
                        Exit Function
                    Else
                        If x = n - 1 Then
                            GoTo skip
                        Else
                            Return False
                            Exit Function
                        End If
                    End If
                Next
skip:       Next
            Return True
        End If
    End Function

    Function Random(ByVal x As Integer, ByVal n As Integer) As Integer
        Dim a As Integer = Now.Millisecond * Now.Second
skip:
        a = (a ^ 2 + 1) Mod (n + 1)
        If a < x Then
            GoTo skip
        Else
            Return a
        End If
    End Function