Il existe plusieurs facon d'avoir son IP
la premiere que j'aime bien c'est le WMI, 2 autres avec System.Net et peut et d'aure que je ne connais pas forcement

Pour le code donné en WMI 

   Imports System.Management

     Public Sub AdresseIPWmi()
        Dim query As ManagementObjectSearcher = New _
            ManagementObjectSearcher("SELECT * FROM WIN32_NetworkAdapterConfiguration WHERE IPEnabled = 'TRUE'")
        Dim queryCollection As ManagementObjectCollection = query.Get()
        Dim mo As ManagementObject
        For Each mo In queryCollection
            Dim addresses() As String = CType(mo("IPAddress"), String())
            Dim defaultgateways() As String = CType(mo("DefaultIPGateway"), String())

            Console.WriteLine("Network Card: {0}", mo("Description"))
            Console.WriteLine("MAC Address: {0}", mo("MACAddress"))
            Dim ipaddress As String
            For Each ipaddress In addresses
                Console.WriteLine("IP Address: {0}", ipaddress)
            Next
            Dim gateway As String
            For Each gateway In defaultgateways
                Console.WriteLine("Gateway: {0}", gateway)
            Next
        Next
    End Sub

Les Imports puis ajouter une référence System.Security

Imports System.Security.Cryptography
Imports System.Text

 La fonction de Cryptage

Public Function Cryptage(ByVal StrCryptage As String)
Dim ConvertBytes() As Byte = Encoding.Default.GetBytes(StrCryptage)
Dim CryptData() As Byte = ProtectedData.Protect(ConvertBytes, Nothing, DataProtectionScope.CurrentUser)
Dim s As String = Convert.ToBase64String(CryptData)
Return s
End Function