David wants to know if he's secure surfing the internet on his mobile device. Leo says that nothing is unhackable, but LTE is encrypted and very secure. A phone can be hacked, even at the radio level, though. It's also possible for someone to spoof his SIM card. But it's too much work for the average hacker. It would have to be a state level attack in order to accomplish it. Wi-Fi is less secure, and if he's relying on WPA2 or any other Wi-Fi connection, it's possible to hack it. But that's not easy, either. Odds are, there's really not all that much to worry about. The real key is to use a good, strong password of at least seven characters. He should make it with random letters and numbers.