Do current mobile cellular networks like 3G offer enough security? The article from Info-Security states that

3G encryption cracked in less than two hours.

Could a eavesdropper or man-in-the-middle attack be launched on a mobile device? Should we be using a VPN such as Hotspot Shield?

  • it depends on "enough security" from what threat? I'd say that you shouldn't trust 3G network more than any other public network. so some kind of VPN is a good idea
    – JimiDini
    Commented Jan 6, 2014 at 12:56

1 Answer 1


Remember that a 3G data stream contains both voice and Internet data, and the VPN encrypts only the Internet data. Therefore, your phone conversations would remain unprotected unless you use a service like VOIP. VPNs generally have strong AES-128/256 or similar encryption that will take much more than two hours to breach, therefore greatly increasing your security.

If the encryption is cracked, eavesdropping is most likely possible (think of those hackers looking at open wifi connections to sniff for passwords) and probably is a MITM as well.

However, you should still realise that spending two hours to crack a 3G connection is still quite a long time. Unless there is a specific reason why a person would like access to your phone, it is very unlikely that they will spend the effort to break the signal.

  • Per the referenced article (2010): "...unoptimised implementation on a single PC recovered about 96 key bits in a few minutes, and the complete 128 bit key in less than two hours" - if a 2010 PC using an unoptimized implementation took only 2 hours, then we can safely assume that a 2014 attacker will take significantly less time. An advanced attacker may also be using GPU's, not CPU's, and a well funded attacker has more than one modern processor. Commented Mar 8, 2014 at 7:19

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