Ask HN: Trusted Computing, iPhone, and unique identifiers

3 pointsbuggy_code16y ago3 comments

Here's the problem:

I'm building an iPhone app. It talks to a server. I want each iPhone to only be able to have _one_ account on the server -- I don't want people creating lots of separate accounts and having them collude.

Now, my iPhone app and my server are talking to each other over TCP/IP. In theory, anyone can build a computer program that fakes the protocol my iPhone app uses (not very hard -- just download the app, log the packets, reverse engineer the API; I can encrypt my traffic, but they can run the app under a VM / extract the key).

So, although I'm generally not a big fan of Trusted Computing -- does the iPhone support anything like this? Where my server can remotely detect "is this device an iPhone?" + "give me a non-forgable UUID" (even if I force the device to be an iPhone, the attacker can still create another iPhone app and have it talk via the same API).

Thanks!

(Sorry: I realize the business man in me says "err, build the product first, worry about this later"; but I'm kind of curious -- both from a technical perspective and a design perspective -- if I know that creating each account requires purchasing an iPhone / iPod touch, I can know up front that people are less likely to create silly accounts & try to screw around).

3 comments

Zev16y ago

  NSString *UUID = [[UIDevice currentDevice] uniqueIdentifier];

Will give you the current devices UUID. And, is it really important to know if the device is an iPod or an iPhone?

However, this won't stop people from screwing around with your app still. If people want to act silly and stupid, they will.

credo16y ago

no, the iPhone doesn't provide a "non-forgable UUID" The [UIDevice currentDevice] uniqueIdentifier isn't going to work because it is trivial to spoof the deviceIdentifier.

You could potentially design your own authentication mechanism and implement the appropriate client-code and server-code to verify (over ssl) that the server request really came from the client that you implemented and from a valid user/subscriber. If your client-code can only run on the iPhone, that may be sufficient to prove that the client is an iPhone and that the user is a valid subscriber.

Travis16y ago

What kind of app are you building that this is a concern?

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