What's the best way to store data that one iOS app sends to another?

[Richard Gaskin]

John Craig wrote:
> In my case, the user credentials are an app id and a password.  They are
> set up manually, beforehand, to allow any number of app instances
> running on users' devices to connect and share data.
> If you want to create actual user accounts through your app and don't
> want to send plain text then you're going to have to use encryption.

One method Dave Cragg, me, and others have used is a home-grown 
quasi-HTTPS-like scheme in which the client first handshakes with the 
server to obtain a token, which is a hash of the IP address, time stamp, 
and some salt, and that token is used as a key to send the 
authentication data, after which all other data uses a less derivable 
method.

While imperfect, and of course no substitute for just using a cert, it 
keeps the credentials reasonably well protected since hacking it 
requires both spoofing the IP address of the client and doing so within 
a limited time frame.

--
  Richard Gaskin
  Fourth World
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