title: Signed request from iOS device to web service
body: <p>We're looking to use the UDID to authenticate a user against server-side web services for an iOS application. My one concern is that users will try to brute force access to another user's account by making auth attempts using random UDID values. I can work on things such as throttling their requests, however I was curious if there is a way to make a "signed" request.</p>
  
  <p>Meaning, is there a way I can certify that the client with UDID foo was generated and sent from the device that UDID foo belongs to, and not some random user with access to curl and a ruby script to call my service multiple times?</p>
  
  <p>I think what I'm looking for is a signed http request. I'm not sure where to start building out such support on either the client or server though. </p>