I have been asked my my UDID to beta test apps, is there personal information attached to this number? Such as passwords or account information?

Details about the device, I am running ios7.1 on an ipad 2.

1 Answer 1


Your UDID can be used to uniquely identify your iOS device. The UDID is often used to associate actions with a specific known user. Using your UDID, developers' may be able to associate your actions and use of their app back to you.

Apple associate private information with your UDID. You are required to trust that Apple keeps this information private. Hopefully Apple will not sell this information or have it leaked through a security breach. While not highly valuable, if you have privacy concerns consider avoiding participating in beta apps programs.

ArsTechnica has a useful article that discusses the relative risks and uses of the UDID, Ask Ars: What’s the big deal with iPhone UDIDs?

  • What are your thoughts on past tense vs present tense for this answer/UDID? Apple clearly changed the availability of UDID to all developers and iOS no longer provides unique values to apps (save Apple's own apps). Third parties now have to ask the end user for it as opposed to massively collecting all user UDID on first run of an app as old iOS allowed.
    – bmike
    Commented Mar 17, 2014 at 11:29
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    In the context of being actively asked, we should be aware that this will likely provide a means of associating known device UDIDs to an individual; be that through sanctioned APIs, security flaws, or when running on pre-iOS 7 devices. We have to trust Apple but we can choose not to actively disclose this information to others. Clearly Apple feel UDIDs are sensitive information; their changes in iOS 7 reflect this believe. Privacy is a tricky and personal subject. Commented Mar 17, 2014 at 11:42
  • I don't see the possibility of a problem - could you walk me through any one way a malicious developer would harm my identity or personal information if they got the UDID of my iPhone 5 running iOS 7.
    – bmike
    Commented Mar 17, 2014 at 17:45
  • @bmike that is kind of what I was looking for. If someone gets a hold of my UDID can they say access information from an other app on the device or just the information that they receive from their app.
    – Ronit
    Commented Mar 18, 2014 at 7:02
  • @Ronit consider the UDID as a key or index into a database. Much like your social security number or passport number, the UDID is not intrinsically valuable on its own. However combined with other information it becomes valuable. Apple took steps to further add protection around the UDID in iOS 7, so you may want to consider carefully before proactively sharing it manually with others. Commented Mar 18, 2014 at 9:16

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