How to delete Keychain data when app is uninstalled?

Question

I have a problem . I am saving some critical information on device Keychain for my App, but when I uninstall the App and install it again, these data is still saved. How can delete these information when the application is uninstalled? If this is not possible, how detect when the App is first Load after install it without save information in NSUserDefaults?

Thank you very much.

Why don't you want to use NSUserDefaults to store whether or not your application is started for the first time? — tilo, Jan 03 '14 at 13:00
you cannot do anything when the application is removed from the device, the application won't be notified about that event. — holex, Jan 03 '14 at 13:03
Because I am saving critical information and I don't want that someone can edit the preferences plist with any program as iExplorer. If someone change any value the consequences could be very bad — Paolpa, Jan 03 '14 at 13:04
@Paolpa, in that case, you should use some encryption then... e.g. _AES256_ is good enough to protect your critical information. — holex, Jan 03 '14 at 13:06
@Paolpa, you problem is here not the safety, your original problem was about you want to delete information when the application is deleted/uninstalled; which is not possible. — holex, Jan 03 '14 at 13:18

score 5 · Answer 1 · edited Jan 03 '14 at 13:27

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This is work around , but may be will satisfy you: Store in NSUserDefaults flag, that keychain have data. If it's NO then ignore keychain.

edited Jan 03 '14 at 13:27

Shaik Riyaz

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answered Jan 03 '14 at 13:16

Cy-4AH

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You should not use NSUserDefaults for sensitive data like passwords or certificates. – orkoden Mar 03 '14 at 13:41
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@orkoden, anybody have said about storing passwords in NSUserDefaults? I am not. – Cy-4AH Mar 03 '14 at 13:46
@ta.speot.is. Thank you cap. Why -1? – Cy-4AH Oct 30 '14 at 10:07
@ta.speot.is, Have you minused answer in http://stackoverflow.com/questions/4747404/delete-keychain-items-when-an-app-is-uninstalled? It's the same, but shorter. – Cy-4AH Oct 30 '14 at 10:23
Sorry, I misread your answer. I can't take back my downvote because I downvoted you a few hours ago, but if you make a small edit to your answer I can upvote it. – ta.speot.is Oct 30 '14 at 10:26
I disagree to save critical information in UserDefaults. – ChuckZHB Aug 09 '21 at 06:57

Jeffery Thomas · Answer 2 · 2014-01-03T13:32:09.767

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I'm not sure why you would not want to use NSUserDefaults. It seems ideal for this purpose.

Barring NSUserDefaults, you could write a file to the Documents directory and use the existence of this file as your flag.

I think I misunderstood your question. I assume the whole time you would use the keychain to store the secure value.

Use a flag in NSUserDefaults to signal that you need to delete the keychain on first launch.

As a real alternative to Keychain, use the Data Protection entitlement.

edited Jan 03 '14 at 13:32

answered Jan 03 '14 at 13:02

Jeffery Thomas

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`NSUserDefault` are not secure, it makes more sense to store it in a more save place like he `KeyChain` since the `NSUserDefault` are just stored as plain text. – rckoenes Jan 03 '14 at 13:05
@rckoenes I updated my answer. I think you want to use Data Protection. – Jeffery Thomas Jan 03 '14 at 13:24
Thank you Jeffery Thomas, very good alternative! – Paolpa Jan 14 '14 at 15:55

How to delete Keychain data when app is uninstalled?

2 Answers2