What information is stored by iOS Spell Checker?

Question

I have heard that Apple's spell checker for UITextView maintains some kind of logging of what you type in individual applications. I have a secure application where spell checking is a useful feature, however I don't want new words logged to somewhere outside of my application. Can anyone refer me to an Apple reference document or technical description of what information is captured by spell check, and where it is captured too?

Answer 1

Not sure if this helps much, but you could do spell checking manually with the UITextChecker class which allows setting a list of ignored words:

- (void)setIgnoredWords:(NSArray *)words

More here: https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UITextChecker_Class/Reference/Reference.html

You can also check whether the word has been learned with:

+ (BOOL)hasLearnedWord:(NSString *)word

Answer 2

I don't know definitively, but using fseventer, learning the word "aple" in TextEdit saves that word to ~/Library/Spelling/LocalDictionary. Ignoring a word seems not to modify the filesystem at all, and indeed, if the document is closed and not saved, and a new document with that previously-ignored word is opened, it is no longer ignored. This is consistent with +learnWord: being a class method, and -ignoreWord: being an instance method. So for security, you could probably just never call +learnWord:, and instead have your own backend to persistently/securely store a list of ignored words.