This is a follow up bug from bug 591118, we currently are using lower case letters in the sync key, but this has a few disadvantages: -the sections appear to be malformed words -the key is slightly harder to read -the key isn't as consistent with other forms of activation codes Assuming that these keys are not case sensitive (I believe that was the plan), I don't think users will actually bother to capitalize the text when doing mobile entry. So for readability and to help make this self describing as an activation code, I think we should use the standard style of capital letters.

Here are some examples of physical keys that are becoming increasingly common. In addition to windows activation codes, we also see these with pre-paid cards for various services, always using upper case letters for readability. (also as far as I know these are all still active, in case anyone wants to get into one of these 4 betas :)

I disagree with the assertion that people won't bother capitalizing the key. I think that people will try entering what's in front of them. Entering uppercase keys is *very* painful on mobile keyboards, especially on the iPhone, which has caps lock pref-ed off by default. What heuristics have we implemented to discern a user-selected key from a auto-generated sync key?

(In reply to comment #0) > This is a follow up bug from bug 591118, we currently are using lower case > letters in the sync key, but this has a few disadvantages: > > -the sections appear to be malformed words I don't see how this would change with capital letters. > -the key is slightly harder to read > -the key isn't as consistent with other forms of activation codes > > Assuming that these keys are not case sensitive (I believe that was the plan), They aren't, but I suppose we could make our "sync key detection code" smash case as well (right now it checks for total length of 23 and dashes in the right places). But passphrases in general are case sensitive (see below). > I don't think users will actually bother to capitalize the text when doing > mobile entry. So for readability and to help make this self describing as an > activation code, I think we should use the standard style of capital letters. Well, most activation code systems also tend to automatically uppercase on input to let the user know that case doesn't matter. This would be very difficult to do for us if we still want to support custom passphrases in the same input box (because those *are* case sensitive).

(In reply to comment #0) > -the key is slightly harder to read Actually, this assertion bugs me too. Can you back that up? It's widely accepted that all caps makes text /harder/ to read if you're dealing with natural language. The one study I found on random strings found no difference between uppper and lower case.

I believe the capital letters are primarily used in other keys to differentiate between potentially similar shape of numbers (l, 1) etc. We aren't using numbers, but I in general would like the physical sync key to be as self describing as possible (conjuring thoughts of other similar situations where the user entered a sequence of upper case letters). I wasn't aware that the user created sync keys were case sensitive, that obviously complicates things.

This bug only affects Sync 1.1, and it was shut down in the fall of 2015 (https://blog.mozilla.org/services/2015/07/31/shutting-down-the-legacy-sync-service/).