Login German username with Case-insensitive

Example from German username:
Uppercase (Goethestraße) = GOETHESTRASZE or GOETHESTRASSE
Use case:
How keycloak would differentiate between these users and how does it prevent one user getting access to other user account in such cases?

@xgp @dasniko @mbonn @bpedersen2 Please look into this

No need to stress people here by mentions. Especially not after that short amount of time. Think of different timezones and different lifestyles, maybe someone else is still sleeping when you are awake.
I’m pretty sure, all of the mentioned people will read your post and if they are able to help / know an answer, they will post it here.

Back to your issue:
Keycloak handles all usernames lowercase and has no clue of special language spellings. So, SZ will transform with a .toLowerCase() method into sz, and SS into ss. There’s no hint that a ß should be used, as this is only a german written rule, but has no counterpart in any encoding.
Thus, GOETHESTRASZE and GOETHESTRASSE are two different usernames for Keycloak.


Sorry for Tag , Thanks for your quick reply

is keycloak support localization ?

yes, of course. but this doesn’t solve the problem.
localization is for displaying labels, messages, etc. in proper language.
there’s no impact on how data is handled.