> If a keyboard input system provides the former sequence of bytes, but the username is stored in the login infrastructure using the latter sequence of [bytes],

> If a keyboard input system provides the former sequence of bytes, but the username is stored in the login infrastructure using the latter sequence of [bytes], then a naive comparison will not find the user "émollier" in the system. Unicode defines in Annex 15 a few normalization forms as a way to work around this problem. But a correct use of these normalization forms still requires coordination and standardization among all programs accessing the data. ICU could work, but adds an extra dependency, there is also GNU's libunistring.