Why does Windows require CTRL+ALT+DEL to Logon?

Has Microsoft ever offered an explanation for why they require CTRL+ALT+DEL to login? (Yes I know you can disable it, but it is still their preferred method.) It seems like at one point I heard that it was for security since you knew nothing else could trap CTRL+ALT+DEL, but I've written programs that trap CTRL+ALT+DEL, and it isn't that difficult, so I am pretty sure that was just a myth, either that or the decision to require CTRL+ALT+DEL is based on a fallacy.

Either way, I am curious if there is an official reason, and if that reason has any actual merit.

Thanks!

Solution 1:

This is the same as this Server Fault question: How does CTRL-ALT-DEL to log in make Windows more secure?.

Here is the accepted answer from there, by Oskar Duveborn:

The Windows (NT) kernel is designed to reserve the notification of this key combination to a single process: Winlogon. So, as long as the Windows installation itself is working as it should - no third party application can respond to this key combination (if it could, it could present a fake logon window and keylog your password ;)