How to replace LockScreen with your own or make autorun after the regular one?

Question

Android

Learning through practice. I have a good programming experience in general, but in Android so far only at the Hello World level.
There is a real demanded task - ICS 4.0.3, to offer the user to solve a simple problem every time the tablet "wakes up". So that until he answers correctly, he does not get to the launcher. That is, you either need to somehow replace the regular Lockscreen with your own (without a slider, only with answer options buttons), or run your task immediately after unlocking the regular Lockscreen, but so that you can’t bypass it and get to the launcher without entering an answer, or to the regular unlocks.
Googled, read books, manuals, even read this answer here (but without comments, it’s not clear how to add something of your own there).
In general, I will be grateful for the recommendation of the general direction of digging - what is generally possible to do and what is impossible (the impossibility of replacing the lockscreen itself programmatically is googled), and if so, how exactly (in general terms, which API to pull, etc.). P.).
Thank you.

Answer 1

Yeah, I already see such a "question" after installing "evil woodpeckers" from an "unverified source":
"Send an SMS to 100500 to unlock the phone ..."
And if, in essence, everything is described in detail on that link, but to write such things you need a level slightly higher than "hello world". I advise you to practice first "on cats".