How do you store MFA recovery codes?
PICTURE THIS: HASH MAP
Key"user_id"
Hashslot 17
Valuethe record
Simple meaning
Hash them like passwords and show once.
WHY — Security instead of guessing?
Why interviewers care about Security:
This is a process
question about Security.
Panels listen for order,
trade-offs, and what you would actually do on a .NET MVC project - not buzzwords.
Stay structured
Name the idea, why it exists, then one short example.
Close cleanly
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1Hash them like passwords
and show once.
- 2Why it exists
Consumed codes invalidate.
- 3Plain text recovery codes
in DB are a breach magnet.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Say this line
“Consumed codes invalidate.”
Break into beats
Consumedcodesinvalidate
Speaking order
29874083374
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Hash them like passwords and show once. Consumed codes invalidate.