What’s the difference between Hash, Encrypt, and Encode?
- Hashing: Like turning your name into a secret code that you can’t turn back. Great for passwords.
- Encryption: Like locking a message in a treasure chest with a key. Only someone with the key can open it.
- Encoding: Like turning a picture into LEGO blocks so a computer can understand it. It’s for reading, not hiding.
Can we guess what a hash says?
Maybe! You can try millions of guesses until you get the same hash. But it’s really, really hard if it’s done right.
What is Symmetric vs Asymmetric encryption?
- Symmetric: One key to lock and unlock. Like sharing a padlock key with a friend.
- Asymmetric: One key to lock (public), another to unlock (private). Like sending someone a locked box only they can open.
What’s Fast Hash vs Slow Hash?
- Fast Hash: Quick! Used for checking files.
- Slow Hash: Takes more time on purpose. Used for passwords to make it harder to crack.
Why do we use Encode?
To turn things (like songs, videos, or words) into 1s and 0s that computers can understand and send.
What’s a perfect hash?
A hash that never has two things with the same result — no “collisions.” Super rare!
What’s load factor in hashing?
It’s like how full a bookshelf is. If it’s too full, we get a bigger shelf (rehashing).
What is SSL/TLS?
It’s how your computer talks secretly with websites. It’s like shaking hands with secret codes so no one can listen in.
Steps:
- Your computer says “hello”
- Website replies with “hello” and its ID card
- You check the ID card
- You send a secret (locked with the site’s key)
- Both sides make a new secret code to talk
- Now you’re safe to chat!
What is a CA (Certificate Authority)?
It’s like a teacher who says “Yes, this ID card is real.” Your computer trusts what the teacher says.
What is a digital signature?
It’s like a secret stamp that proves “I really wrote this!”
What is HMAC?
It’s a stamp + lock combo that checks if the message was changed or faked.
How to store passwords and secret stuff safely?
- Passwords: Hash them — no need to know the real ones.
- Secrets like keys: Encrypt them and hide the key in a safe place.
What’s a DDoS and how do we stop it?
A DDoS is like a huge crowd all shouting at your door so you can’t hear real people.
To stop it:
- Block noisy IP addresses
- Let only a few requests in at a time (rate limit)
- Use special guards (firewalls or CDNs) to help watch the gate.