Encryption
Encryption scrambles data so only key holders can read it.
About this topic
Encryption scrambles data so only someone with the right key can read it. The original message is plaintext, the scrambled form is ciphertext, and an algorithm called a cipher does the conversion. Symmetric encryption, such as AES, uses the same key to encrypt and decrypt, which is fast but requires sharing the key safely. Asymmetric encryption uses a public key to encrypt and a private key to decrypt, which solves the key sharing problem.
RSA is a well-known asymmetric method based on the difficulty of factoring very large numbers. In practice, HTTPS uses asymmetric methods to agree on a symmetric key, then uses the fast symmetric method for the rest of the session. Digital signatures use private keys to prove who sent a message. Encryption protects messages, online banking, stored files and wireless networks.
A common misconception is that encryption makes something completely unbreakable; weak keys, bad passwords or poor implementations can still be attacked. Another is mixing encryption with hashing: encryption can be reversed with a key, hashing cannot. Governments and companies debate whether to allow access to encrypted data, balancing privacy with security. Always use well-tested standards instead of inventing your own.
Key ideas
- Symmetric vs public-key
- HTTPS uses TLS
- Caesar cipher is a simple example
Quick check
Use cases: where Encryption helps
- Homework: review the key idea behind Encryption before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Encryption without notes.
- Visual learning: play with the interactive lab to see how Encryption changes when you adjust its inputs.
- Teaching a friend: explain Encryption in your own words, then compare your version with the key ideas.
Computing ideas run phones, search engines, games and the wider internet.
Frequently asked questions
What is Encryption?
Encryption scrambles data so only key holders can read it.
What will I learn in Encryption?
Symmetric vs public-key. HTTPS uses TLS. Caesar cipher is a simple example.
Is Encryption part of Computer Science?
Yes. It is one of 80 Computer Science topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Encryption lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Encryption?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.