What is encryption, in simple words?
3 minbeginnerencryptioncryptographybasics
Quick Answer
Encryption takes readable data (plaintext) and scrambles it into unreadable data (ciphertext), using an algorithm and a key. Only someone with the right key can reverse it back to plaintext (decryption). TLS uses encryption so data can travel over the internet without anyone in between reading it.
Detailed Answer
Encryption is a way to hide the meaning of data. It takes normal, readable data — called plaintext — and turns it into scrambled data called ciphertext. Anyone who intercepts the ciphertext without the right key just sees random-looking bytes.
plaintext: "Hello, bank!"
| encrypt with a key
v
ciphertext: "8f3a9c2e1b7d..."
To reverse the process and get the plaintext back, you need a matching key. This step is called decryption.
- Algorithm — the fixed set of math rules used to scramble and unscramble data (for example, AES).
- Key — a secret value fed into the algorithm. The same algorithm with a different key produces different ciphertext.
What encryption does, and doesn't, cover:
- Does — hide the meaning of data from anyone without the key.
- Does not — stop someone from changing the ciphertext. TLS adds a separate hash-based check for that.
- In TLS — this protection is often called "encryption in transit," since it covers data while it moves between your browser and a server.