Encryption

Encryption takes readable data, called plaintext, and scrambles it into gibberish called ciphertext. Only someone with the right key can unscramble it. It's what protects your passwords, card payments and private chats.

There are two main styles. With symmetric encryption, the same key locks and unlocks. With asymmetric encryption, there's a pair of keys: a public one anyone can use and a private one only you hold. That key-pair idea is the foundation of crypto wallets, although blockchains mostly use it to sign transactions rather than to hide them. Most blockchain data is public, not encrypted.