Cryptocurrency (abbreviated 'crypto') is made possible by cryptography (also abbreviated 'crypto', but few call it that nowadays). Cryptography is from the Greek for secret because it involves doing various things with 'secret keys'. What you use it for may or may not involve secrecy - here are just a few of the most prominent examples:

- Authentication to prove your identity (no secrecy)

- Encryption to keep information private except to certain keyholders (secrecy)

- Signing to prove that information is as originally published (no secrecy)