Enkripcija transformira podatke u nečitljiv oblik (šifrski tekst) koji se može dešifrirati samo s pravim ključem — čime štiti povjerljivost. Razumijevanje simetrične vs asimetrične enkripcije, te podataka u prijenosu vs podataka u mirovanju, važno je za zaštitu osjetljivih podataka.
Simetrična vs asimetrična enkripcija
SYMMETRIC → ONE shared key encrypts AND decrypts (e.g. AES):
✓ fast, efficient → for bulk data (encrypting files, databases)
✗ both parties need the same key (key distribution is the challenge)
ASYMMETRIC → a KEY PAIR: PUBLIC key (encrypt / verify) + PRIVATE key (decrypt / sign):
→ encrypt with the public key, only the private key decrypts (e.g. RSA, ECC)
✓ solves key distribution (share the public key freely); enables signatures
✗ slower → used for key exchange, signatures, not bulk data
→ Often COMBINED: asymmetric to exchange a symmetric key, then symmetric for the data
(e.g. how TLS works).
