Broadcast Encryption
Broadcast encryption lets a sender address a whole set of recipients with a single ciphertext that only the authorized subset can decrypt, with ciphertext size independent of (or only logarithmic in) the number of recipients.
Purpose
It supports efficient one-to-many encryption in content distribution (pay TV, multicast) without encrypting separately per user.
Mechanism
Public-key broadcast encryption (Boneh-Gentry-Waters) achieves ciphertext and private-key sizes sublinear in the total number of users; symmetric broadcast encryption (covering families) uses subset-difference schemes. Revocation excludes users through the ciphertext structure.
Use cases
- Pay-TV content encryption
- Multicast security
- Encrypted content distribution