A Note On Boneh-Gentry-Waters Broadcast Encryption Scheme and Its Like

TL;DR

This paper clarifies the fundamental difference between encryption and key establishment primitives, emphasizing that Boneh-Gentry-Waters scheme is a key establishment method, not an encryption scheme.

Contribution

It highlights the common confusion between encryption and key establishment, and correctly classifies the Boneh-Gentry-Waters scheme as a key establishment protocol.

Findings

Boneh-Gentry-Waters scheme is a key establishment scheme

Confusion exists between encryption and key establishment primitives

Clarification improves understanding of cryptographic primitives

Abstract

Key establishment is any process whereby a shared secret key becomes available to two or more parties, for subsequent cryptographic use such as symmetric-key encryption. Though it is widely known that the primitive of encryption is different from key establishment, we find some researchers have confused the two primitives. In this note, we shall clarify the fundamental difference between the two primitives, and point out that the Boneh-Gentry-Waters broadcast encryption scheme and its like are key establishment schemes, not encryption schemes.