Bonsai Trees, or How to Delegate a Lattice Basis

We introduce a new lattice-based cryptographic structure called a bonsai tree, and use it to resolve some important open problems in the area. Applications of bonsai trees include: • An efficient, stateless ‘hash-and-sign’ signature scheme in the standard model (i.e., no random oracles), and • The first hierarchical identity-based encryption (HIBE) scheme (also in the standard model) that does not rely on bilinear pairings. ingly, the abstract properties of bonsai trees seem to have no known realization in conventional number-theoretic cryptography.

• Type: Conference
• Year: 2010
• Where: EUROCRYPT
• Authors: David Cash, Dennis Hofheinz, Eike Kiltz, Chris Peikert
• Keywords: Bonsai Trees, Cryptology, EUROCRYPT 2010, Lattice-based Cryptographic Structure, Standard Model