2020. 2. 8. 23:46ㆍ카테고리 없음
.Part of thebook series (LNCS, volume 9666) AbstractWe prove that there is no fully black-box construction of collision-resistant hash functions (CRH) from hierarchical identity-based encryption (HIBE) with arbitrary polynomial number of identity levels. To the best of our knowledge this is the first limitation proved for HIBE. As a corollary, we obtain a series of separations that are not directly about HIBE or CRH but are interesting on their own right. Namely, we show that primitives such as IBE and CCA-secure public-key encryption cannot be used in a black-box way to construct fully homomorphic encryption or any primitive that implies CRH in a black-box way.Our proof relies on the reconstruction paradigm of Gennaro and Trevisan (FOCS 2000) and Haitner et al. (FOCS 2007) and extends their techniques for one-way and trapdoor permutations to the setting of HIBE.
A main technical challenge in the proof of our separation stems from the adaptivity of the HIBE adversary who is allowed to obtain keys for different identities before she selects the attacked identity. Our main technical contribution is to develop compression/reconstruction techniques that can be achieved relative to such adaptive attackers.
Hierarchical Identity Sociology
- We present a Hierarchical Identity Based Encryption (HIBE) system where the ciphertext consists of just three group elements and decryption requires only two.
- The concept of identity-based encryption (IBE) was introduced by Shamir in 1984 51. An IBE is a type of public key encryption where the public key can be any binary string.
Toward Hierarchical Identity-based Encryption
May 20, 2005 - We present a Hierarchical Identity Based Encryption (HIBE) system where. An Identity Based Encryption (IBE) system 24, 5 is a public key.