Succinct and Adaptively Secure ABE for ABP from k-Lin

摘要

We present succinct and adaptively secure attribute-based encryption (ABE) schemes for arithmetic branching programs, based on k-Lin in pairing groups. Our key-policy ABE scheme has ciphertexts of constant size, independent of the length of the attributes, and our ciphertext-policy ABE scheme has secret keys of constant size. Our schemes improve upon the recent succinct ABE schemes in [Tomida and Attrapadung, ePrint '20], which only handles Boolean formulae. All other prior succinct ABE schemes either achieve only selective security or rely on q-type assumptions. Our schemes are obtained through a general and modular approach that combines a public-key inner product functional encryption satisfying a new security notion called gradual simulation security and an information-theoretic randomized encoding scheme called arithmetic key garbling scheme.