We construct our attribute-based system using a mechanism we call fully key-homomorphic encryption which is a public-key system that lets anyone translate a ciphertext encrypted under a public-key x into a ciphertext encrypted under the public-key (f(x),f) of the same plaintext, for any efficiently computable f. We show that this mechanism gives an ABE with short keys. Security is based on the subexponential hardness of the learning with errors problem.
We also present a second (key-policy) ABE, using multilinear maps, with short ciphertexts: an encryption to an attribute vector x is the size of x plus poly(k,d) additional bits. This gives a reusable circuit garbling scheme where the size of the garbled input is short, namely the same as that of the original input, plus a poly(k,d) factor.
Category / Keywords: public-key cryptography / Attribute Based Encryption, ABE, Key-Homomorphic Public Key Encryption, Functional Encryption, arithmetic circuits, selective security, learning with errors, LWE, lattices, Reusable Garbled Circuits, Short Secret Key, Short Ciphertext Original Publication (with major differences): IACR-EUROCRYPT-2014 Date: received 20 May 2014, last revised 3 Jun 2014 Contact author: valerini at stanford edu Available format(s): PDF | BibTeX Citation Version: 20140603:185537 (All versions of this report) Short URL: ia.cr/2014/356