Lattice-Inspired Broadcast Encryption and Succinct Ciphertext-Policy ABE [article]

Zvika Brakerski, Vinod Vaikuntanathan
2020 IACR Cryptology ePrint Archive  
We propose a candidate ciphertext-policy attribute-based encryption (CP-ABE) scheme for circuits, where the ciphertext size depends only on the depth of the policy circuit (and not its size). This, in particular, gives us a Broadcast Encryption (BE) scheme where the size of the keys and ciphertexts have a poly-logarithmic dependence on the number of users. This goal was previously only known to be achievable assuming ideal multilinear maps (Boneh, Waters and Zhandry, Crypto 2014) or
more » ... hability obfuscation (Boneh and Zhandry, Crypto 2014) and in a concurrent work from generic bilinear groups and the learning with errors (LWE) assumption (Agrawal and Yamada, Eurocrypt 2020). Our construction relies on techniques from lattice-based (and in particular LWE-based) cryptography. We analyze some attempts at cryptanalysis, but we are unable to provide a security proof.
dblp:journals/iacr/BrakerskiV20 fatcat:3vgsdki645ewtevfpl75kon3h4