ABE for Circuits with poly\( {(\lambda )}\)-Sized Keys from LWE
Valerio Cini, Hoeteck Wee · SIAM Journal on Computing · 2025
Abstract. We present a key-policy attribute-based encryption (ABE) scheme for circuits based on the Learning with Errors (LWE) assumption, whose key size is independent of the circuit depth. Our result constitutes the first improvement for ABE for circuits from LWE in almost a decade, given by Gorbunov, Vaikuntanathan, and Wee ( Attribute-based encryption for circuits, 2013) and Boneh et al. ( Fully key-homomorphic encryption, arithmetic circuit ABE and compact garbled circuits, 2014): We reduce the key size in the latter from [Formula: see text] to [Formula: see text]. The starting point of our construction is a recent ABE scheme of Li, Lin, and Luo ( ABE for circuits with constant-size secret keys and adaptive security, 2022) which achieves [Formula: see text] key size but requires pairings and generic bilinear groups in addition to LWE; we introduce new lattice techniques to eliminate the additional requirements.