CryptoDB
Circuit ABE with poly(depth, λ)-sized Ciphertexts and Keys from Lattices
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| Conference: | CRYPTO 2024 |
| Abstract: | We present new lattice-based attribute-based encryption (ABE) and laconic function evaluation (LFE) schemes for circuits with *sublinear* ciphertext overhead. For depth $d$ circuits over $\ell$-bit inputs, we obtain * an ABE with ciphertext and secret key size $O(1)$; * a LFE with ciphertext size $\ell + O(1)$ and digest size $O(1)$; * an ABE with public key and ciphertext size $O(\ell^{2/3})$ and secret key size $O(1)$, where $O(\cdot)$ hides $\poly(d,\lambda)$ factors. The first two results achieve almost optimal ciphertext and secret key / digest sizes, up to the $\poly(d)$ dependencies. The security of our schemes relies on $\ell$-succinct LWE, a falsifiable assumption which is implied by evasive LWE. At the core of our results is a new technique for compressing LWE samples $s(A-x \otimes G)$ as well as the matrix $A$. |
BibTeX
@inproceedings{crypto-2024-34133,
title={Circuit ABE with poly(depth, λ)-sized Ciphertexts and Keys from Lattices},
publisher={Springer-Verlag},
author={Hoeteck Wee},
year=2024
}