We propose two novel generic constructions of UE schemes that are secure in the backward-leak uni-directional key update setting from public key encryption (PKE) schemes: the first one requires a key and message homomorphic PKE scheme and the second one requires a bootstrappable PKE scheme. These PKE can be constructed based on standard assumptions (such as the Decisional Diffie-Hellman and Learning With Errors assumptions). It is in stark contrast to the work of Nishimaki, which uses indistinguishability obfuscations.
Category / Keywords: public-key cryptography / Updatable Encryption, Backward-leak Uni-Directional Key Update, No-Directional Key Update, Standard Assumption Date: received 8 Mar 2022, last revised 17 Mar 2022 Contact author: yao jiang at ntnu no, jiaxin pan at ntnu no Available format(s): PDF | BibTeX Citation Version: 20220317:124313 (All versions of this report) Short URL: ia.cr/2022/324