Chameleon Hash Based Efficiently Updatable Oblivious Key Management
Zhiwei Wang, Longwen Lan, Siu Ming Yiu · IEEE Transactions on Services Computing · 2023
Updatable oblivious key management (UOKM) schemes are considered an important backbone of key management for large storage systems, which allows the key management server to periodically update all its clients’ ciphertexts stored in the remote storage cloud without interacting with the clients. All the encrypted data can only be decrypted by the current key (tag), which ensures security against forward and post compromise. In this paper, we propose two UOKM schemes: the first is public key-based, while the second is identity-based. Compared with Jarecki et al.'s UOKM scheme from oblivious pseudorandom functions, the implementations show that our chameleon hash-based schemes have faster updating processes. Moreover, our identity-based UOKM scheme does require ”heavy” public key certificate management and maintains a secure channel from the key management server to the storage cloud, which greatly enhances security and efficiency. Our proofs show that theunconditional obliviousandsecurityof our schemes are based on the security of chameleon hash functions.