This work envisions a new encryption primitive for many-to-many paradigms such as group messaging systems. Previously, puncturable encryption (PE) was introduced to provide forward security for asynchronous messaging services. However, existing PE schemes were proposed only for one-to-one communication, and causes a significant overhead for a group messaging system. In fact, the group communication over PE can only be achieved by encrypting a message multiple times for each receiver by the sender’s device, which is usually suitable to restricted resources such as mobile phones or sensor devices. Our new suggested scheme enables to re-encrypt ciphertexts of puncturable encryption by a message server (i.e., a proxy) so that computationally heavy operations are delegated to the server who has more powerful processors and a constant power source. We then proposed a new Puncturable Proxy Re-Encryption (PPRE) scheme. The scheme is inspired by unidirectional proxy re-encryption (UPRE), which achieves forward secrecy through fine-grained revocation of decryption capability by integrating the PE scheme. This paper first presents a forward secure PPRE in the group messaging service. Our scheme is IND-CCA secure under 3-weak Decision Bilinear Diffie-Hellman Inversion assumption.
|Title of host publication||Computer Security – ESORICS 2019 - 24th European Symposium on Research in Computer Security, Proceedings|
|Editors||Kazue Sako, Steve Schneider, Peter Y.A. Ryan|
|Number of pages||19|
|State||Published - 2019|
|Event||24th European Symposium on Research in Computer Security, ESORICS 2019 - Luxembourg, Luxembourg|
Duration: 23 Sep 2019 → 27 Sep 2019
|Name||Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)|
|Conference||24th European Symposium on Research in Computer Security, ESORICS 2019|
|Period||23/09/19 → 27/09/19|
Bibliographical notePublisher Copyright:
© 2019, Springer Nature Switzerland AG.
- CCA security
- Group messaging service
- Proxy Re-Encryption
- Puncturable encryption