Channel-based Encryption for Identity-based Traceability for a Decentralized Network

다국어 초록 (Multilingual Abstract)

In this paper, we propose channel based encryption with identity-based traceability for decentralized networks such as fog/edge networks. In a decentralized network, controlling access to data is difficult as the data are transmitted via multiple other nodes. Particularly, when data is transmitted using a protocol that has multiple legitimate recipients like a publish/subscribe protocol, tracing who has accessed broadcast data is difficult. To resolve this problem, we present a new encryption scheme that enables us to trace the data flow by confirming the identity of the actual recipient. We construct a channel-based encryption scheme tracing the data flow, which is suitable for a publish/subscribe protocol, based on revocable attribute-based encryption (ABE). We, then, set the edge server to preprocess the ciphertext by re-encrypting and partially decrypting the ciphertext for the actual recipient. Prior to our work, revocable attribute-based broadcast encryption (ABE) was used only to revoke users by re-encryption. However, this method only allows us to trace recipients after the ciphertext is re-encrypted. That means that the data before reaching the re-encryption oracle, that is the edge server in our proposed system, can be accessed by other recipients without leaving any trace and this makes tracing the data flow difficult. In our proposed scheme, the ciphertext cannot be decrypted only after it is partially decrypted by the edge server. Therefore, tracing the data flow is possible via the edge server. We provide proof of security using the Decisional Diffie-Hellman assumption in the paper.