IBE-Signal: Reshaping Signal into a MITM-Attack-Resistant Protocol

The Signal Protocol is one of the most popular privacy protocols today for protecting Internet chats and supports end-to-end encryption. Nevertheless, despite its many advantages, not resistant to Man-In-The-Middle (MITM) attacks because a malicious server can distribute forged identity-based public keys during user registration phase. To address this problem, we proposed IBE-Signal scheme that replaced Extended Triple Diffie–Hellman (X3DH) key agreement protocol with enhanced Identity-Based Encryption (IBE). Specifically, adoption verifiable parameter initialization ensures authenticity system parameters. At same time, Signature (IBS) enables our support mutual authentication. Moreover, distributed generation mechanism served as risk decentralization mitigate IBE’s escrow problem. Besides, revocable IBE used revocation Notably, IND-ID-CPA security proven under random oracle model. Compared existing schemes, provided new features authentication, perfect forward secrecy, post-compromise security, revocation. Experiments showed computational overhead lower than other schemes when Cloud Privacy Centers (CPCs) number less 8.