CCA-Secure Traceable Threshold (ID-based) Encryption and Application

A recent work by Boneh, Partap, and Rotem [Crypto'24] introduced the concept of traceable threshold encryption, in that if t or more parties collude to construct a decryption box, which performs decryptions, then at least one party's identity can be traced by making a few black-box queries to the box. This has important applications, e.g., in blockchain mempool privacy, where collusion yields high financial gain through MEVs without any consequence -- the possibility of tracing discourages collusion. Nevertheless, their definitions leave room for exploitation as they only achieve CPA security and do not consider inconsistency in decryption via different participating sets.