A Fully Collusion Resistant Public Key Trace and Revoke Scheme with Dynamic Registration and Revocation

We present a new public key trace and revoke scheme, which is suitable for scenarios where usersneed to join or leave the system frequently. The proposedscheme supports public traceability and dynamic registration and revocation. It is also fully collusion resistantagainst adaptive chosen ciphertext attack, and its provablesecurity is tightly reduced to the Decisional Diffe-Hellman(DDH) assumption in the standard model. No master keyis needed in our scheme, and it allows users to generatepublic/private keys themselves and then submit the public keys to the system. This means that the setup phaseonly involves an authentic channel instead of a secure one.Therefore, our scheme can take advantage of Public key infrastructure (PKI) with Certificate authority (CA) playingthe role of the system center.