Abstract
Direct Anonymous Attestation (DAA) is a special type of anonymous digital signatures, used by the Trusted Computing Group (TCG) for the purpose of computer platform attestation whilst preserving platform anonymity. Like any other anonymous cryptographic primitives, how to efficiently revoke an existing member who is no longer legitimate, is an important and challenging subject for DAA. In this paper, we first explain two general DAA revocation approaches and a number of different DAA revocation degrees. We then present a variety of revocation mechanisms, which enable us to achieve these approaches and degrees in the existing three types of DAA schemes. Some of these mechanisms have already been shown in the literature and others are newly proposed in this paper.