A note on the Chen–Morrissey–Smart DAA scheme

Direct Anonymous Attestation (DAA) is a cryptographic scheme that enables remote authentication of a platform while preserving the privacy of the user of the platform. The DAA scheme developed by Brickell, Camenisch, and Chen has been adopted by the Trust Computing Group (TCG) for remote anonymous attestation of Trusted Platform Module (TPM). Recently, Chen, Morrissey, and Smart proposed an efficient DAA scheme from bilinear pairing. In this paper, we show that there is a design flaw in the name base option of the proposed CMS-DAA scheme such that a corrupted signer or corrupted host may break the linkability property of the DAA scheme. We also suggest a solution that fixes the flaw.