An Improved Direct Anonymous Attestation Scheme

DAA (direct anonymous attestation), which not only resolves the bottleneck of the privacy CA (certificate authority), but also realizes anonymous and attestation, is one of the best schemes among all attestation of identity schemes currently. But due to complexity and time-consuming of the original DAA scheme, the application of DAA scheme is hindered largely. A new improved direct anonymous attestation based on the discrete logarithm problem of elliptic curves is presented. The scheme still belongs to ECC(elliptic curve cryptography)-DAA, and the scheme’s process and framework are almost same as those of other schemes. But compared with other schemes, the scheme’s main operations are point addition and scalar multiplication of elliptic curves system, the whole complexity is largely decreased, and the scheme’s key and signature length are much shorter. Meanwhile, the scheme reduces the computational cost of each entity in Join protocol, Sign protocol and Verify algorithm, including TPM (trusted platform module), Host, Issuer, Verifier. It gives a practical solution to ECC-based TPM in protecting the privacy of the TPM. This paper gives a detailed security proof of the proposed scheme in ideal-system/real-system security model which shows that the scheme meets the security requirements of unforgeability, variable anonymity and unlinkability.