'''Direct anonymous attestation''' is a Digital_signature scheme which allows anonymous signing. This works by allowing verifiers to verify that a message was signed by an authorized signer without revealing who the specific signer was. This is to be used in relation to a Trusted_platform_module where the module would generate a session key, have the key signed anonymously by an external Certificate_authority, and then present the key to the verifier. If the verifier trusts the CA to only sign session keys from correct TPMs, then the verifier can trust the session key and trust the computer on which the TPM is installed. By using a trusted third party one obtains anonymity against the verifying site. Had one just signed the session key with the secret TPM key, then the site could identify revisiting visitors, something which would lessen their anonymity. ==External links== * E. Brickell, J. Camenisch, and L. Chen: ''Direct anonymous attestation''. In Proceedings of 11th ACM Conference on Computer and Communications Security, ACM Press, 2004. (PDF) {{crypto-stub}} Category:Cryptography