System and method for combining user and platform authentication in negotiated channel security protocols
View Patent ↗A security protocol for combining user and platform authentication. The security protocol includes a first handshake phase to issue attestation identity credentials, and a second handshake phase to authenticate based on the attestation identity credentials issued in the first handshake phase. The security protocol also includes a session resumption phase to resume a previous session.
1. A security protocol method comprising:
cryptographically hashing a platform configuration value from a platform configuration register (PCR) in a trusted platform module (TPM) that indicates integrity of an endpoint platform, the platform configuration value representing a configuration state of the endpoint platform that indicates an integrity of the endpoint platform to generate a cryptographic hash of the platform configuration;
generating a master secret by hashing together the cryptographic hash of the platform configuration with a pre-master secret from which the master secret is derived, and data from a stored measurement log that stores configuration state measured values for the endpoint platform;
negotiating a communication channel;
signing the generated master secret with multiple authentication facets of the endpoint, the multiple authentication facets including a user key representing a particular user and a platform key representing the particular endpoint platform to produce a master secret signed with multiple authentication keys to authenticate the endpoint;
authenticating, as part of a bidirectional handshaking protocol exchange, the negotiated communication channel with the signed master secret to establish the negotiated communication channel as a secure channel to achieve late binding of the secure channel to prevent the binding from persisting outside the secure channel, including generating a session key for the communication channel, where the session key is generated from the master secret.
2. The method of claim 1 , wherein a platform private key is bound to the platform configuration using the TPM.
3. The method of claim 2 , wherein the TPM comprises a processor coupled to a protected storage device.
4. The method of claim 1 , wherein cryptographically hashing the platform configuration comprises cryptographically hashing the platform configuration using a secure hashing algorithm.
5. The method of claim 4 , wherein the secure hashing algorithm comprises Secure Hashing Algorithm Version 1.0 (SHA-1).
6. The method of claim 1 , wherein the platform configuration includes multiple identities and the platform key includes one or more platform identity keys.
7. The method of claim 1 , wherein the platform configuration includes multiple identities and the platform key includes each platform configuration identity key.
8. The method of claim 1 , further comprising:
exchanging an explanation of the platform configuration hashes following session key negotiations to finalize the authentication;
verifying, at both endpoints, key exchange messages, certificates and platform configuration data; and
authenticating the session if no problems arise during verification.
9. The method of claim 8 , further comprising halting the authentication session if problems arise during verification.
10. The method of claim 8 , further comprising enabling endpoints to exchange data, wherein each endpoint knows that the platform from the other endpoint has been authenticated using a platform identity that ties to the trusted platform module.
11. A computer readable storage medium having instructions stored thereon, which when executed by a processor, provide for simultaneously authenticating multiple facets of an endpoint by:
cryptographically hashing a platform configuration value from a platform configuration register (PCR) in a trusted platform module (TPM) that indicates integrity of an endpoint platform, the platform configuration value representing a configuration state of the endpoint platform that indicates an integrity of the endpoint platform to generate a cryptographic hash of the platform configuration;
generating a master secret by hashing together the cryptographic hash of the platform configuration with a pre-master secret from which the master secret is derived, and data from a stored measurement log that stores configuration state measured values for the endpoint platform;
negotiating a communication channel;
signing the generated master secret with multiple authentication facets of the endpoint, the multiple authentication facets including a user key representing a particular user and a platform key representing the particular endpoint platform to produce a master secret signed with multiple authentication keys to authenticate the endpoint;
authenticating, as part of a bidirectional handshaking protocol exchange, the negotiated communication channel with the signed master secret to establish the negotiated communication channel as a secure channel to achieve late binding of the secure channel to prevent the binding from persisting outside the secure channel, including generating a session key for the communication channel, where the session key is generated from the master secret.
12. The computer readable storage medium of claim 11 , wherein a platform private key is bound to the platform configuration using the TPM.
13. The computer readable storage medium of claim 12 , wherein the TPM comprises a processor coupled to a protected storage device.
14. The computer readable storage medium of claim 11 , wherein instructions for cryptographically hashing the platform configuration comprises instructions for cryptographically hashing the platform configuration using a secure hashing algorithm.
15. The computer readable storage medium of claim 14 , wherein the secure hashing algorithm comprises Secure Hashing Algorithm Version 1.0 (SHA-1).
16. The computer readable storage medium of claim 11 , wherein the platform configuration includes multiple identities and the platform key includes one or more platform identity keys.
17. The computer readable storage medium of claim 11 , further comprising instructions for:
exchanging an explanation of the platform configuration hashes following session key negotiations to finalize the authentication;
verifying, at both endpoints, key exchange messages, certificates and platform configuration data; and
authenticating the session if no problems arise during verification.
18. The computer readable storage medium of claim 17 , further comprising instructions for halting the authentication session if problems arise during verification.
19. The computer readable storage medium of claim 17 , further comprising instructions for enabling endpoints to exchange data, wherein each endpoint knows that the platform from the other endpoint has been authenticated using a platform identity that ties to the trusted platform module.