Apparatus and method for direct anonymous attestation from bilinear maps

A method at an issuer, wherein the method comprises:

• creating a group public/secret key pair for a trusted membership group defined by the issuer;
• verifying that an anonymous hardware device has generated a secret member key component of a secret signature key without disclosure of the secret member key of the anonymous hardware device to the issuer;
• assigning a unique group membership certificate to the anonymous hardware device to render the anonymous hardware device a trusted member device of the trusted membership group, the secret signature key including the secret member key and the group membership certificate of the anonymous hardware device;
• and
• publishing the group public key to enable a verifier to:
• perform a first verification that the anonymous hardware device remains a trusted member device of the trusted membership group according to a secret member key component of the secret signature key of the anonymous hardware device;
• perform a second verification that the anonymous hardware device remains a trusted member device of the trusted membership group according to a rogue key list of revoked member keys received by the verifier, wherein the second verification comprises a determination that the secret member key component of a secret signature key of the anonymous hardware device is cryptographically eliminated as a match to any one of the plurality of revoked member keys in the rogue key list via processing of each key in the revoked key list;
• and
• wherein the first verification and the second verification are to be performed by the verifier without the verifier determining the secret member key or any unique device identification information of the anonymous hardware device to enable a trusted member device to remain anonymous to the verifier.

A method in an anonymous hardware device, wherein the method comprises:

• signing, by the anonymous hardware device, a message received from a verifier, the message signed using a private signature key of the anonymous hardware device;
• transmitting a digitally signed message, including a group digital signature of the anonymous hardware device to the verifier, the verifier to authenticate the group digital signature to verify that the anonymous hardware device is a trusted member device of a trusted membership group by performing the following operations:
• performing a first verification that the anonymous hardware device remains a trusted member device of the trusted membership group according to a private member key component of the private signature key of the anonymous hardware device;
• performing a second verification that the anonymous hardware device remains a trusted member device of the trusted membership group according to a rogue key list of revoked member keys received by the verifier, wherein the second verification comprises a determination that the private member key component of a private signature key of the anonymous hardware device is cryptographically eliminated as a match to any one of the plurality of revoked member keys in the rogue key list via processing of each key in the revoked key list;
• and
• wherein the first verification and the second verification are to be performed by the verifier without the verifier determining the private member key or any unique device identification information of the anonymous hardware device to enable a trusted member device to remain anonymous to the verifier.

An apparatus, comprising:

• a flash memory to store a private signature key assigned to the apparatus by an issuer;
• and
• a trusted platform module (TPM) to sign a message received from a verifier, the message signed using the private signature key and to transmit a digitally signed message including a group digital signature of the apparatus to the verifier, wherein the verifier to authenticate the group digital signature to verify that the anonymous hardware device is a trusted member device of a trusted membership group by performing the following operations responsive to the apparatus transmitting the digitally signed message:
• perform a first verification that the apparatus remains a trusted member device of the trusted membership group according to a private member key component of the private signature key of the apparatus;
• performing a second verification that the apparatus remains a trusted member device of the trusted membership group according to a rogue key list of revoked member keys received by the verifier, wherein the second verification comprises a determination that the private member key component of a private signature key of the apparatus is cryptographically eliminated as a match to any one of the plurality of revoked member keys in the rogue key list via processing of each key in the revoked key list;
• and
• wherein the first verification and the second verification are to be performed by the verifier without the verifier determining the private member key or any unique device identification information of the apparatus to enable a trusted member device to remain anonymous to the verifier.

A system, comprising:

• a verifier platform coupled to a network;
• and
• an anonymous prover platform coupled to the network comprising:
• a bus,
• a processor coupled to the bus,
• a chipset coupled to the bus, including a trusted platform module (TPM), the trusted platform module to sign a message received from the verifier platform, the message signed using a private signature key of the prover platform and to transmit a digitally signed message including a group digital signature of the prover platform to the verifier platform, the verifier platform to authenticate the group digital signature to verify that the anonymous prover platform is a trusted member device of a trusted membership group by performing the following operations;
• the verifier platform to perform a first verification that the prover platform remains a trusted member device of the trusted membership group according to a private member key component of the private signature key of the prover platform;
• the verifier platform to perform a second verification that the prover platform remains a trusted member device of the trusted membership group according to a rogue key list of revoked member keys received by the verifier platform, wherein the second verification comprises a determination that the private member key component of a private signature key of the prover platform is cryptographically eliminated as a match to any one of the plurality of revoked member keys in the rogue key list via processing of each key in the revoked key list and
• wherein the first verification and the second verification are to be performed by the verifier platform without the verifier platform determining the private member key or any unique device identification information of the prover platform to enable a trusted member device to remain anonymous to the verifier platform.