SGX Attestation Verification

SGX Attestation Verification Flow

A SGX-based Gramine service generates a TEE attestation, which is uploaded to a smart contract. Verifiers are required to read and verify the TEE attestation. The verification process typically includes the following steps:

  1. Extract the Attestation: Initially, extract the attestation data from the smart contract.

  2. Parse the Attestation: Parse the extracted attestation data, which usually includes the report body, signature, and signing certificate.

    • Report Body: The main part of the report containing information about the execution environment, such as the security version number, attributes, attribute mask, and measurements.

    • Report Data: The data section of the report, containing user-defined data.

    • Signature: The signature over the report body and report data, used to verify the report's integrity and authenticity.

  3. Verify the Signature: Check the validity of the attestation's signature. This often involves using the public key from the signing certificate to validate the signature.

  4. Certificate Chain Verification: Confirm that the signing certificate's chain of trust is valid and issued by a trusted root certificate.

  5. Report Body Verification: Analyze the information in the report body to ensure it meets the expected criteria, including:

    • MRENCLAVE Verification: Ensure the MRENCLAVE value in the report body matches the expected value to confirm the executed code is as intended.

    • Timestamp: Verify the timestamp of the report to ensure it is current.

    • User Data Verification: If user data is included in the report body, verify that this data meets the expected standards.

Verification fields and methods

  • Signature Verification: Validate the signature using the public key to ensure the attestation has not been tampered with.

  • Certificate Chain Verification: Inspect the certificate chain to ensure the signing certificate is issued by a trusted CA.

  • MRENCLAVE Verification: Compare the MRENCLAVE value in the report body with the expected value to ensure the correct executable code is loaded (to do in version 1).

  • Timestamp: Check the report’s generation time to ensure the information is up to date.

  • User Data: If applicable, verify the user-defined data in the report body.


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