Enclave Measurement

A 256-bit cryptographic hash representing the exact identity of the code, initial data, and configuration loaded into an Intel SGX enclave. It is the most granular measurement, changing with any code modification.

• Computed over the enclave's initial memory layout and metadata
• Serves as a unique, unforgeable fingerprint for a specific software version
• Used in attestation to verify that the expected binary is running
• A change in even a single line of source code results in a completely different MRENCLAVE value

A cryptographic hash of the public key used to sign an enclave's authorizing certificate. Unlike MRENCLAVE, MRSIGNER identifies the software vendor rather than a specific code version.

• Allows trust to be established based on vendor identity
• Remains constant across all enclaves signed by the same authority
• Enables version-agnostic attestation policies for seamless updates
• Balances security with operational flexibility in deployment pipelines

A cryptographic protocol where an enclave proves its identity and integrity to a remote relying party by presenting its measurement alongside a hardware-signed quote. This establishes a trust anchor before secrets are provisioned.

• The enclave generates a Quote containing MRENCLAVE and other measurements
• The Quote is signed by the platform's hardware root of trust
• A remote verifier checks the signature and compares the measurement against a known-good whitelist
• Only upon successful verification are decryption keys or secrets released

A mechanism that cryptographically binds data to a specific enclave's measurement and security version. This allows an enclave to securely persist secrets to untrusted storage and retrieve them only on the same platform.

• Seal Key is derived from the enclave's measurement and a hardware root key
• Data sealed to MRENCLAVE can only be unsealed by the exact same enclave binary
• Data sealed to MRSIGNER can be unsealed by any enclave from the same vendor
• Protects data at rest while maintaining the chain of trust from the TEE

An Intel-provided attestation infrastructure that allows data center operators to run their own attestation services without relying on Intel's cloud-hosted service. It uses the measurement as the core identity primitive.

• Provides a flexible, self-hosted verification cache for enclave measurements
• Uses the Platform Certificate and Collateral to validate the Quote's hardware signature
• Enables scalable, privacy-preserving verification without external network dependencies
• Essential for air-gapped or sovereign cloud deployments

The process of patching and updating the security-critical components of a platform. Enclave measurement includes the TCB version, allowing verifiers to detect and reject attestations from vulnerable firmware or microcode.

• A TCB Recovery Event increments the platform's security version number
• Enclave measurements are bound to a specific TCB level
• Data sealed to an old TCB level may become inaccessible after an update
• Ensures that attestation reflects the current, patched security posture of the hardware