Attestation Results

Attestation results produced by Remote Attestation Services are in EAT Attestation Result (EAR) format.

There is library support for working with EARs available for Go, Rust, C, and Python languages.

At the core of an EAR is a Trust Vector defined by AR4SI IETF Draft, which breaks down the appraisal of attestation evidence into eight categories (a particular Attestation Scheme may not utilize all of the categories).

EARs maybe serialised as either JWT or COSE messages (Remote Attestation Services produces results as JWT only).

Example attestation result

This is JSON serialization of a sample attestation result as produced by Remote Attestation Services for Arm PSA evidence.

{
    "ear.status": "affirming",
    "ear.trustworthiness-vector": {
      "instance-identity": 2,
      "configuration": 0,
      "executables": 2,
      "file-system": 0,
      "hardware": 2,
      "runtime-opaque": 2,
      "storage-opaque": 2,
      "sourced-data": 0
    },
    "ear.appraisal-policy-id": "policy:PSA_IOT",
    "ear.veraison.annotated-evidence": {
      "eat-profile": "http://arm.com/psa/2.0.0",
      "psa-client-id": 1,
      "psa-security-lifecycle": 12288,
      "psa-implementation-id": "YWNtZS1pbXBsZW1lbnRhdGlvbi1pZC0wMDAwMDAwMDE=",
      "psa-boot-seed": "3q2+796tvu/erb7v3q2+796tvu/erb7v3q2+796tvu8=",
      "psa-software-components": [
        {
          "measurement-type": "BL",
          "measurement-value": "h0KPxSKAPTEGXnvOPPA/5HUJZjHl4Hu9eg/eYMTPJcc=",
          "signer-id": "rLsRx+TaIXIFUjzkzhokWuGiOa48a/2eeHH35di66Gs=",
          "version": "2.1.0"
        },
        {
          "measurement-type": "PRoT",
          "measurement-value": "AmOCmYm2/ZVPcrqvL8ZLwuLwHWktTecphuqAj26ZgT8=",
          "signer-id": "rLsRx+TaIXIFUjzkzhokWuGiOa48a/2eeHH35di66Gs=",
          "version": "1.3.5"
        },
        {
          "measurement-type": "ARoT",
          "measurement-value": "o6XnFfDMV0pzw/m+u2vCTzL/1bZ7OHJEwskJ2neaFHg=",
          "signer-id": "rLsRx+TaIXIFUjzkzhokWuGiOa48a/2eeHH35di66Gs=",
          "version": "0.1.4"
        }
      ],
      "psa-instance-id": "Ac7rrnuJJ6MiflMDz14PH3s0u1Qq1yUKwD+83jbsLxUI",
      "psa-verification-service-indicator": "https://psa-verifier.org",
      "psa-nonce": "QUp8F0FBs9DpodKK8xUg8NQimf6sQAfe2J1ormzZLxk="
    }
}