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Debugging, Recording,
and Replaying Attestation Checks

Attestation errors can be challenging to debug, which is why Warden Supreme comes with the ability to snapshot inputs, configuration, and revocation information of an attestation attempt to later replay and analyse failed attestation checks offline.

The general approach to debugging is the same, regardless of whether Warden Supreme's integrated attestation flow is used or whether raw makoto or roboto attestation checkers are used (see Usage without Integrated Clients)): - Use Warden Supreme’s collectDebugInfo(...) on attestation errors to capture inputs, parsed fields, decisions, and failure reasons. - Persist the debug info object via serialize() / serializeCompact() to logs. - Enrich logs with device make/model, OS and patch levels, so OEM‑specific quirks can be correlated over time. - Replay collected debug statements offline to analyse attestation failures by invoking replay() on a collected debug statement (see Debugging Integrated Attestation).

Privacy Risks and Risk of Chasing Phantoms

We are happy to help you with debugging, but there are three things to keep in mind.

  • Attestation information is personally identifying data if the contained public key is associated with a person.
  • If you publicly paste a debug statement, it will contain your whole configuration, and it will leak information about your service, apps, and the environment of your backend that performs the attestation checks.
  • Only ever share debug statements in its serializeCompact() format for actual debugging, rather than the huma-readable serialize() output.
    • The serializeConpact() format uses a self-describing, forward-compatible multibase encoding.
    • This encoding is transport-safe and survives even Microsoft Outlook's sometimes creative way of "improving" message formatting, as well as "helpful" IDEs and editors being extra-smart when pasting, etc.
    • There were instances in the past where encoding errors in transit caused a full day of debugging effort for nought. Cases like these are precisely the reason why serializeCompact() is the way to record and share debug statements for analysis, while serialize() is the way human-readable representation.

Collecting Debug Info

Warden Supreme's integrated flow already offers a hook to collect debug statements: Whenever the actual attestation check fails (i.e., whenever onAttestationError() is called), a ready-made WardenDebugAttestationStatement is created and passed to this function. Hence, two pieces of information are available to aid debugging:

  1. The attestation error (as the receiver of this lambda)
  2. The debug statement, which can be exported for offline analysis

Warden roboto and makoto attestation offer a collectDebugInfo() function to the same effect, creating a serializable debug statement. The main difference is that it has to be called manually, and the right place ant time to call it depends on how roboto or makoto are integrated. makoto directly produces a WardenDebugAttestationStatement, while roboto's collectDebugInfo() function returns an AndroidDebugAttestationStatement. Both feature the same replay function and contain all information needed to replay the attestation check offline.

Debugging Integrated Attestation

Warden Supreme alreade contains code to load and analyse WardenDebugAttestationStatements that will load and replay() them. The idea is to use an IDE for debugging, by stepping through the attestation workflow and/or exploring stack traces containing detailed information about why an attestation check failed.
For the most straightforward debugging experience:

  • Import this project into IntelliJ IDEA
  • Add a breakpoint here (line 19)
  • Run it in debug mode

Just be sure to add a single argument pointing to a file as described in Diag.kt!

Debugging Raw Android Attestations

Stand-Alone Attestation Parser

To use androidAttestation­Extension on all platforms (e.g., to implement client-side checks on Android), include :supreme-common in your project, and you are ready to go!

A similar utility exists for printing the contents of an Android attestation statement, located in /utils/roboto-diag. More specifically, it pretty-prints the contents of the leaf certificate's Android attestation extension and expects either:

  • -f path/to/leaf/certificate.pem
  • a base64-encoded certificate as the sole argument

It will then pretty-print the attestation extension's contents.

As an added bonus, there is a nullable androidAttestationExtension extension property on the Java X509Certificate and on Signum's X509Certificate class (and certificate chains), which exposes the prettyPrint() function so you can peek into Android attestation extensions at any time. It will even parse malformed values and print those malformed values' DER-encoded hex representation. The underlying parser and the renderer are still experimental, so your mileage may vary. However, it has been tested against literally thousands of attestation proofs captured from real devices and seems to be more robust than Google's parsers, old and new. Plus, its prettyPrint is a huge improvement over relying solely on ParsedAttestationRecord for debugging.

Example of a Pretty-Printed Attestation Record from an Emulator

AttestationKeyDescription(
  attestationVersion = 3
  attestationSecurityLevel = TRUSTED_ENVIRONMENT
  keyMintVersion = 41
  keyMintSecurityLevel = TRUSTED_ENVIRONMENT
  attestationChallenge = b5a4a68423c5d2f610328b3dcc8b408d352afc78fb7eb0d4803bd9ef581654eb
  uniqueId = 
  softwareEnforced =
    AuthorizationList(
      purpose = null
      algorithm = null
      keySize = null
      blockMode = null
      digest = null
      padding = null
      callerNonce = false
      minMacLength = null
      ecCurve = null
      rsaPublicExponent = null
      mgfDigest = null
      rollbackResistance = false
      earlyBootOnly = false
      activeDateTime = null
      originationExpireDateTime = null
      usageExpireDateTime = null
      usageCountLimit = null
      userSecureId = null
      noAuthRequired = false
      userAuthType = null
      authTimeout = null
      allowWhileOnBody = false
      trustedUserPresenceRequired = false
      trustedConfirmationRequired = false
      unlockedDeviceRequired = false
      allApplications = false
      creationDateTime = CreationDateTime(intValue=1752703332000, timestamp=2025-07-16T22:02:12Z)
      origin = null
      rollbackResistant = null
      rootOfTrust = null
      osVersion = null
      osPatchLevel = null
      attestationApplicationId = 
        AttestationApplicationId(
          packageInfos = [
            AttestationPackageInfo(packageName='at.asitplus.atttest', version=1)
          ]
          signatureDigests = [
            34b9762c4d6c90d48431940c57bde7314258b26420efe16ac7f7274f0d330ad5
          ]
        )
      attestationIdBrand = null
      attestationIdDevice = null
      attestationIdProduct = null
      attestationIdSerial = null
      attestationIdImei = null
      attestationIdMeid = null
      attestationIdManufacturer = null
      attestationIdModel = null
      vendorPatchLevel = null
      bootPatchLevel = null
      deviceUniqueAttestation = false
      attestationIdSecondImei = null
      moduleHash = null
    )
  hardwareEnforced =
    AuthorizationList(
      purpose = [
        - SIGN
        - VERIFY
      ]
      algorithm = EC
      keySize = KeySize(intValue=256)
      blockMode = null
      digest = [
        - SHA_2_256
      ]
      padding = null
      callerNonce = false
      minMacLength = null
      ecCurve = P_256
      rsaPublicExponent = null
      mgfDigest = null
      rollbackResistance = false
      earlyBootOnly = false
      activeDateTime = null
      originationExpireDateTime = null
      usageExpireDateTime = null
      usageCountLimit = null
      userSecureId = null
      noAuthRequired = false
      userAuthType = UserAuth(authTypes=[FINGERPRINT], intValue=2)
      authTimeout = null
      allowWhileOnBody = false
      trustedUserPresenceRequired = false
      trustedConfirmationRequired = false
      unlockedDeviceRequired = false
      allApplications = false
      creationDateTime = null
      origin = GENERATED
      rollbackResistant = null
      rootOfTrust = 
        RootOfTrust(
          verifiedBootKeyDigest=c2224571c9cd5c89200a7311b1e37aa9cf751e2e19753e8d3702bca00be1d42c
          deviceLocked=true
          verifiedBootState=Verified
          verifiedBootHash=d415abd0e620d3e8a942a62920195ad893ff0515ab8236931a156bc1f49de444
        )
      osVersion = OsVersion(major=13, minor=0, sub=0, intValue=130000)
      osPatchLevel = OsPatchLevel(year=2025, month=MAY, intValue=202505)
      attestationApplicationId = null
      attestationIdBrand = null
      attestationIdDevice = null
      attestationIdProduct = null
      attestationIdSerial = null
      attestationIdImei = null
      attestationIdMeid = null
      attestationIdManufacturer = null
      attestationIdModel = null
      vendorPatchLevel = PatchLevel(year=2025, month=MAY, day=1, intValue=20250501)
      bootPatchLevel = PatchLevel(year=2025, month=MAY, day=1, intValue=20250501)
      deviceUniqueAttestation = false
      attestationIdSecondImei = null
      moduleHash = null
    )
)