Proposal Explorer

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Built for an adversarial prover

Side-channel suppression for isolated facilities and Hardware-enabled guarantees (flexHEG) and guarantee processors

No new hardware needed

Safeguard attestation and Chip registries and manufacturing records

Published attempts to break a system, including those that found failures. Testing history does not show that open flaws are resolved.

• Safeguard attestation: Analysis
• Side-channel suppression for isolated facilities: Analysis
• Hardware-enabled guarantees (flexHEG) and guarantee processors: Analysis
• Chip registries and manufacturing records: Analysis

Open significant flaws

17 flaws in 4 mechanisms

• Attestation shows a safeguard ran, not that it is effective in Safeguard attestation

  Proof of guardrail ensures that the guardrail executed, but the guardrail can still err or be jailbroken. Because the guardrail must be open source, a malicious developer can attack it with jailbreaks while still presenting a valid proof. In the authors' evaluation, Llama Guard 3 reached an F1 score of 0.56 on the unsafe class of the ToxicChat dataset. The authors state that proof of guardrail should not be interpreted or advertised as proof of safety. ¹

  Theoretical argument · Significant · Open. On the record

• Selective attestation leaves traffic uncovered in Safeguard attestation

  Attestations are issued per response. In the prototype, the agent offers them when it receives high-stakes questions, so nothing shows that unattested traffic went through the same path. PAL*M's authors note that a prover could cherry-pick favourable executions, and suggest verifier-published nonces or requesting only session-level proofs. A governance analysis notes that auditors also need assurance that all activity is accounted for, since a host could start a second confidential virtual machine that bypasses monitoring. ^{1 4 9}

  Theoretical argument · Significant · Open. On the record

  Related mechanism R2 On-chip telemetry from timing, memory and performance counters: On-chip counters are a proposed route to evidence about everything a chip runs, including a second virtual machine that skips the safeguard. A pointer, not evidence that this flaw is mitigated. Add

• Measurements may omit behaviour-relevant configuration or runtime changes in Safeguard attestation

  Every component that influences inference behaviour must be covered by the launch measurement, including feature flags, environment variables and invocation arguments. A launch measurement also does not show that a program keeps running as measured if the kernel is later compromised. ⁹

  Theoretical argument · Significant · Open. On the record

• Components outside the attested boundary in Safeguard attestation

  In the proof-of-guardrail experiments, the guardrail model and the agent's backend model were both reached through external APIs, and the authors leave the decision to trust those APIs to the verifier. The measured wrapper must also have no vulnerability that lets the unmeasured agent bypass the guardrail, for example by executing arbitrary commands inside the enclave. The code's README states that the enclave does not currently restrict the agent's arbitrary command execution, which could be used to bypass guardrails. ^{1 2}

  Theoretical argument · Significant · Open. On the record

• Memory-bus interposition extracts attestation keys and forges attestations in Safeguard attestation

  Applies to variants using the affected Intel or AMD trust roots. PAL*M excludes physical attacks. A TDX-backed safeguard claim against a physical host attacker would be defeated, but these studies do not demonstrate a break of the AWS Nitro proof-of-guardrail prototype or of verifier-side recomputation.

  The TEE findings cover DDR5 attacks on Intel TDX, the H100 relay demonstration, DDR4 attacks on AMD SEV-SNP, and software-only SEV-SNP forgery before AMD's fixes. These are inherited hardware limits; a governance analysis explains why physical access matters in a treaty setting. ^{1 4 7 8 9 10 11 12 13}

  Response: Intel and AMD place the physical attack class outside their threat models, according to the researchers. AMD reports firmware fixes for RMPocalypse.

  Demonstrated attack · Significant · Open · Inherited finding. On the record · Related finding in TEE remote attestation for AI workloads

  Related mechanism R1 Hardware-enabled guarantees (flexHEG) and guarantee processors: A tamper-protected enclosure around the chip is the proposed answer when the party that holds the hardware may attack it physically. A pointer, not evidence that this flaw is mitigated. In the proposal.

• Supply-chain implants may evade inspection in Side-channel suppression for isolated facilities

  Cankaya identifies malicious hardware embedded deep in purchased components as a residual risk that visual inspection and disassembly may not catch. He notes that radiographic examination under high-security standards could mitigate it. ¹⁴

  Theoretical argument · Significant · Open. On the record

• Openings for airflow, power and optics weaken shielding in Side-channel suppression for isolated facilities

  Cankaya notes that keeping attenuation high while passing high-power airflow, cabling and optical links adds complexity beyond existing shielded-enclosure specifications. ¹⁴

  Theoretical argument · Significant · Open. On the record

• Inspection assumptions may not hold in Side-channel suppression for isolated facilities

  The design's statistical argument assumes that visual or disassembly inspection catches every flaw that is present in a sampled unit. Cankaya is unsure whether destructive teardowns are defence-dominant or offence-dominant. ¹⁴

  Open question · Significant · Open. On the record

• State attackers can likely defeat current secure enclosures in Hardware-enabled guarantees (flexHEG) and guarantee processors

  The flexHEG authors write that "nation-state attackers can likely compromise the best current secure enclosures", and that the marginal cost of circumvention per device is hard to estimate. RAND similarly judges that anti-tamper measures "would not be insurmountable for a determined and well-resourced adversary", although they raise costs and can reveal tampering. ^{16 18}

  Theoretical argument · Significant · Open. On the record

• Firmware-only retrofits rely on Secure Boot, which fault injection can bypass in Hardware-enabled guarantees (flexHEG) and guarantee processors

  Part II notes that the most common attack on Secure Boot replaces the firmware and applies a voltage glitch while the signature is being checked. It also notes that sophisticated actors may use microprobing or laser voltage probing to read key registers. ¹⁶

  Theoretical argument · Significant · Open. On the record

• Many important rules cannot be checked on-chip in Hardware-enabled guarantees (flexHEG) and guarantee processors

  Malicious intent "is not a technical property observable on-chip", and misuse depends on what is done with a computation's results. A guarantee processor cannot easily tell whether a network is the whole system or one expert in a mixture-of-experts system. Part III judges that a fully local ruleset "may not be entirely feasible" for the same reason. ^{15 17}

  Theoretical argument · Significant · Open. On the record

• FLOP accounting can be laundered through external data in Hardware-enabled guarantees (flexHEG) and guarantee processors

  Results of earlier or parallel workloads could be hidden in the "external data" fed to a device, which would falsify the total FLOP count unless the inputs are explained or time delays are imposed. ¹⁶

  Theoretical argument · Significant · Open. On the record

• Supply-chain diversion and hidden backdoors in Hardware-enabled guarantees (flexHEG) and guarantee processors

  Components could be diverted before a guarantee processor is added, and backdoors could be introduced during design or manufacturing. Open-source designs and physical scans of randomly selected chips are proposed as countermeasures. Part III proposes international oversight of production and extensive testing of a random sample of finished devices. ^{16 17}

  Open question · Significant · Open. On the record

  Related mechanism R1 Chip registries and manufacturing records: Records each chip's identity and owner from the fab onwards, which bears on diversion before a guarantee processor is fitted. It does not address hidden backdoors. A pointer, not evidence that this flaw is mitigated. In the proposal.

• Coverage stops at flexHEG-equipped chips in Hardware-enabled guarantees (flexHEG) and guarantee processors

  Motivated actors will always be able to use some compute that is not flexHEG-equipped. Recalling existing consumer GPUs would likely be impractical, and reaching perfect coverage, or conclusively proving that no secret government data centres exist, would be "practically quite difficult". ^{15 17}

  Open question · Significant · Open. On the record

  Related mechanism R1 Chip registries and manufacturing records: Accounts for which chips exist and who holds them. A pointer, not evidence that this flaw is mitigated. In the proposal.

  Related mechanism R1 Remote detection of data centres: Looks for undeclared facilities that hold other chips. A pointer, not evidence that this flaw is mitigated. Add

• Records cover only chips that were recorded in Chip registries and manufacturing records

  A registry or commitment accounts only for chips entered into it. Cankaya asks how a verifier would know it had found all chips, or how much "dark compute" remains, and notes that a fraudulent original record would mean unregistered chips had been made in advance. Halstead and Larsen propose reconstructing earlier production by auditing upstream suppliers. ^{23 25}

  Theoretical argument · Significant · Open. On the record

  Related mechanism R1 Remote detection of data centres: Looks for large data centres that were never declared, which a registry cannot show. A pointer, not evidence that this flaw is mitigated. Add

• Documents and serial numbers can be forged in Chip registries and manufacturing records

  Avellar and Grunewald note that export documents can be forged, that companies can hide information behind obscure corporate structures, and that it may be possible to forge serial numbers on chips and racks. They recommend cryptographic attestation of a powered-on chip as an extra check. ²²

  Theoretical argument · Significant · Open. On the record

• Insiders could alter records before they are fixed in Chip registries and manufacturing records

  Cankaya argues that insiders who can photograph process secrets could also tamper with production records. A commitment makes changes after publication detectable, but it cannot show that the records were accurate when committed. ²³

  Theoretical argument · Significant · Open. On the record

Not yet demonstrated

R1 Side-channel suppression for isolated facilities, R1 Hardware-enabled guarantees (flexHEG) and guarantee processors and R1 Chip registries and manufacturing records

Need new chip designs

Hardware-enabled guarantees (flexHEG) and guarantee processors

Mechanisms on the map that are not in the proposal. Pointers, not recommendations. ?

• R2 On-chip telemetry from timing, memory and performance counters Add
  • Bears on the open significant flaw “Selective attestation leaves traffic uncovered” in Safeguard attestation. On-chip counters are a proposed route to evidence about everything a chip runs, including a second virtual machine that skips the safeguard.
• R1 Remote detection of data centres Add
  • Bears on the open significant flaw “Coverage stops at flexHEG-equipped chips” in Hardware-enabled guarantees (flexHEG) and guarantee processors. Looks for undeclared facilities that hold other chips.
  • Bears on the open significant flaw “Records cover only chips that were recorded” in Chip registries and manufacturing records. Looks for large data centres that were never declared, which a registry cannot show.
• R3 Model identity attestation Add
  • Safeguard attestation waits on it. Safeguard evidence must be bound to the model actually served, which depends on model-identity attestation.
• R3 TEE remote attestation for AI workloads Add
  • Safeguard attestation waits on it. Frontier model inference typically needs several GPUs, GPU confidential computing is less mature than CPU support, and CPU inference, which an enclave prototype had to use, ran about 100 times slower than GPU inference.
  • Safeguard attestation waits on it. Trust rests on a small number of hardware vendors, and a per-CPU Intel attestation key has been extracted by physical attack.
  • Hardware-enabled guarantees (flexHEG) and guarantee processors depends on it.
• R2 Tamper evidence for verifier devices Add
  • Hardware-enabled guarantees (flexHEG) and guarantee processors waits on it. State-level attackers who hold the hardware can likely compromise the best current secure enclosures.

Missing prerequisites

• R3 TEE remote attestation for AI workloads needed by Safeguard attestation and Hardware-enabled guarantees (flexHEG) and guarantee processors Add
• R3 Model identity attestation needed by Safeguard attestation Add

Shared foundations

• TEE remote attestation for AI workloads relied on by Safeguard attestation and Hardware-enabled guarantees (flexHEG) and guarantee processors

Blockers

15 blockers recorded

• Safeguard attestation
  • No published design shows that all of a provider's traffic passes through the attested safeguard path; current evidence covers individual attested responses. Coverage & hidden compute ^{1 9}
  • Frontier model inference typically needs several GPUs, GPU confidential computing is less mature than CPU support, and CPU inference, which an enclave prototype had to use, ran about 100 times slower than GPU inference. Performance & compatibility. Waits on TEE remote attestation for AI workloads ^{9 26}
  • Trust rests on a small number of hardware vendors, and a per-CPU Intel attestation key has been extracted by physical attack. Hardware trust. Waits on TEE remote attestation for AI workloads ^{7 9}
  • Safeguard evidence must be bound to the model actually served, which depends on model-identity attestation. Evidence binding. Waits on Model identity attestation ^{26 27}
  • No independent red-team or audit of a safeguard-attestation system has been published, and the available prototypes are described by their authors as proofs of concept that have not been stress-tested by a counterparty. Adversarial validation ^{2 6}
• Side-channel suppression for isolated facilities
  • No prototype or red-team exists; the design is a first-pass viability study. Adversarial validation ¹⁴
  • Volume costs of TEMPEST-grade power-line filters are uncertain, because existing products are mostly made to order. Performance & compatibility ¹⁴
• Hardware-enabled guarantees (flexHEG) and guarantee processors
  • Integrated flexHEG needs substantial help from the accelerator manufacturer, and the authors estimate 3.7–7.9 years, from when the manufacturer starts work, for such hardware to displace other accelerators in frontier development. Access & governance ¹⁶
  • State-level attackers who hold the hardware can likely compromise the best current secure enclosures. Hardware trust. Waits on Tamper evidence for verifier devices ^{16 18}
  • Rival states would need to trust the design and manufacture of guarantee processors and enclosures, for example through open design, redundant processors from each side or oversight of production. Hardware trust ^{15 17}
  • Restricting future rule updates would need a formal language for rules, which the authors judge most likely infeasible for early flexHEG versions. Protocol soundness ¹⁵
  • Governing all relevant chips depends on knowing where they are, through chip registries and detection of undeclared facilities. Coverage & hidden compute. Waits on Chip registries and manufacturing records ¹⁷
• Chip registries and manufacturing records
  • No AI chip registry operates, and covering re-exports would need cooperation from re-exporters and foreign governments that may not be feasible everywhere. Access & governance ^{21 22}
  • Linking records to physical chips needs hard-to-spoof unique IDs and inspections. Hardware trust ^{21 22 23}
  • Chips produced before a registry starts must be reconstructed from supplier records. Coverage & hidden compute ^{23 25}

From the family or selected implementation's record. ?

Model weights

Depends on the design for Safeguard attestation.

Hidden by Hardware-enabled guarantees (flexHEG) and guarantee processors.

Not involved: Side-channel suppression for isolated facilities and Chip registries and manufacturing records.

Inputs and outputs

Depends on the design for Safeguard attestation.

Hidden by Hardware-enabled guarantees (flexHEG) and guarantee processors.

Not involved: Side-channel suppression for isolated facilities and Chip registries and manufacturing records.

Training data

Hidden by Hardware-enabled guarantees (flexHEG) and guarantee processors.

Not involved: Safeguard attestation, Side-channel suppression for isolated facilities and Chip registries and manufacturing records.

Safeguard attestation

None on the map

Side-channel suppression for isolated facilities

• R1 AI 2040 inference-only verification stack Proposed architecture, AI Futures Project
• R1 Low-trust AI compute verification system overview Proposed architecture, Machine Intelligence Research Institute
• R1 RAND secure inference data center (SIDC) design Proposed architecture, RAND

Hardware-enabled guarantees (flexHEG) and guarantee processors

None on the map

Chip registries and manufacturing records

None on the map

1. Proof-of-Guardrail in AI Agents and What (Not) to Trust from It, X. Jin et al. (2026). Original
2. Verifiable-ClawGuard: proof-of-guardrail reference code, SaharaLabsAI (2026). Original
3. Safety Without Compromising on Privacy, D. McCann-Sayles et al. (2026). Original
4. PAL*M: Property Attestation for Large Generative Models, P. Chantasantitam et al. (2026). Original
5. Enabling Verifiably-Scoped Monitoring through Large Language Models and Trusted Compute, B. Penchas et al. (2026). Original
6. Auditor-in-a-Box: Tools for Third-Party Auditing, R. Rinberg & B. Penchas (2026). Original
7. TEE.fail: Breaking Trusted Execution Environments via DDR5 Memory Bus Interposition, J. Chuang et al. (2026). Original
8. DDRop: Active Memory Interposer Attacks on Confidential VMs by Dropping DDR5 Writes, J. De Meulemeester et al. (2026). Original
9. On TEEs for Privacy-Preserving Monitoring in AI Governance, Gloria Z (2026). Original
10. Battering RAM: Low-Cost Interposer Attacks on Confidential Computing via Dynamic Memory Aliasing, J. De Meulemeester et al. (2026). Original
11. RMPocalypse: How a Catch-22 Breaks AMD SEV-SNP, B. Schlüter & S. Shinde (2025). Original
12. SEV-SNP RMP Initialization Vulnerability (AMD-SB-3020), AMD (2025). Original
13. A System Overview for Near-Term, Low-Trust AI Compute Verification, N. Cankaya (2026). Original
14. Suppressing Side Channels in an Untrusted Data Center via Retrofitted Defenses, N. Cankaya (2026). Original
15. Flexible Hardware-Enabled Guarantees for AI Compute, J. Petrie et al. (2025). Original
16. Technical Options for Flexible Hardware-Enabled Guarantees, J. Petrie & O. Aarne (2025). Original
17. International Security Applications of Flexible Hardware-Enabled Guarantees, O. Aarne & J. Petrie (2025). Original
18. Hardware-Enabled Governance Mechanisms: Developing Technical Solutions to Exempt Items Otherwise Classified Under Export Control Classification Numbers 3A090 and 4A090, G. Kulp et al. (2024). Original
19. Secure, Governable Chips: Using On-Chip Mechanisms to Manage National Security Risks from AI & Advanced Computing, O. Aarne et al. (2024). Original
20. Hardware-Enabled Mechanisms for Verifying Responsible AI Development, A. O'Gara et al. (2025). Original
21. Verifying International Agreements on AI: Six Layers of Verification for Rules on Large-Scale AI Development and Deployment, M. Baker et al. (2025). Original
22. Near-Term Verification Methods for AI Chip Exports, B. Avellar & E. Grunewald (2026). Original
23. TSMC most definitely has a golden record of all AI chips it made, N. Cankaya (2025). Original
24. Hardware-Level Governance of AI Compute: A Feasibility Taxonomy for Regulatory Compliance and Treaty Verification, S. Ansari (2026). Original
25. Covert AI Projects, B. Halstead & T. Larsen (2026). Original
26. Attestable Audits: Verifiable AI Safety Benchmarks Using Trusted Execution Environments, C. Schnabl et al. (2025). Original
27. How Tinfoil Proves Exactly What Model Is Running, Tinfoil Team (2026). Original