This supplemental comment addresses the technical standards needed for NCUA examiners and CPA firms to verify PPSI compliance with GENIUS Act reserve attestation and AML requirements. It recommends role-based access control, cryptographic proof verification standards, W3C Verifiable Credential signing for examination findings, standardized submission packages, tiered examination frequency, and BSA record retention for examination artifacts.
ZKProva Inc.
Compliance Technology & Infrastructure
April 6, 2026
National Credit Union Administration
1775 Duke Street
Alexandria, VA 22314
Re: Docket No. NCUA-2026-0265; RIN 3133-AF69 — Notice of Proposed Rulemaking: Investments in and Licensing of Permitted Payment Stablecoins Issuers (GENIUS Act PPSI Licensing Framework for Federally Insured Credit Unions), 91 FR 6531 — Supplemental Comment on Examination Standards and Auditor Tooling
Dear Members of the NCUA Board:
ZKProva Inc. previously submitted comments on this proposed rulemaking on April 4, 2026 (Tracking ID: mnk-icx3-0rd5), and submits this supplemental comment to address a critical gap in the proposed rule: the absence of technical standards for how NCUA examiners and registered public accounting firms will verify PPSI compliance with GENIUS Act reserve attestation, proof-of-reserves, and anti-money laundering requirements.
ZKProva has built and deployed a production examiner verification portal that enables both NCUA examiners and CPA firms to cryptographically verify PPSI reserve proofs, validate temporal accumulator chains, sign examination findings as W3C Verifiable Credentials, and generate standardized submission packages. Our comments are informed by direct experience building the tooling that examiners will need.
The GENIUS Act requires monthly reserve attestation by a registered public accounting firm (Section 3) and ongoing compliance across CIP, OFAC, AML, wallet management, and federation domains. For the first time in NCUA history, examiners will need to verify compliance that is partially or fully expressed through cryptographic proofs — specifically, zero-knowledge proofs (Groth16 zk-SNARKs) that attest to reserve sufficiency, OFAC non-membership, AML threshold compliance, and wallet credential validity.
The proposed rule establishes that PPSIs must maintain compliance programs and submit to examination, but does not address: (a) how examiners will technically verify cryptographic reserve proofs; (b) what constitutes acceptable evidence that a PPSI's proof-of-reserves chain is intact and unbroken; (c) the roles and access controls for different examiner types (NCUA staff versus CPA firms); (d) standardized formats for examination findings and submission packages; or (e) how examination findings should be signed and transmitted to the NCUA.
Without these standards, each CPA firm and each NCUA examiner will approach PPSI examination differently, leading to inconsistent examination quality, potential gaps in verification, and difficulty comparing examination results across institutions.
The final rule should establish two distinct examiner roles with different access scopes:
1. NCUA Examiner
NCUA examination staff should have unrestricted access to all PPSI issuers under NCUA jurisdiction. When an NCUA examiner authenticates to a PPSI's examination portal, the PPSI should not restrict which issuers or which examination periods the examiner can access. This unrestricted access is consistent with the NCUA's supervisory authority under 12 U.S.C. § 1756 and the examination powers established in NCUA Regulation 741.
2. Registered Public Accounting Firm (CPA Firm)
CPA firms engaged to perform monthly reserve attestation under GENIUS Act Section 3 should have access scoped to the specific PPSI issuer(s) they are engaged to audit. A CPA firm's access should be limited to an explicit list of authorized issuers, and attempts to access data for unauthorized issuers should be denied. This scoping is consistent with the independence requirements of PCAOB standards and prevents scope creep in third-party examinations.
Both roles should authenticate via API key with strong security properties. We recommend a scheme in which a short prefix of the API key (e.g., the first 12 characters) is stored in cleartext for efficient lookup, while the full key is stored as a bcrypt hash for verification. This provides O(1) lookup performance without exposing the full key in database queries.
The core examination task for PPSI reserve compliance is verifying Groth16 zero-knowledge proofs. The final rule should require that PPSI examination portals support at minimum the following verification operations:
1. Single Proof Verification
An examiner should be able to submit a proof artifact — consisting of the Groth16 proof (pi_a, pi_b, pi_c curve points), the public signals (field elements that encode the proven statement), and the circuit identifier — and receive a verification result indicating whether the proof is cryptographically valid for the specified circuit's verification key.
The verification result should include: the circuit name (e.g., "ReserveSufficiency"), the reporting period, the verification timestamp, and a pass/fail determination. If verification fails, the result should include an error description sufficient for the examiner to understand the nature of the failure.
2. Temporal Accumulator Chain Verification
PPSI reserve proofs are not isolated monthly snapshots; they form a temporal chain in which each month's accumulator root is cryptographically linked to the previous month's root. This chain provides tamper-evidence: altering any historical attestation would break the chain at that point and all subsequent links.
The final rule should require that examination portals support chain integrity verification across an arbitrary date range. For a given issuer and examination period (e.g., January 2026 through December 2026), the verification should:
This chain verification is analogous to verifying the integrity of a blockchain's block headers, but applied to monthly reserve attestations rather than transaction blocks. It provides examiners with assurance that the PPSI's reserve history has not been retroactively altered.
3. Batch Verification with Examination Session Recording
For examination efficiency, the portal should support batch verification of all monthly proofs within an examination window. A batch verification operation should:
The examination session record serves as the audit trail for the examination itself — evidence that the examination was conducted, what was examined, and what the results were.
After completing proof verification and chain validation, examiners need a standardized mechanism for recording and signing their findings. We recommend that the final rule require examination findings to be expressed as W3C Verifiable Credentials (Version 2.0) signed with Ed25519Signature2020.
The W3C Verifiable Credential format offers several advantages for PPSI examination:
An examination credential should include: the examiner's identifier (DID), the issuer identifier (DID), the examination period, the number of proofs verified, the chain integrity determination, and any structured findings or observations. The signature should cover the canonical JSON serialization of the credential, ensuring that any modification to the findings invalidates the signature.
The final rule should establish a standardized format for PPSI examination submission packages transmitted to the NCUA. We recommend a ZIP archive format with the following structure:
ncua-ppsi-exam-{issuer-charter}-{period}.zip
+-- manifest.json -- Package metadata, charter number,
| examination period, chain validity
+-- auditor_attestation.jsonld -- W3C VC with Ed25519Signature2020
+-- findings.json -- Structured examination findings
+-- proofs/
+-- 2026-01.json -- Monthly proof + public signals
+-- 2026-02.json -- Monthly proof + public signals
+-- ...
+-- 2026-12.json -- Monthly proof + public signalsThe manifest should include: a format version identifier (e.g., "NCUA-PPSI-EXAM-v1"), the issuer's NCUA charter number, the examination period, the count of monthly attestations verified, the chain integrity determination, the generation timestamp, and the generating examiner's identifier.
Each monthly proof file should contain: the Groth16 proof (pi_a, pi_b, pi_c), the public signals (including the accumulator root, supply commitment, and eligibility root), and the accumulator root for chain verification.
The package should include a SHA-256 hash of the ZIP contents for integrity verification. Upon submission, the NCUA should issue a receipt identifier that the PPSI and the CPA firm can use to confirm successful delivery.
The proposed rule requires annual AML/sanctions compliance certification within 180 days of approval. We recommend that the final rule additionally require:
This tiered approach distributes verification burden across the year, ensures early detection of compliance failures, and aligns the monthly CPA verification cadence with the GENIUS Act's monthly attestation requirement.
Examination session records, signed Verifiable Credentials, and submission packages should be subject to the Bank Secrecy Act's five-year record retention requirement (31 U.S.C. § 5313; 31 CFR 1010.430). The PPSI should maintain these records for a minimum of five years from the date of creation, and longer if subject to an active legal hold. The final rule should clarify that examination artifacts — including the Groth16 proofs themselves, the public signals, and the accumulator chain — are "records" within the meaning of the BSA retention requirements, given that they constitute evidence of compliance with the GENIUS Act's reserve adequacy and anti-money laundering requirements.
ZKProva has implemented the examination framework described above in production. Our implementation includes:
This implementation demonstrates that the standards recommended in this comment are technically achievable and can be deployed by credit union technology vendors without exotic infrastructure requirements.
We respectfully request that the NCUA include the following examination standards in the final rule:
The GENIUS Act introduces cryptographic compliance to credit union regulation for the first time. Examiners need standardized tools, formats, and procedures to verify that PPSIs are meeting their reserve attestation and compliance obligations. The proposed rule establishes the examination obligation; the final rule should establish how examination is conducted in a cryptographic compliance environment. The standards recommended in this comment are technically proven, operationally deployed, and designed to give NCUA examiners the tools they need to protect the credit union system.
ZKProva Inc. welcomes the opportunity to provide technical demonstrations, implementation specifications, or testimony in support of these comments.
Respectfully submitted,
Viswanadha Pratap Kondoju
Founder & CEO
ZKProva Inc. (incorporation pending)
Disclaimer: This page is an informational archive of a public regulatory comment. It does not constitute legal advice. ZKProva Inc. is not a law firm and no attorney-client relationship is created. Not affiliated with, endorsed by, or sponsored by the NCUA, OCC, or U.S. Department of the Treasury.