Proof of Reserves
AuditKey checks reserves directly on the blockchain, and an independent auditor signs the report. Monthly, quarterly or on demand, public or private, for stablecoin issuers, tokenization platforms, exchanges and privacy protocols.
Before AuditKey, our team ran proof of reserves for Brazilian stablecoins and tokenization platforms under the name Fact Finance. That work, its clients and its method are now part of AuditKey, alongside our KYT.
A reserve report answers "is my token backed?" with data, not promises.
Exchanges, banks and distributors want an independent report before they accept a token.
Brazil's Central Bank already requires proof of reserves from crypto custodians, and the GENIUS Act will require monthly reports from US issuers.
Stablecoins
We read the total number of tokens issued on every network directly from the blockchain, compare it with bank and custodian statements, and show how reserves are split by asset type. Holders get a public page with every report, and the auditor signs each one.
Tokenization platforms
For tokenized receivables, real estate, commodities and other real-world assets, we compare the token records on the blockchain with custody records, registrar data and asset documents. Investors know each token matches an asset that exists.
Exchanges & custodians
Each customer can check that their own balance was included, without seeing anyone else's. We also prove the exchange controls the wallets that hold the reserves. Reports can be public, or shared only with partners and regulators.
Privacy protocols
Early access
In privacy pools, each user's balance is hidden. We compare the total deposited in the pool with its balance on the blockchain and use zero-knowledge proofs to show the pool can pay everyone, without revealing anyone's balance.
Every report is signed by an independent auditor under Brazilian (NBC) and international (ISAE) assurance standards.
| NBC TO 3000 | NBC TSC 4400 | |
|---|---|---|
| Type of engagement | Assurance on a specific subject, other than an audit or review of financial statements | Agreed-upon procedures |
| What the auditor delivers | A conclusion, with reasonable assurance (positive opinion) or limited assurance | A description of what each agreed check found, with no conclusion |
| International equivalent | ISAE 3000 | ISRS 4400 |
| When to use | Public reports for holders, partners and regulators | Monthly checks between reports, or internal and partner checks |
The report is signed by the independent auditor, not by AuditKey. Each report covers its cut-off date. We produce and compare the data; the auditor tests it and concludes.
Signed by Rodrigo Molin, independent auditor registered with CNAI (CFC).
1
AuditKey + client
We agree on the asset, the wallets and the standard the auditor will follow.
2
AuditKey
We pick a cut-off date and gather blockchain balances and statements for that same date.
3
AuditKey
We compare what is owed with the reserves and document every difference.
4
Independent auditor
The independent auditor tests the evidence and signs the report.
5
AuditKey + client
The signed report records the data so it cannot be changed later.
From January 2027, US payment stablecoin issuers must publish a monthly reserve report, certified by their CEO and CFO and examined by a PCAOB-registered accounting firm. AuditKey prepares the data that report is built on: tokens issued on every network, reserve comparison and reserve breakdown, ready for your examiner. Operating in Brazil? Resolution BCB 520 already requires proof of reserves from crypto custodians.
Privacy protocols can prove the pool can pay everyone without exposing a single user. That proof is part of the engagement.
With one provider, prove the reserves exist and that the money used to issue and redeem tokens comes from clean sources.
Brazil's Central Bank (Resolution BCB 520) requires crypto service providers to keep client assets separate from their own. AuditKey compares client wallets with what is owed to each client and documents that separation in the report.
Engagements follow NBC TO 3000 and NBC TSC 4400, delivered in Portuguese, Spanish and English.
How the cryptography and Merkle tree work that let every customer check their own balance. For crypto exchanges and custodians. October 2026 edition.
How AuditKey proof of reserves works.
It is an independent check that the assets backing a token or a platform cover everything it owes to customers. AuditKey compares blockchain data with reserve statements, and an independent auditor tests the result and signs the report.
No. A financial statement audit covers all of a company's accounts. Proof of reserves covers one question: whether reserves cover what is owed, on a cut-off date. That is why AuditKey reports are assurance or agreed-upon procedures engagements, not audits.
Choose NBC TO 3000 when holders, partners or regulators need a conclusion from the auditor. Choose NBC TSC 4400 when a set of agreed checks is enough, like monthly checks between reports. AuditKey prepares the data for both.
Resolution BCB 520 requires proof of reserves and client asset segregation from crypto custodians. AuditKey compares client assets with what is owed to each client, and an independent auditor signs the report. Confirm your obligations with counsel.
The GENIUS Act requires monthly reserve reports examined by a PCAOB-registered accounting firm. AuditKey prepares the data for that examination, but the examination itself must be performed by a PCAOB-registered firm.
Yes. Reports can be published on a public page, shared only with partners and regulators, or both.
Monthly, quarterly or on demand. For issuers that need it, we also track reserves on the blockchain between reports.
AuditKey compares the total deposited in the pool with its balance on the blockchain and uses zero-knowledge proofs. This proves the pool can pay everyone without revealing any user's balance.
AuditKey builds a Merkle tree, a structure that combines every customer's balance. Each customer gets a proof that their balance was included, without seeing anyone else's.
