What is Proof of Reserves?

If an exchange says you have one bitcoin, how do you know it actually holds it? Think of a coat check that has handed out claim tickets: the tickets aren’t enough, the matching coats have to be there too. Proof of Reserves tries to provide verifiable evidence of reserves instead of a mere assurance from the company.

Usually, the provider proves that it controls specific addresses on the blockchain, for example by digitally signing a message. Their balances can be checked publicly. But to see whether they cover what it owes customers, you also need a reliable record of those liabilities.

Some implementations use a Merkle tree, a cryptographic structure that rolls users’ balances up into a verifiable fingerprint. That way, you can check that your own balance was included without all other customers’ data being made public. This alone doesn’t prove that everyone was included or that the record is complete.

Why it matters

When you leave crypto with a custodian, you depend on its ability to give it back. A meaningful proof of reserves adds transparency: it makes it possible to examine whether the declared assets cover the corresponding liabilities, within the scope that was checked.

We find this ability to verify useful, as long as we know exactly what it proves. Publishing a list of wallets is one thing; checking reserves together with customer balances and a clear description of the method is another.

What to watch out for

Proof of Reserves is usually a snapshot of a specific moment in time, not a guarantee that the same reserves exist at all times. It may also not show loans, encumbrances on the assets or other corporate debts. Even proof of control over a wallet doesn’t prove that its funds are free of third-party claims.

That is why we look at the date, who carried out the verification, which coins are covered and which liabilities were examined. We don’t equate it with a full audit of financial statements or with a guarantee of solvency. To confirm that your balance is included, you never need to give away your private key or your seed phrase.