Six steps. No mystery.
From portfolio to independent verification. Every step is logged, signed, and reproducible.
Create a portfolio.
A portfolio groups bitcoin addresses that belong on the same attestation: by entity, by purpose, by storage. Business, personal, trust, hot wallet, cold storage. CPAs run dozens for clients; an individual may have one or two.
Add the addresses.
Pull in every address holding the assets, from any wallet — Coldcard, Trezor, Sparrow, Bitcoin Core, Electrum, Ledger. Mix wallet types as needed. Keystodian doesn't care which wallet, only that the owner can prove control.
The owner signs a challenge.
For every address, the owner signs a unique single-use challenge with the private key (BIP-137). The signature is the proof — it cryptographically demonstrates the owner controls the addresses holding the assets. We never see the key. When every address is signed, the owner clicks Request attestation.
We read the chain.
Keystodian verifies every signature against its address, then reads each address's balance at a specific block height. We snapshot block, timestamp, and the price source we used. Every operation is logged with a SHA-256 chain.
We sign the document.
A PDF is generated — branded if the firm has white-label enabled — containing the verified holdings, the block reference, the price source, and a verify code. The firm reviews and releases it. The document includes our independence affirmation.
BIP-137
Anyone can re-verify.
The recipient — a banker, an underwriter, a court clerk — visits keystodian.capital/verify, enters the verify code and passphrase, and re-runs the check against the chain. The document is independently verifiable. Trust is in the math, not in us.
The recipient doesn’t have to trust us.
Most attestations ask the reader to take someone’s word for it. This one doesn’t. The math behind the document is reproducible — and anyone, with no account and no payment, can re-run the check at any time.