Live for CPAs · expanding to banks & advisors

Independent proof of bitcoin holdings.

Cryptographically verified. On letterhead. Court-grade. The third-party attestation that bridges crypto and traditional finance.

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NO CRYPTO BACKGROUND REQUIRED · CANCEL ANY TIME · 20-MINUTE ONBOARDING
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— Verified by
BIP-137 challenge
SHA-256 chained log
TLS 1.3
PKCS#7 signing (soon)
SOC 2 (in flight)
Who is this for?

Built for the professionals who put their name on a number.

FOR ONE-TIME USE

I'm an individual

Need one document — for a loan, a court filing, a mortgage. No firm, no subscription. Pay per attestation.

Get one attestation →
FOR FIRMS

I'm a CPA

Run attestations on behalf of clients. Branded reports. Portfolio workspaces. Audit-binder export on the roadmap.

Start with Pro →
EXPANDING TO — VERTICALS ON THE ROADMAP
AttorneysBanksTitle companiesInsuranceIRA custodiansFamily offices
PILLAR — 01

Independent

1

We are not the customer and not their advisor. We are the third party that reads the chain and signs the document — like a notary, but with math.

PILLAR — 02

Cryptographic

2

The customer signs a challenge with their private key (BIP-137). We verify the signature before we attest. No signature, no document.

PILLAR — 03

Independently verifiable

3

Anyone with the verify code + passphrase can re-check the document against the on-chain record. Trust isn’t in us — it’s in math.

The deliverable

One PDF. Independently verifiable.

A document a banker can email to underwriting. A document a court will accept. A document anyone can re-verify with a code, with no login.

01
Standard
Default Keystodian-branded attestation
02
Branded
Your firm's logo, name and independence affirmation
03
Audit-binder export
Every attestation across a period, bundled · roadmap
Keystodian
BLK 887,234
Independent attestation of bitcoin holdings
CLIENT: ASTOR ADVISORY GROUP · PORTFOLIO 2026-Q1
Confirmed holdings
2.41370 ₿ · $164,832 USD
addresses3 · all signed
block height887,234
price sourceCoinGecko @ block ts
sha-256a3f4…7e91
VERIFY · keystodian.capital/vKYS-7H4M-9PQR
VERIFIED
BIP-137
Keystodian
BLK 887,234
Independent attestation of bitcoin holdings
CLIENT: ASTOR ADVISORY GROUP · PORTFOLIO 2026-Q1
Confirmed holdings
2.41370 ₿ · $164,832 USD
addresses3 · all signed
block height887,234
price sourceCoinGecko @ block ts
sha-256a3f4…7e91
VERIFY · keystodian.capital/vKYS-7H4M-9PQR
VERIFIED
BIP-137
The alternative landscape

Six weeks. Ten thousand dollars. Or a screenshot.

The crypto attestation market has two extremes — and a gap in the middle that costs firms time and credibility.

ApproachCostTimeQuality
Wallet screenshotFreeInstantForgeable · not court-admissible
Big 4 audit$10,000+6 weeksSlow · expensive · overkill
KeystodianYOU ARE HERESubscriptionMinutesCryptographic · third-party · filed-able

Your bitcoin has value.
Make it official.

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