What to check, and in what order
- Control of the wallet. Ask the counterparty to sign a message you write: their name, yours, the date and the deal reference. A valid signature from the address proves they hold its key. Don't accept a signature on a message they chose: it could be old or someone else's.
- Who they are. A signature proves control, not identity. For anything sizeable, the person (or company) should be identity-verified, and the wallet linked to that verification.
- Where the funds have been. AML screening shows whether the wallet has exposure to sanctioned addresses, mixers, darknet markets or stolen funds. Receiving tainted funds can get your own accounts frozen.
- The exact address again, at payment time. Check it hasn't changed, and beware lookalikes.
The easy way: ask for a certificate
A VerifiedWallet certificate covers these in one link. The counterparty signs with their wallet; at Tier 2 they also verify their identity, at Tier 3 the wallet is AML-screened too, and a Business certificate checks the company against the official register and verifies its directors. You open the certificate and see the checks, and you can check the signatures yourself.
Desks that do this every day can automate it: send a Verification Link or use the API, and get the result (with optional proof of funds) back by webhook.
Signing doesn't put either side at risk
Signing a plain-text message moves nothing and gives no one access to the wallet, as long as it's a message and not a transaction or an approval. See is signing a message safe?
Sign once with your wallet: free, no transaction. We counter-sign it and give you a link anyone can verify. From $1.
More guides
How to check who owns a crypto wallet
Addresses don't carry names. Here's what does tell you who's behind one.
What is address poisoning, and how do you avoid it?
A lookalike address in your history, waiting for you to copy it. How to spot it.
Is this crypto address a scam? Check before you send
A one-minute checklist before any crypto payment you can't undo.
Crypto proof of funds: how to prove you hold it
A balance anyone can see, plus a signature only you can make.
Questions
Is a screenshot of the counterparty's wallet good enough?
No. Screenshots are easy to fake and don't prove the wallet is theirs. Ask for a signature on a message you chose, or a certificate.
What should the message they sign say?
Something only valid for this deal: both names, today's date and the deal reference. That stops an old or borrowed signature being reused.
Can a company verify its wallet, not just a person?
Yes. A VerifiedWallet Business certificate checks the company against the official register, verifies its directors and signatories, and links the company to the wallet. Multisig wallets are supported.