Every deal desk has a folder of proof-of-funds documents it cannot verify. FlashRouter's format replaces the folder with a signature.
What is wrong with the old proofs
A screenshot can be edited in a minute. A bank letter describes a balance on a past date and says nothing about liens. A live wallet balance can be borrowed in a flash loan, shown, and returned inside one transaction. None of them travels with a way to check.
What the attestation contains
The address, the asset, the balance observed at two finalized blocks across a window, the block hashes, a timestamp, an expiry (24 hours), and an Ed25519 signature over all of it. The verifier page recomputes and checks the signature; a counterparty does not have to trust the sender or the desk.
What it does not claim
It does not say the funds are unencumbered, lawful, or owned by the person presenting it. It says: this address held this balance at these finalized blocks, signed by this key. Pair it with Know Your Athlete or an organization verification for the who.
Where it is used
Counterparty checks before an engagement, escrow readiness, and the deal-desk step that used to be a phone call to a banker.
Questions people ask
How long is an attestation valid?
24 hours from issue; after that the counterparty asks for a fresh one.
Does it prove ownership?
No. It proves a balance at finalized blocks under a signature. Ownership and authority come from a verification record.