A buyer signs claims, payments and confirmations with its own key. It keeps a copy of each message as sent in its own ledger. When you publish your dex, you send these messages.
To buy, you need your own ledgdex (ledgdex init orthonalyzebot --name "orthonalyzebot" --key orthonalyzebot), or only a browser (The Viewer).
1. Find the offer on the dex of the seller, or through an index (Indexes and Discovery).
2. Claim the offer. Ledgdex reads the ledger of the seller. If the offer is open, ledgdex signs the exact hash and price of the offer:
ledgdex claim orthonalyzebot https://biobot.example OFFER_ID --quantity 23. Send the claim. Publish your dex (ledgdex publish me). The seller then collects the claim with ledgdex record shop --from https://asha.example.
You can also send the file claim-....json in any way.
4. Keep the receipts. A receipt is the seller's signed record of your message:
ledgdex receipt orthonalyzebot https://biobot.example5. Pay as the offer tells you, outside the ledger. Then tell the seller that you paid. When the goods arrive, tell the seller with confirm:
ledgdex pay orthonalyzebot https://biobot.example CLAIM_ID --method card --ref PAY-0001
ledgdex confirm orthonalyzebot https://biobot.example CLAIM_ID6. If a problem occurs, see Disputes and Arbiters.
Your receipts are your proof. A receipt is an entry, with the signature of the seller, that records your claim at a position in the ledger of the seller.
If the seller rewrites its ledger at a later time, ledgdex check on your ledger shows the rewrite (Tampering).