Standard marketplace escrow is convenient but requires trusting the marketplace operator to hold funds honestly during the transaction period. Multi-signature (multi-sig) escrow eliminates this trust requirement by using cryptographic key distribution to ensure that no single party — not the buyer, vendor, or marketplace — can move funds unilaterally.
The most common implementation is a 2-of-3 multi-signature scheme. Three keys are generated: one for the buyer, one for the vendor, and one for the marketplace. Funds can only be moved when any two of the three keys sign the transaction. This means the marketplace cannot steal funds (it needs a buyer or vendor key), and a dishonest vendor cannot collect funds without buyer approval (or marketplace arbitration).
To initiate a multi-sig transaction: navigate to the product listing and select multi-sig checkout, generate your buyer key pair (the platform provides guidance for this in the transaction interface), fund the multi-sig wallet with XMR, and await vendor confirmation. The vendor also generates their key pair and the marketplace generates its key. The three-key structure is established before funds move.
If the order completes successfully: the buyer signs a release transaction with their key, the vendor countersigns with their key, and the funds are released. If there is a dispute: either party opens a dispute, provides evidence, and the marketplace uses its key to co-sign with the party it rules in favor of.
The critical importance of key backup cannot be overstated. If a buyer loses their private key, they cannot participate in releasing funds — requiring marketplace intervention. Store your key backup in an encrypted, offline location before initiating any multi-sig transaction.