I haven't seen anything in the Whitepaper about "Reputation" or "Trust" of users, but I think they would be required. This may require some form of registration process. Here are a couple of possibilities.
Regarding a peer-to-peer transaction, how do you ensure that both peers add the appropriate transaction fee to ensure it is confirmed by the network allowing both parties to receive their trade?
Example: User A exchanges Bitcoin for Dash with User B. Neither user sets a fee. User A receives Dash right away, User B sees the Bitcoin transaction broadcasts to the network but it never gets confirmed.
Could it be possible for a user to outperform the validator's verification and transaction broadcast process causing a double-spend transaction and resulting in one user ending up with nothing?
Would a "Report User" feature be required if someone gets screwed out of their transaction?
Thanks for the feed back, regarding the verifications, they will be done by the validator, if there is any issue regarding the transactions it would be a fail due to NVO, there will be several verifications done by both sides prior to allow a transaction broadcast, if the user doesn't defines a transaction fee, it will be defined by the wallet when the order is sent. in order to cheat on the validator, one would have to get access to the validator which is secured by safeNet's encryption and protocole.
My second question may not have been clear enough. Since users control their private key, it is possible for them to have a non-NVO wallet that also broadcasts transactions for the same address. If I understand it correctly, there would be a small window of opportunity (fractions of a second) between when the validator verifies funds on the network and when it broadcasts a transaction. A user could broadcast a transaction with their non-NVO wallet after the validator has verified funds but before it broadcasts a transaction. The network will accept the first transaction from the non-NVO wallet broadcast and reject the validators broadcasted transaction as a double-spend. An attacker could quite easily take advantage of this critical loop-hole, hence the need for some measure of "Trust" between users on the exchange when conducting a transaction. If exchange volumes increased to a high level, would it be possible for a trusted user to launch a continuous massive double-spend attack across the market resulting in huge losses to users? DEXs are still a new concept and I don't know if this is a vulnerability or if it has been addressed or exploited yet.