Patent attributes
Techniques and arrangements for managing risk of fraudulent transactions made by a point-of-sale (POS) device operating in an online and an offline mode. In some instances, a payment service may maintain a merchant profile with a list of merchant specific criteria. The payment service may encrypt and send the merchant specific criteria to the POS device associated with the merchant. The encrypted data may include a list of payment instruments used in previous successful transactions, customer transaction histories, and other customer information. The POS device may determine, upon receiving a payment instrument identifier in a transaction, whether the payment instrument has been used in a previous successful transaction. If the POS device determines the payment instrument has been used, it may process the transaction. If not, the POS device may warn the merchant that the transaction is a high-risk transaction.