American Express Company
Sending a cryptogram to a POS while disconnected from a network

Abstract:

A system is configured for detecting a point of sale, receiving a personal identification number (PIN), generating a PIN based key using a message digest of the PIN, decrypting a data encryption key (DEK) using the PIN based key, and generating a DEK based dynamic key using the PIN based key. The system may also decrypt a session key using the DEK based dynamic key, generate a cryptogram from the session key, and send the cryptogram to the point of sale.