Patent ID: 8515073

Claim:
A method for secure communication between a plurality of electronic devices in a Near Field Communication (NFC) network, the method performed at a first electronic device comprising: sharing, in an NFC environment, a plurality of keys and a key index referencing the keys with a second device among the plurality of electronic devices prior to exchanging data therewith, wherein, in the NFC environment, a different sequence number according to a sequence number count is inserted in each data frame of a current data frame transmitting sequence, and an encryption key change normally occurs at the end of a sequence number count cycle; selecting a first key among the plurality of keys and exchanging data encrypted based on the selected first key with the second device; and replacing the first key with a second key among the plurality of keys, at a time during the current data transmitting sequence prior to the expiration of the sequence number count cycle, after at least one predetermined criterion has been satisfied, and communicating the key replacement between the first and second devices by referencing the second key in the key index, by transmitting a key change request to the second device and receiving a response thereto from the second device, wherein the key replacement associated with the request is made only if the response is an acceptance of the key change, and thereafter exchanging data between the first and second devices encrypted with the second key.