Patent ID: 7474217

Claim:
A system for tracking inventory, said system comprising: a first plurality of RFID tags attached to a first, respective plurality of products within a first container, each of said first plurality of RFID tags including means for broadcasting its respective identity; a second plurality of RFID tags attached to a second, respective plurality of products within a second container, each of said second plurality of RFID tags including means for broadcasting its respective identity; a third, Active RFID tag attached to said first container and including means for hashing the identities broadcast by said first plurality of RFID tags, and broadcasting a result of said hashing of the identities broadcast by said first plurality of RFID tags; a fourth, Active RFID tag attached to said second container and including means for hashing the identities broadcast by said second plurality of RFID tags, and broadcasting a result of said hashing of the identities broadcast by said second plurality of RFID tags; and a fifth, Active RFID tag attached to a third container containing all of said first containers with said first plurality of RFID tags and containing all of said second containers with said second plurality of RFID tags, said fifth Active RFID tag including means for generating a hash value based in part on the results broadcast by said third and fourth Active RFID tags.