And just like The C's said, it will be a stamp, not a chip. 7 billion chips, I don't think so. Here's a few reasons I don't believe it will be a chip. (1) A chip would be able to interface with the system, the possibility of uploading a virus it too much of a temptation. (2) A chip can be broken or removed. (3) The infrastructure for the use of a barcode stamp is already in place.