US DHS concludes that RFID chips are unsuitable for "human tracking"

You may already be familiar with RFID chips as the tags that are sometimes found in books or attached to CDs and DVDs to prevent theft. Increrasingly, these chips are being added to passports as a way of permitting contactless reading of passport data.

However, in a recent report from the US Department of Homeland Security "disfavoured" the use of RFID tags for person ID purposes:

"RFID can reduce the delay when people pass through chokepoints that require identification. However, transmission of information from cards to verifiers is not a significant cause of the delay in such transactions compared to the authorization and verification steps.

"RFID permits the use of encryption, which can control forgery and tampering with
identification documents. This is not a unique characteristic of RFID, however. It is part of many digital technologies, including contact chips, bar codes, magnetic stripes, and watermarked printing.

Against these small incremental benefits of RFID are arrayed a large number of privacy concerns. RFID deployments’ digitally communicated information is easier to collect, save, store, and process, and is, therefore, more easily converted to surveillance than other methods. The silent, unnoticeable operation of radio waves means that individuals will always have difficulty knowing when they are being identified and what information is being communicated, leaving them vulnerable to increased security risks such as skimming and eavesdropping. "