The non-techie stuff:
The encryption of our NFC tags is similar to the secure encryption of a chipped bank card – so they are very secure.
If not encrypted, a bank card could be easily scanned and read (like when in close proximity to other people on the tube for example). However, with the special encryption, this can’t happen so no one could scan your details and access your home, office, restaurant, etc. as a result.
For the techies:
It is a 16 or 32 bit CRC, Common Criteria Certificate EAL4+ (the hardware and software), with random key generation and DES with up to 168bit and AES with 128bit encryption.