Using the new iMX7D (dual Cortex-A7)
Some additional background information on POS and BLE.
Bodies like the PCI Security Standards Council have moved towards higher security standards as a requirement for BLE in payment applications. The BT 4.2 standards include such improvements, but the necessary profile (LE Secure connections) like many of the 4.2 features is optional, so is implemented on some Bluetooth products and not on others - LE Secure connections requires additional firmware either in the ROM image or it can be patched in.
LE Secure Connections introduces Elliptic curve Diffie–Hellman (ECDH) for key generation via a new software block and a new pairing procedure for the key exchange.
This provides protection from eavesdropping for all pairing methods and protection against man-in-the-middle attacks for Numeric Comparison, Passkey Entry, and Out Of Band pairing methods.
Broadcom have added
- Generation and management of ECDH keys
- LE Secure Connection pairing requests
- Generation of ECDH keys and Long Term Keys (LTK)
- Generation and exchange of cross transport keys
If you want to use BLE for a POS application, you must check that the chip is certified for BT 4.2 plus the specific LE Secure connections block is supported - as it is an optional feature even if the chip is 4.2 capable.