An improved NFC device authentication protocol.

Aimed at the security authentication problem between Near Field Communication (NFC) devices, this paper uses the technology of asymmetric encryption algorithm, symmetric encryption algorithm, hash function, timestamp and survival period to improve the confidentiality, performance and security of the protocol. The symmetric encryption algorithm encrypts the transmission content, while the asymmetric encryption algorithm encrypts the shared key. The whole authentication process is secure, and the key distribution is secure.

A Comparative Study of Pressureless Sintered Nanostructured Hydroxyapatite/TiO₂ Composites Prepared by Different TiO₂ Addition Methods.

Two methods of TiO₂ addition were applied to prepare hydroxyapatite/TiO₂ (HA/TiO₂) composite, i.e., hydrolysis TiO₂ in HA powders (N-HA/TiO₂) and mixing commercial nano-sized HA and TiO₂ powder (C-HA/TiO₂).