This project implements a secure form of storage for sensitive information such as passwords or identification numbers. It is built based on AVR ATmega1284 and PN532 NFC Shield from Adafruit. The project is modeled after Shamir’s secret sharing algorithm. It allows user to distribute information regarding the secret key among several agents. In this way, you would need a certain minimum threshold number of agents to collaborate to generate the secret key.
The system uses Near-field communication (NFC) as the medium through which to transfer information. NFC builds on top of RFID and was chosen for both its limited range and versatility. Currently, it implementation stores information on NFC cards, but future enhancements can allow communication with other devices such as NFC-enabled phones.
For demonstration purposes, the encoder and decoder are combined into one device. The user can specify the number of agents and the threshold number to encode a certain key. The other option is to use the Advanced Encryption Standard (AES) to encrypt the data and store it on a single card. The user is able to choose either option and interact with the device through a keypad and a television screen.