Design Of Security Bluetooth Host Based On NiosⅡ And Research On Key Agreement

With the development of information technology bluetooth has been widely used. At the same time its security problems are revealed day by day. It is the critical issue how to keep sensitive data transmitted by bluetooth secure. In this paper, security mechanism of bluetooth and threats to it are researched and investigation actualities are analyzed. One scheme for bluetooth security transmission that is based on NiosII and includes both security bluetooth host and key agreement is designed and implemented.Since its own security mechanism of bluetooth can't meet security transmission demand in sensitive environment, security bluetooth host is designed with SOPC in this paper. Customizability of NiosII soft-core processor is taken advantage of to carry out cipher processing and key agreement which enhance the host's security. According to the guidance of balance between resource and speed and the design specification of NiosII, IP core for communication between NiosII and bluetooth module is designed. DMA controller is introduced, which makes two master devices NiosII and DMA can work concurrently. Data transmitting and processing cost in bluetooth host is reduced because of these measures. Furthermore, according to the working process of security bluetooth host switch model between states of NiosII is built and the data packet which not only conforms to HCI transmission specification but also consists of data type, encryption mark, CRC code and key ciphertext is designed. Packets processing procedures are designed in terms of flow direction of different packets. As a result security transmission between bluetooth host and bluetooth module is achieved.As it's liable to eavesdropping and man-in-the-middle attack for the procedure of key generation, considering storage facilities of bluetooth devices and bluetooth communication characteristics, one key agreement protocol which adopts interlock mechanism and encrypts transmitted data by elliptic curve cryptography is proposed in this paper. Analysis shows that this protocol can resist the above attacks effectively and establish session keys safely.Finally, the scheme for bluetooth security transmission raised in this paper is implemented and tested on the home-made platform for bluetooth security research. The results suggest that this scheme should ensure data transmitted by bluetooth against attacks and it be a practicable and efficient way of bluetooth security application. Moreover, the security bluetooth host can not only provide confidentiality protection and error detection but also support reconfiguration mode for function expansion and modification. It settles foundation for further research on the security of other bluetooth services.