| In this thesis, we present a secure data communication solution to resolve the problem of receiving information from a remote site. In the proposed system, a server is placed in the control center to handle the data transmission requests and store the data received from remote sites. In addition, a programmed DSP (Digital Signal Processor)-based compact device is placed in each remote site to acquire and forward the information.; Data security, authentication, and integrity are three important issues for secure data transmission. First of all, an efficient and secure password protocol is designed for data authentication. Unlike most of the existing protocols, the proposed protocol exploits a one-way hash function for authentication information exchange, which guarantees its security and efficiency. In order to further speed up the proposed protocol, we also design and implement a modified 128-bit one-way hash function, which is more suitable for the 16-bit fixed-point DSP platform. Secondly, several data encryption algorithms are studied and the Rijndael block cipher, which shows the best performance in the target DSP devices, is selected for data encryption/decryption. Thirdly, the Message Authentication Codes (MAC) approach is used to provide data integrity checking service, which can be applied to both data transmission and the synchronous changing of the user information (e.g. user password, secret key) at both sites (center and DSPs).; We also provide a circuit design for integrating the DSP and NIC (Network Interface card). Some selected TCP/IP protocols are implemented as well.; The proposed system has great uses in the application of emergency event handling services, such as the security monitor system, the medical care system, the data gathering system, and the intelligent building. |
