一种改进的DCSK保密图像传输方案

A Secure Image Transmission Scheme Based on Improved DCSK

差分混沌键控(DCSK)采用非相干解调技术,不必在接收端生成混沌同步信号,结构简单,并具有很好的抗噪性能,但保密性不足,较易破解。针对DCSK保密性差的问题,提出了一种改进的DCSK方案,在保证其性能的同时大大提高保密性。且对此系统进行了深入的理论分析,对误码率、扩频系数和信噪比之间的关系进行了深入研究,并将其运用到图像保密传输中,通过仿真验证该方案的可行性。仿真结果表明,改进的DCSK系统在误码性能和保密性上都较原系统有极大提高,因此对实际应用具有重大意义。

Non-coherent demodulation technology is applied in the differential chaos shift keying （DCSK） and it＇s unnecessary for the receiver to generate chaotic synchronous signals at the receiving end. The structure in DCSK is simple and has good performance in anti-noise. However, it is lack of performance in security, and easier to be cracked. A modified DCSK scheme was proposed for the security problems caused by the traditional DCSK scheme. It retains the good performance of the old one and greatly increases security performance at the same time. The theoretical analysis toward the system was deeply carried out. The relationship among the BER, the frequency spread factor and SNR were also deeply analyzed. Finally, it was applied in an image transmission system as an example. The simulation results indicate that the performance of the bit error ratio （BER） and security are greatly improved. The feasibility was also proved by simulations.