Design and Investigation on Image Transmission in Multi-User Cross-Layer Security Network

A multi-user cross-layer security network based on optical code division multiple access (OCDMA) and algorithmic cryptography is proposed, and its security performance is analyzed quantitatively for the first time. In this scheme, eavesdroppers have to not only intercept the optical code of OCDMA in physical-layer, but also break the algorithmic cryptography in data-layer. Thus, the information security will be enhanced effectively. Synchronous transmission system and asynchronous transmission system are analyzed respectively. It can be seen that the cross-layer security of asynchronous transmission is far greater than that of synchronous transmission when the number of users is large enough. OptiSystem simulation is used to investigate the image transmission in cross-layer security system. The transmission distance of single mode fiber is 100 km, and transmission rates are 10 Gbit/s and 1 Gbit/s respectively. It can be seen that legitimate user can recover original image correctly with matched decoder and correct encryption algorithm. However, eavesdroppers cannot recover the image correctly with matched decoder/wrong encryption algorithm or unmatched decoder/correct encryption algorithm. Therefore, our scheme can greatly enhance the security of image transmission system.