A public key encryption system for defective data transmission

The paper describes an encryption system developed in a project oriented study course in the fall of 1997 at Linkoping University, Sweden. The course assignment was to develop a short-range wireless communications system for simplex transmission of video data, e.g. from a surveillance camera. The encryption system was part of this system. Radio sender and receiver hardware were provided while software was developed on Sun Sparc computers. The goal was to create a system capable of continuous real time operation. Requirements were that the communications channel should provide confidentiality as well as authenticity of the video data, thus requiring cryptography. The main challenge was to design an encryption system that propagates as few errors as possible which are introduced by radio transmission. The developed encryption system uses RSA for encrypting session keys and an alternating stop-and-go stream cipher for bulk data encryption