ABSTRACT:

Data communications systems normally use combinations of transmission links for sending messages. Tapping risks of transmission links are discussed. Although fiber optics provides the highest level of interception protection among all links, tapping methods and countermeasures are available. Effective encryption systems should be used for securing highly sensitive messages traveling over links. Link, end-to-end, and public key encryptions may be used. Algorithm strength and key management of encryptions are both critical.