There is a risk, multidimensional and serious, growing as companies become more dependent on networking and distributed systems. 20.1 Security Threats Passive attacks - eavesdropping, monitoring transmissions. Active attacks - modification of transmitted data and attempts to gain unauthorized axcess to computer systems. Eavesdropping can occur if hackers monitor the traffic on the LAN and capture traffic based on source and destination addresses. Routers or communications servers to the outside world present a point of vulnerability.
Wiring closet is vulnerable.
B. Data Encryption Standard - most widely used encryption scheme. Inputs - plaintext and the key. Strength of DES - 1. cryptoanalysis has not been successfully performed on the algorithm, as yet. Based on math functions rather than on simple operations on bit patterns. Assymetric - involves use of two separate keys, which improves confidentiality, key distribution, and authentication.