00500nas a2200085   4500000000100000008004100001245005200042856008900094520023100183       2008                            d00aCyber Security Basic Defenses and Attack Trends  uhttps://people.eecs.berkeley.edu/~sastry/pubs/Pdfs%20of%202008/CardenasCyber2008.pdf3 aA systematic study of the security of any system requires the description of three concepts: the security goals we want to achieve, the threats we expect to face, and the mechanisms and tools we can use to protect the system.