network defense and countermeasure

1. In your own words, explain what a router does, why it’s an important component in network defense along with ways attackers try to compromise, exploit or break it.
(.75 Page) 2. Explain why encryption is such an important security tool. How does it help network defense and how can it hinder or limit packet filtering? (.75 Pages)
3. In your own words, explain and discuss at least 5 of the attacks discussed in the Modern Cryptanalysis Methods section of chapter 5 (pages 179 – 183). (1 Pages) 4.
Watch and summarize this video link https://www.youtube.com/watch?v＝Vd3tPqztUFY (.5 Pages) i download the pages for question#3