16. The government of Malaysia, does not want its citizens (users) to access certain type of content (forbidden websites) on the Internet. The government is in a position to deny users access because it controls all the Internet Service Providers (ISPs) in Malaysia. An independent, international organization is fighting for freedom of speech, OfFoS, wants to help the users in Malaysia to circumvent these restrictions. A group of OfFoS volunteers is preparing a report describing the technical measures used to deny access that the ISPs of Malaysia are employing. The report also contains a list of potential countermeasures. However, as these volunteers lack expertise in the topics of computer network and security, you have been asked to review the report. The report identifies two threats:

Threat 1 : The ISPs can block access to forbidden content. Threat 2: The ISPs can detect and identify users who attempt to access forbidden content (allowing the government to persecute them). The report also states that: The ISPs keep track of a blacklist of websites providing forbidden content (domain names and IP addresses). The ISPs keep track of a blacklist of words specific to forbidden content. OfFoS has the resources to deploy a limited number of machines (outside of Malaysia) to assist the users. Based on the hypothetical situation above, answer the following questions (5 marks). a) How can the ISPs take advantage of this to achieve Threat 1? b) Which protocol is responsible for providing the IP address of Domain Name Service (DNS) servers to the users? c) Propose ONE (1) simplest way for the users to circumvent/avoid this blocking mechanism. d) Assume that the countermeasure proposed above is deployed. The DNS queries and replies are sent out without any cryptographic protection. Discuss on how the ISPs can take advantage of that to achieve Threat 1 and Threat 2.