Answer the following problems

problem 1) This problem concerns main security goals (confidentiality, integrity, availability). describe a situation in which the goal of integrity is important, but there is not a need for confidentiality.

problem 2) In a particular form of two-factor authentication, a user shows their identity by providing a password and then receiving (on their mobile phone) text message with a number that should be entered as well. describe an attack that will succeed despite this particular two-factor approach.

problem 3) In the past few years, a type of scam has become common, where a telephone call claims to be from Microsoft Technical Support, telling customer that their computer has been infected by a virus, and offering to help fix the problem, see http://www.scamwatch.gov.au/content/index.phtml/itemId/792165. prepare the description appropriate for a friend who is not studying any computing courses, to help describe to them about the dangers of allowing remote access to a computer.

problem 4) If file permissions are set unsuitably, security could suffer. Assume Fred Foolish, a Chief Security Officer of the company you work for, makes a policy that every file should have its permissions checked by the system administrator. Discuss the impact of this policy on the likelihood or extent of damage caused by an attack, and on the normal work of the organization.

problem 5) A typical password is about 8 characters long (and so can be stored in 8 bytes, or 64 bits). Though, a typical key for encryption/decryption is much longer, and a key of 64 bits would not be considered secure. Describe this in terms of the difference between the way a secret is used as a password, and the way it is used as a key. what happens if the attacker takes few months to discover the secret?