What is the number of 6 character passwords containing the word "cyber"? (6 marks) 2. How many 6 character passwords are there which have at least 3 numbers? (6 marks) 3. Calculate the entropy of the

What is the number of 6 character passwords containing the word "cyber"? (6 marks)

2. How many 6 character passwords are there which have at least 3 numbers? (6 marks)

3. Calculate the entropy of the following systems and order them according to increasing security (6 marks, 2 marks each)

(a) A 6 digit PIN code with exactly 5 different numbers

(b) A 6 digit PIN code with exactly 4 different numbers

(c) A 9 character password with lower- and upper-case letters and numbers, where all the numbers are at the end.