Consider a password system that uses password hashing for password verification. Each password consists of a string of 4 digits: (a3 a2 a1 a0), that is each ai can be a digit {0,1,2,...,9}. Soa0represents the rightmost digit, while a3is the leftmost digit in the password. The hash function is defined as: h(a3 a2 a1 a0 )=(a3^4 +a2^3 +a1^2 +a0 )mod 100

where mod 100 is the remainder of integer division by 100.

A)Suppose an attacker wants to access Johns account using an online attack. What is the probability the attacker will guess Johns password if no hashing is involved, and when hashing is involved?

B)Suppose the password system is used with a 2 digit salt(s1 s0).The salt will be simply added to the hash value (integer addition) and ( mod 100) operation will be used to make it into a 2 digit number. In other words, the hash function is now: h(s1 s0 , a3 a2 a1 a0 )=(10 s1+s0+a3 4 +a2 3 +a1 2 +a0 )mod 100 For example, the hash for password 2745 given salt 39 is: h(39,2745) = (39 + 2^4 + 7^3 + 4^2 + 5) mod 100 = 19. Explain how adding salt affects the chance of success for an attacker who tries to guess the password. Explain your answer using the password 7819.