CSE 539
Applied Cryptography
Assignment 3
Answer all questions, be brief
Please submit hard copy. Typed preferred.
1.
a)
A general problem relating to hash functions is the following.
Suppose a hash function H, has an output range of n values (i.e. given an input, the output is one of n numbers). Suppose H is applied to k random inputs. What must be the value of k so that the probability that there is at least one collision, that is for some two inputs, x and y, H(y)=H(x) is 0.5?
2.
b)
Suppose the above hash function produces an m-bit output. What is
the value of k that so that the probability of collision is 0.5?
3.
a) Explain the structure of a digital certificate.
b) Who can be a certification authority?
4.
Explain the various techniques used by the antivirus software for the detection of the viruses.
5.
Explain the concept of biometric encryption and the problems associated with it?
6.
What is the principle of electronic voting method? What is the future of it?
7.
Suppose that Alice and Bob perform several rounds of the above scheme. Show that the identification scheme is flawed.