CS 472

Assignment #4

Due Midnight, Thursday Oct 29, 2009

Message Digest can be used for:

A. Encryption as described in generating onetime pad.

I have used our beloved password to generate a onetime pad based on md2.

Then I used the crypto program to encrypt a plainfile to produce a cipherfile and then converted it to a cipherfile.base64.

You are required to find the plainfile.

B. MAC as described in computing a MAC.

I have Prepended our beloved password to a file F and computed the MAC using md2:

Which file, File1 or File2, is the original unmodified file F?

Submit your answer as described in Assignment #2 (but replace A1 with A4).

A shell script is used to grade the assignment & it is case and name sensitive.