1. Decrypt the message fqenjxpno fv rtnffrz fvug, which was encrypted using ROT13.
2. Prove, using only the definition of congruence modulo n, that if a ≡ b (mod n) and b ≡ c (mod n), then a ≡ c (mod n).
3. What does this list of instructions do? Comment on whether it is an algorithm and whether it terminates.
1. Let n = 3.
2. Replace n with n+4.
3. If n is even, go to step 2.