Challenge 33-35

[seemenkina]

Start tests file for DH attack from challenge 5 (33-35)

Test to check the implementation of DH algorithm

$ go test ./set5 -run TestDiffieHellman TestDHEncrypt
$ go test ./set5 -run TestDHEncrypt

Test to check the implementation a MITM key-fixing attack on Diffie-Hellman with parameter injection

$ go test ./set5 -run TestDHAlgEva_MITMAttack

Test to check the implementation DH with negotiated groups, and break with malicious "g" parameters

$ go test ./set5 -run TestMITMAttackG