Assume that A and B share a long-term 256-bit AES key K. Our key exchange protocol has two goals: (1) let A and B agree on a new fresh session key Ks to be used for a current session, and (2) perform mutual authentication. Nb is a nonce and Ks is a new session key generated by B. Assume that Ks and Nb are of the same bit-length and both are always chosen at random. EK(.) denotes AES encryption of everything inside () with key K. HMACK(.) denotes SHA2-based HMAC of everything inside () using key K. Protocol:
1.A −→ B: EK(A, B, "Hello")
2.B −→ A: EK(Ks, Nb, HMACK(A, B, "Hello"))
3.A −→ B: HMACK(Ks, Nb, 1)
What (if any) are the vulnerabilities of this protocol? If there are any, how can you fix them? For fix, you need to show modification of the protocol. Limit each answer (vulnerabilities and their fixes separately) to 10 lines

Two technicians are discussing the common u-joint. technician a says its input and output speeds should be equal. technician b says that it normally has two yokes. which technician is correct?

This first part of the film shows the early history of motion pictures. how accurate do you think the portrayal of the early motion picture industry is? why? is historical accuracy important in films and theatre productions? explain. in the scene where don is going to the party (starting at time code 14: 51), we see a street scene as he first rides with cosmo and then with kathy. what aspects did the filmmaker include to make the scene look and feel like don, cosmo, and kathy are riding in a car on a street? think about elements such as scenery, sound, props, lighting, and so on. a "talkie" picture is shown starting around time code 21: 15. how does the audience in the film react to the "talkie"? what influence do audiences have on film and theatre performances? how do film and theatre actors influence audiences? in the musical scene with cosmo (starting at time code 27: 00), how does the actor use props? what is the result? do you think the use of props effectively fulfilled the artistic vision for this musical number? why or why not?

Which option should u select to ignore all tracked changes in a document