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 k, to be used for a current session, and (2) perform mutual authentication. n, is a nonce and k, is a new session key generated by b. assume that k and nb are of the same bit-length and both are always chosen at random. ex( ) denotes aes encryption of everything inside ) with key k. hmack denotes sha2-based hmac of everything inside ) using key h 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? and, how can you fix them? again, keep your answers limited to 8-10 lines.

This assignment continues work on the online booking facility introduced at the end of chapter- 10. the work will be continued in the assignments for chapters 14 and 15 (a) assume that you will produce your online booking facility using an agile approach. i. suggest the kind of user research you would like to conduct for your product before iteration cycles begin. ii prioritize the requirements for your product according to business value, i. e which requirements are likely to provide the greatest business benefit, and sketch out the ux design work you would expect to undertake during the first four iteration cycles, i. e. cycle 0, and cycles 1 to 3. (b) using one of the mockup tools introduced above, generate a mockup of your product's landing page, as developed in the assignment for chapter-11 (c) using one of the patterns websites listed previously, identify suitable interaction patterns for elements of your product, and develop a software-based prototype that incorporates all the feedback and the results of the user experience mapping achieved at the end of chapter-11. if you do not have experience in using any of these, create a few html web pages to represent the basic structure of your website