Questions 1. In symmetric key cryptosystem, assume that Alice and Bob have set up a common key Kab This key is only known to Alice and Bob. (la) Can we achieve data origin authentication? (lb) Can we achieve non-repudiation? 2. When logging into a computer, password is for 3. Give me an example in which "attack technology" is used for good purpose. Questions 1. In symmetric key cryptosystem, assume that Alice and Bob have set up a common key Kab This key is only known to Alice and Bob. (la) Can we achieve data origin authentication? (lb) Can we achieve non-repudiation? 2. When logging into a computer, password is for 3. Give me an example in which "attack technology" is used for good purpose