113 In shared secret cryptography there are various possibil

(11.3) In shared secret cryptography, there are various possibilities for forming a session key. Remember that R is the challenge sent by Bob to Alice, and A is Alice\'s secret, which Bob also knows. Which of the following are secure for a session key?

Solution

A o R is not secure
{R + A}A is secure
{R}R+A is secure
{A}A is not secure

Hence option 1 and option 4 are secure for session key with the given condition.