In the SSH algorithm negotiation phase, the SSH server and client exchange the list of algorithms that hey support. The list of symmetric encryption algorithms of the SSH server is as follows: aes256-ctr, aes192-ctr, aes128-ctr, and aes256-cbc. The list of symmetric encryption algorithms of the SSH client is as follows: aes128-ctr, aes192-ctr, aes256-ctr, and aes256-cbc. Which of the following symmetric encryption algorithms can be used by both the SSH server and client?
The symmetric encryption algorithms that can be used by both the SSH server and client are those that appear in both lists. In this case, the algorithms that match are aes256-ctr, aes192-ctr, aes128-ctr, and aes256-cbc. Therefore, all the provided options are correct.
Encryption_algorithms A name-list of acceptable symmetric encryption algorithms (also known as ciphers) in order of preference. The chosen encryption algorithm to each direction MUST be the first algorithm on the client's name-list that is also on the server's name-list. If there is no such algorithm, both sides MUST disconnect.