Authentication is performed on a plurality of links coupling one node of the computing environment and another node of the computing environment. The performing authentication includes obtaining by the one node a shared key from a key server coupled to the one node and another node of the computing environment. A message encrypted with the shared key is sent from the one node to the other node via one link of the plurality of links. An indication that the other node decrypted the message using the shared key obtained by the other node is received from the other node via the one link. The sending and the receiving are repeated on one or more other links of the plurality of links using the shared key previously obtained.