The Nessus Security Scanner protects the communication between the client and the server by using SSL. To work securely, the OpenSSL library needs a suitable amount of random bytes. On most system, it uses EGD or /dev/random (or /dev/urandom).
On systems which have none of these, Nessus will provide OpenSSL with a file full of random bytes generated by nessus-mkrand which is stored by default under $HOME/.rnd. nessus-mkcert and nessus-mkcert-client require user input as a random seed.
By default, nessus-mkrand produces a file stored under $HOME/.rnd containing 1024 bytes of entropy.
nessus-adduser(8), nessusd(8), nessus(1), nessus-mkcert(8), nessus-mkcert-client(1), openssl(1)
nessus-mkrand was written by Michel Arboi <email@example.com>.