http://l3tczdiiwoo63iwxty4lhs6p7eaxop5micbn7vbliydgv63x5zrrrfyd.onion/user-manual/howto.html
You should set the appropriate validity
period based on your needs. A shorter validity makes your system more secure (it doesn't hurt that long if the
key gets lost to an attacker), but if the certificate expires before you have replaced it with a new one in
Privoxy and in all browsers, the communication will fail.