Dropbear is a small SSH server and client written by Matt Johnston

https://matt.ucc.asn.au/dropbear/dropbear.html

By default SliTaz will not start the SSH server at boot. To be launched automatically, dropbear must be added to the variable RUN_DAEMONS in the /etc/rcS.conf file. (Normally Dropbear logs in /var/log/messages, but in SliTaz it logs in /var/log/auth.log)

More info: http://doc.slitaz.org/en:handbook:ssh

A good doku of dropbear is on OpenWRT - http://wiki.openwrt.org/doc/uci/dropbear