Debian provides the OpenBSD version of ssh by default. Because of the US export laws which prohibit the export of cryptography software, being classified as munitions, the ssh package cannot be part of the main Debian distribution. You will need to have a non-US distribution in your /etc/apt/sources.list file, such as one of the following:
deb http://non-us.debian.org/ unstable/non-US main contrib non-free deb http://ftp.au.debian.org/debian-non-US unstable/non-US main contrib non-free
Having made this addition you can update the information about available packages and then retrieve, unpack, and configure the package with:
# wajig update (apt-get update) # wajig install ssh (apt-get install ssh)
During the install you may be asked about installing ssh as setuid root. The suggestion from the configuration script is that you do not install as setuid root and if you have problems, then run dpk-reconfigure ssh to reconfigure the package.