Problems Installing Dukto?

Dukto is not in the regular Ubuntu repositories.

Download it at the home page at http://www.msec.it/blog/?page_id=11

The direct Ubuntu download is at https://software.opensuse.org/download.html?project=home:colomboem&package=dukto

Update #1:

Did you follow these instructions?

sudo sh -c "echo 'deb http://download.opensuse.org/repositories/home:/colomboem/xUbuntu_16.04/ /' > /etc/apt/sources.list.d/dukto.list"
sudo apt-get update
sudo apt-get install dukto

If that didn't work, then do this...

Download the file here...

http://download.opensuse.org/repositories/home:/colomboem/xUbuntu_16.04/amd64/dukto_6.0-1_amd64.deb

And assuming that the .deb file went to your Downloads folder, install it with...

sudo dpkg -i ~/Downloads/dukto_6.0-1_amd64.deb