Published: 02-04-2019 | Author: Remy van ElstText only version of this article
Dropbear is a lightweight SSH server and client implementation, often used on embedded systems and routers. If you use the dropbear SSH client (dbclient) and want to use a private key, it needs to be in the dropbear format and cannot have a passphrase. Dropbear provides a conversion utility to convert openssh style keys to dropbear style keys, dropbearconvert, but on Ubuntu it's not in your $PATH. This means you have to provide the full path to execute it, which is cumbersome. There is a bug in Ubuntu that has been reported in 2012, but in Ubuntu 18.04 (2019) it's still not fixed.
This is the full path to dropbearconvert:
This is an example to convert an OpenSSH style private key to a dropbear style private key:
usr/lib/dropbear/dropbearconvert openssh dropbear ~/.ssh/id_rsa ~/.ssh/id_rsa_dropbear
Your dropear style private key will be located
Do note that your private key cannot be protected with a passphrase. Dropbear does not support this.