dropbearkey
Generate SSH keys in Dropbear format.
TLDR
Generate an SSH key of [t]ype ed25519 and write it to key [f]ile
$ dropbearkey -t [ed25519] -f [path/to/key_file]
Generate an SSH key of [t]ype ecdsa and write it to key [f]ile
$ dropbearkey -t [ecdsa] -f [path/to/key_file]
Generate an SSH key of [t]ype RSA with 4096-bit key [s]ize and write it to key [f]ile
$ dropbearkey -t [rsa] -s [4096] -f [path/to/key_file]
Print the private key fingerprint and public key in key [f]ile
$ dropbearkey -y -f [path/to/key_file]