Dropbear
Dropbear is a relatively small SSH 2 server and client. It runs on a variety of POSIX-based platforms. Dropbear is open source software, distributed under a MIT-style license. Dropbear is particularly useful for "embedded"-type Linux (or other Unix) systems, such as wireless routers. 'http://matt.ucc.asn.au/dropbear/dropbear.html'
Enabling dropbear
How to enable Dropbear server
1-Open sdk configuration system
$ make config
2- Enable Dropbear server:
-> File System Configuration -> Select target's file system software [*] dropbear-0.52 (SSH Server)
3- When you check Dropbear server, you can enable scp and ssh
-*- dropbear-0.52 (SSH Server) [*] Enable dbclient (SSH Client) [*] Enable scp
Commands to use ssh
$ dbclient user@host
Commands to use scp
$ scp <file> user@host:/<location>
Setting keys to get ssh connections without password requests
How to get public and private keys of Dropbear in the target
How to set public key of Dropbear in the host
How to get public and private keys of OpenSSH in the host
How to set public key of OpenSSH in the target
Commands to use ssh without password request
$ dbclient user@host -i /etc/dropbear/dropbear_rsa_host_key
Commands to use scp without password request
$ scp <file> user@host:/<location> -i /etc/dropbear/dropbear_rsa_host_key