SimpleSSHD is a free and open-source SSH server that is based on Dropbear and is compatible with Android devices. It supports scp, sftp, and rsync protocols for secure file transfer. The server only supports public-key based authentication, making it secure and reliable. It does not use root, which means it must listen on a port overdefaults to port 2222).

The interface is simple and easy to use, making it a great option for users who want to securely access their Android device remotely. The absence of ads is also a plus, as it ensures an uninterrupted user experience. With its robust security features and open-source nature, SimpleSSHD is a must-have utility for anyone who wants to securely access and transfer files on their Android device.