Updated Sunday, January, 24 2013, trying to address all issues raised in the comments below.
I have used Android QuickSSHd in the past to connect my Android devices with my Linux desktop. Since I installed CyanogenMod 10.1 nighty builds on them, none of the known SSH apps seem to work anymore. The Cyanogen wiki has a page about how to setup the Dopbear SSH daemon, but also states that since CynogenMod 9.x it is no longer included.
Apparently the original OpenSSH_6.0p1 is included with Android 4.2.1 (JellyBean) although it is not configured
and support for sftp is missing. Here is what I did to have it up and running.
To gain root access on a Android phone, we need to replace the default operating system kernel, which is an important part of the phone firmware and normally installed by the manufacturer of the phone. The custom Kernel will allow us to access the phone as administrative user (root). Custom kernels usually also provide other enhancements, like additional functions, optimized speed. Continue reading
With a SSH daemon running on your phone, you can have a secure encrypted connection to you phone and work on the phone over the network as with any other Unix or Linux system. Secured with your personal SSH-keys. Continue reading