If you install OpenSSH, you need to change your device's root password to prevent the possibility of unsavory people remotely logging into your device using the default password.

Option A: Open Terminal on your desktop and log in over wifi

Or Option B: Open a SSH client app

To configure your client app on your device: add "127.0.0.1" (which means localhost) as the host/server, "root" as the login username, and "alpine" as the initial password.

Or Option C: Open MobileTerminal

1: Obtain Administrator Access

Note: this first step is only necessary if you are using MobileTerminal. If you logged in via SSH as root, you do not need to do this step, so skip to Step 2.

Run "su root" and provide the root password. The default password as provided by Apple is "alpine".

Here I also run "cd" only to shorten the otherwise very long prompt.

iPhone:~ mobile$ su root
Password:
iPhone:/var/mobile root# cd
iPhone:~ root#

2: Change the root Password

Run "passwd" and type in your new password twice. Please note that your keypresses will not be displayed on the terminal screen (for security).

iPhone:~ root# passwd
Changing password for root.
New password:
Retype new password:
iPhone:~ root#

3: Change the mobile Password

This is the regular user account on the device. Run "passwd mobile" and repeat as directed above.

iPhone:~ root# passwd mobile
Changing password for mobile.
New password:
Retype new password:
iPhone:~ root#

4: Close your terminal

Congratulations! Your job is done!