After I encrypted my phone, I hated typing in the long password every time. I don’t mind typing it in once when the phone boots, but every time I take the phone from my pocket, I am forced to enter this long, secure password. I know this kinda defeats the whole purpose of the encryption system since it makes the whole thing easier to attack via brute force, but I figured it’s better to have an encrypted phone with a somewhat weak password, than to simply rely on a screen lock.
This command requires you to have root access (you ‘rooted’ your phone) and have a terminal emulator installed.
Open your terminal emulator and type:
su
so that you enter the Super User mode. (Super User = Root user with root permissions)
The command to change the encryption password is:
vdc cryptfs changepw <new_password>
where <new_password> is the password you choose for the actual encryption, and you will be required to enter at boot time.
Now you are able to go into the main Android settings and go into security, and set the screen lock password. Now the device will let you type a password as short as 4 characters with at least one number.
So in effect you just have to enter a pin to unlock the screen, but the encryption is still locked with more secure password.