Lock the memory card
To set a password to lock your memory card to help prevent unauthorized use,
select Options > Set password. The password can be up to eight characters long.
The password is stored in your phone and you do not have to enter it again
while you are using the memory card on the same phone. If you want to use
the memory card on another device, you are asked for the password. To delete
the password, select Options > Delete password.