Memoir offers 128-bit AES encryption for keeping your data private. This functionality is enabled by locking the entries you would like encrypted. To lock an entry, select the entry, then click the "Add Lock" menu item under the "Entry" menu. Or, select the entry (or entries) in the Entry List view, and right click on one of the selections and choose "Add Lock".
The first time a lock is added to Memoir, a sheet will appear asking you to set up a new password (shown above). Each entry that you add a lock to will share this password. To lock all entries in Memoir, select a locked entry and choose "Lock" under the "Entry" menu. Or, right click the entry in the Entry List view and select "Lock". All entries with an associated lock will be encrypted, and the locked entries will be removed from all search indexes. To unlock the entries, simply select a locked entry in Memoir and choose "Unlock" under the "Entry" menu (or right click the entry in the Entry List view and select "Unlock"). A locked entry will display a locked message in the Entry view, and allow you to enter the password there to unlock the entry.
Changing the lock password is straightforward, just open Memoir preferences by selecting "Preferences..." in the Memoir menu. A window will show similar to the one below. Clicking the "Change Password..." button will allow you to enter the old password for the locked items, along with the new password. Once you select a new password, all locked items using the old password will now use the new password.