Set the master key. There is one master key for each email account group. It is used to unlock the password safe for the acconts inside the group so that a user do not have to memorize or input the passwords each time he/she want to open his/her emailboxes. Each time when an email account group is created, a master key setting dialog box is shown asking the user to set the master key (see Fig: Setup the master). Since it is the only passphrase one needs to remember, make it sufficiently difficult for others to guess.