EFS galue e ala i le encrypting o se faila i se ki symmetric tele (iloa foi o le Faila Encryption Key, po o FEK), lea e faaaogaina ona e manaomia ai se aofaiga o taimi itiiti lava e encrypt ma decrypt aofaiga tele o faamatalaga nai lo pe afai o se asymmetric ki cipher o loo faaaogaina. O le ki symmetric e faaaoga e encrypt le faila ua lea encrypted ma se faila autu lautele e fesootai ma le tagata e faaaogāina o encrypted le faila, ma o lenei faamatalaga ua encrypted o loo teuina i se isi encrypted sui o le faila encrypted. Ae peitai, e mafai ona faaaogaina lenei ki e toe faaola ai le tagata e faaaogāina i le faiga faila NTFS, pe afai o loo i ai se isi tagata e faaaogāina ua fausia i le faiga faila o loo faaaogaina i le faiga o faamatalaga faalilolilo ma le toe faaleleia o faila. O le mea lea, e mafai ona faaaogaina e le tagata e faaaogāina mo le toe faaleleia o faamatalaga ua teuina i le faiga faila NTFS.
ki faaopoopo o le decryption