Encrypting File System (EFS)

Definition - What does Encrypting File System (EFS) mean?

The Encrypting File System (EFS) is a functionality of the New Technology File System (NTFS) found on various versions of Microsoft Windows. EFS facilitates the transparent encryption and decryption of files by making use of complex, standard cryptographic algorithms.

The cryptographic algorithms are used within EFS to provide useful security countermeasures, whereby only the intended recipient can decipher the cryptography. EFS uses symmetric and asymmetric keys during the encryption process, but it does not protect data transmissions. Instead, it protects the data files within systems. Even if someone has access to a certain computer, whether authorized or not, they still won’t be able to unlock the EFS cryptography if they don’t know the secret key.

Techopedia explains Encrypting File System (EFS)

EFS is actually a transparent public key encryption technology that operates together with NTFS permissions to allow or deny user access to files and folders in various Windows operating systems, including NT (excluding NT4), 2000 and XP (excluding XP Home Edition).

Some of the key features of EFS are as follows:

  • The encryption process is easy; simply select the check-box in the file or folder's properties to turn on the encryption.
  • EFS offers control over who can read the files.
  • The files selected for encryption are encrypted once they are closed; however, they automatically become ready to use once they are opened.
  • Remove the file's encryption feature by clearing the check-box in the file's properties.

Many companies use EFS, but it must be used with caution and knowledge so as to avoid encrypting content that should be transparent rather than secure. This is compounded by the fact that it may be difficult to decrypt data content that was not meant to be encrypted in the first place.

EFS developers remind users that once a folder is marked to be encrypted, all files contained in that folder will be encrypted as well, including future files that are transported to that particular folder. However, a custom setting for encrypting “this file only” is available.

Encryption passwords are identity-specific, so it’s important for employees to avoid sharing their passwords. It’s equally important that users remember their passwords.

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