Is file encrption different from content encryption

Question

Is there any difference between encrypting a file and encrypting the content of the file. If so, how to do the both.

Answer 1

There is no difference.

Answer 2

There is no difference; however, it is possible to go an extra step by mapping the name of the file to something completely meaningless (EncFS does this in paranoia mode) or by attempting to hide the encrypted file is some way (maybe as diffused bits in some other media file). However, those aren't really encryption, but rather steganography -- attempting to hide important (usually encrypted) information.

Answer 3

File encryption is encrypting a whole file, from the outside (e.g. by right-clicking in Windows XP Explorer). Content encryption is generally used as a synonym for file encryption, but the two things are different. Content encryption means encrypting the contents of a file, or part of the contents of a file.

Consider video streaming. For instance, we might want to encrypt an HD video so that anybody can see the low-res version but only paying subscribers get the top quality stream. We cannot do that by encrypting the whole video file.