A free form string indicating the algorithm or tool used to encrypt the file system. If it is not possible or not desired ...

A free form string indicating the algorithm or tool used to encrypt the file system. If it is not possible or not desired to describe the encryption scheme (perhaps for security reasons), recommend using the following words: \"Unknown\" to represent that it is not known whether the file system is encrypted or not, \"Encrypted\" to represent that the file system is encrypted but either its encryption scheme is not known or not disclosed, and \"Not Encrypted\" to represent that the file system is not encrypted.