Let's compare encfs with a simple file encryption
Encrypt a file using openssl
openssl enc -aes-256-cbc -salt -in file.txt -out file.enc
- the contents of file.txt get read exactly once.
- the contents of file.enc get written exactly once.
- a directory entry for file.txt is removed
(you probably want to securely wipe file.txt but I'll skip that)
Encrypt a file using encfs
cp /normal/file.txt /encrypted/file.txt
- the contents of /normal/file.txt get read exactly once.
- the contents of /encrypted/file.txt get written exactly once.
- a directory entry for /normal/file.txt is removed
There's no scope for reducing the amount of IO