e4crypt

» /tmp/hi$ e4crypt add_key
Enter passphrase (echo disabled): 
Added key with descriptor [e5f00c49402965f9]
Added key with descriptor [082a7d65fcadaa7e]

» /tmp/hi$ e4crypt set_policy e5f00c49402965f9 test
Key with descriptor [e5f00c49402965f9] applied to test.

» /tmp/hi$ cd test

» /tmp/hi/test$ echo foo > bar

» /tmp/hi/test$ cat bar
foo

» /tmp/hi/test$ cd ..

» /tmp/hi$ keyctl show @s
Keyring
[…]
 533902646 --alsw-v   1000  1000   \_ logon: ext4:e5f00c49402965f9

» /tmp/hi$ keyctl unlink 533902646
1 links removed

» /tmp/hi$ ls test
bar

» /tmp/hi$ cat test/bar
foo