Quick and easy way is to
compress and then
tar cfj safe-archive.tar.bz2 Directory/
# will ask you an 8 char password twice to lock it up.
# But, remember to delete your Directory after this,
rm -rf Directory/
# And, I hope you don't forget the password, or your data is gone!
safe-archive.tar.bz2.bfe -- which you can rename if you feel paranoid about it.
To open the encrypted pack,
bcrypt safe-archive.tar.bz2.bf3 # Or, whatever you called it
tar xfj safe-archive.tar.bz2
# And, your directory is back!
If you are ready to get more messy, I'd suggest
truecrypt, and making encrypted volumes.
But, I don't think that is necessary for regular data (like not related to national security, say).
ps: note that I am not suggesting bcrypt is weak or incapable of national security in any way.
Reply to the comments on my answer above.
I tried to give a simple answer -- and, I do agree that my choice of not suggesting Truecrypt as the first option may be inappropriate to some here.
The question asks for an easy way to encrypt a directory.
My measure of security here is based on two things,
- What do you want to secure and
- Who do you want to secure it from
I rate this as the level of your 'paranoia'.
Now, without saying Truecrypt (or other similar methods) are costlier,
all I want to say is, a bcrypt sequence run in tmpfs is sufficient for your daily use today
(it won't be so, probably, in about a decade, I guess, but it really is for now).
And, I also assume that the value of data being secured here is not going to be comparable for a mona-lisa class 'recovery' attempt.
Simple question then -- do you expect someone to try grabbing your powered-off laptop and attempt recovering data from its cold RAM space?
If you do, you probably ought to reconsider your hardware and software in the first place, check which ISP you connect to, who can hear your key-presses, and so on.
ps: I like Truecrypt and use it. The OSI compliance, or lack of it, does not really matter. And, I am not staging
bcrypt and the scheme proposed here in competition to it.