encryptionmacostruecrypt
I'd need to create an encrypted volume on my MacBook Pro running OS X El Capitan.
It's been a while since I needed to do something like that, I think it was 2010 when I used TrueCrypt.
I know that nowadays its development has been suspended or somehow discontinued, so I was wondering: how to have an encrypted volume with TrueCrypt-like level of security on Mac OS X?
You could use the recovery option of Disk Utility:
This of course requires source and target disk to be identical, but the same restriction applies to dd and similar tools.
Usual warnings concerning picking the right disk as source etc. apply!
I would guess that the weakest link isn't the choice of formats, but your picking a decent password and not letting it get observed or captured.
In the general case where there is a system tool and a third party one, I usually start with the tool that is built in until I have good, definite and enumerable reasons to not use the default tool.
Go with encrypted disk images in the case you have set out.
Best Answer
VeraCrypt
If you want operating system independence, e.g., a thumb drive that you can use on systems other than macOS, you might want to look at VeraCrypt - the successor to TrueCrypt. VeraCrypt is open source as well. Further information can be found in Encrypt FAT USB drive under El Capitan.