CipherShed is based on TrueCrypt and is still a fairly new project aiming at
replacing the entire code base currently licensed under the proprietary
TrueCrypt license and migrate to a free software license like the GPL:
https://wiki.ciphershed.org/License
There is another similar project called VeraCrypt, but the main author
doesn't care about licenses and freedom (as he states in this interview:
https://twit.tv/shows/floss-weekly/episodes/340), so I'd stay away from both
at least until CipherShed has replaced the code base.
If you need a free/libre program similar to TrueCrypt, use for example the
GPL licensed zuluCrypt: http://mhogomchungu.github.io/zuluCrypt/
