Trucrypt can create an encrypted volume and a hidden volume within a file. Files can be copied to and from a mounted TrueCrypt volume just like they are copied to/from any normal disk.
Install from a ppa
sudo add-apt-repository ppa:michael-astrapi/ppa sudo apt-get update && sudo apt-get install truecrypt
To remove it
sudo apt-get install ppa-purge sudo ppa-purge ppa:michael-astrapi/ppa
Or install from file
Download x86 version
wget http://www.truecrypt.org/download/truecrypt-7.1a-linux-x86.tar.gz
Download x64 version
wget http://www.truecrypt.org/download/truecrypt-7.1a-linux-x64.tar.gz
Extract the file truecrypt-7.1a-linux-x86.tar.gz or truecrypt-7.1a-linux-x64.tar.gz in the same directory
tar xzvf truecrypt*.tar.gz
To install trucrypt x86
./truecrypt-7.1a-setup-x86
To install trucrypt x64
./truecrypt-7.1a-setup-x64