If you want to share data with collaborators, you might want to put a password-protected zip file on the web for them to download.
If you have data in a Linux directory mydir, you can create a tar file of that directory using:
% tar cvf mydir.tar mydir
If you have 7-zip installed, you can then create a password-protected zip version of mydir.tar by typing:
% 7za a -tzip -pMYPASSWORD -mem=AES256 mydir_secure.zip mydir.tar
where the password is set to 'MYPASSWORD'
If you collaborator has 7-zip installed on a Linux machine, the zip file can be unzipped using:
% 7za e secure.zip
This will ask for the password to be entered.
I haven't tested it, but I'm guessing that your collaborator could also unzip the file using 7-zip on a Windows machine.
Thanks to this handy webpage for information: http://xmodulo.com/2013/09/how-to-create-encrypted-zip-file-on-linux.html