i own a small private server (@home) with all necessary features for my backup purposes (Owncloud, SVN, GIT).
My target now is to ensure the safety of my data in emergency cases like fire/flood. For this i want to rent or use a free online cloud storage (dropbox,strato,...). My server should backup there all important data on a weekly basis. Sadly the CPU, older Atom dualcore, has not enough performance to work on heavy load tasks.
Which file format or technique should i use to upload the data in a way no other system can read it? I thought about implementing an own small crypt software for it but at first i want to here your comments.