I have several hundred gigs of data that I store on a NAS for my own usage. The NAS storage solution manages local encryption, however I am looking into cloud backup solutions for disaster recovery. To that end, I am looking for a way to create a bulk file container (like a zip or tarball) and a piece of software that will let me encrypt said container using a keypair.
I am looking for a solution that meets the following requirements:
- Cryptographically secure (obviously)
- Able to handle large input files; the data in question is many hundreds of gigabytes with individual files as large as 50GB
- Can output a single, portable, file container for easy upload
- Has the option to use a key file for encryption
Note: something like Vera/Trucrypt's encrypted volume containers already occurred to me. The problems are twofold:
- A portable volume file cannot grow/shrink to fit my data
- I am looking to encrypt existing data so I don't want my backup utility to have to first decrypt a portable volume, copy data to it, then re-encrypt it for upload
EDIT: As an alternative, maybe I am off-base and using a key file doesn't get me any more security than a good implementation and strong passphrase. If that's the case, I'd love to learn why.