I have a large set of files on Cloud1 (which does not provide snapshots or its own backup/rollback features). My local desktop syncs files on an as-needed basis (and the quantum of files on Cloud1 exceeds the local disk space on my local desktop).

I would like to maintain a one-way backup solution on Cloud2. I would like this to be encrypted and incremental.

What are some open-source software solutions to achieve this?

  • Can you mention the cloud provider ot the sync software you are using? This website is for giving "Software recommendations", and I cannot give you software recommendation if I don't know the software you are using Mar 11 at 8:11
  • I mean, I could suggest you to use Data Sync if you want to do that from AWS to Azure. It's one-way, encrypted and incremental. But I need to know the cloud provider and the software you are using currently Mar 11 at 8:13
  • I was looking for general advice that may not be specific to a given cloud provider. But some examples I am using/considering: from iCloud/ProtonDrive to OneDrive (or something cheaper like Amazon Glacier or iDrive). Possibly with Cryptomator on source and/or destination - or some other way to ensure the destination is encrypted for long-term backup/archive.
    – kmccoy
    Mar 12 at 14:23
  • Just another question: is this for work or for private life? Do you need encryption for yourself or you have to provide security for your customers and respect security policies like SOC2 or ISO27000? Mar 12 at 19:32
  • And size of the data? Like 10.000 family pictures or 2Tb of files for my customers? Mar 12 at 19:33

1 Answer 1


All cloud providers says that their storage are encrypted and private.

I never heard a cloud provider that says: "We keep your file unencrypted and not in a safe place and even our employees can see your files.". You will never hear a cloud provider saying that.

This means that you always have to trust the cloud provider, whatever that is American, European, Chinese or Russian. We will never know if the cloud provider doesn't spy on the files. Deal with that.

Frankly I would do this:


  1. Local Backup: Buy a Synology NAS and keep a sync between your computer and the NAS. The NAS can store multiple disks and several terabytes. The NAS itself provides a software for the sync. This way you are safe and you are sure that your files are encrypted and stored in a safe place
  2. Cloud Backup: The Synology NAS provides a software for the sync of the data from the NAS to the main clouds providers (AWS, Azure, Google and many more). But we don't trust the cloud providers! So what we are going to do is this: on the NAS we are going to have an internal backup. Let's say that all your files are on disk1, you back up them on disk2 and you zip them in a unique file and encrypt it. Then you sync that file to your favorite cloud provider
  3. Disaster recovery: now you create a sync between Cloud1 and Cloud2. I think you are going extra far with this level of security and is going to be so expensive that not even corporation do that. Keep in mind that storing your files on AWS is already safe enough. If you store your files at AWS in Dublin the files are already replicated 3 times in 3 different zones around Dublin. This means that in case one of the datacenter is destroyed by an asteroid you still have 2 copies of your files in Dublin. Then in case there is a nuclear bomb that hits Dublin your file is also replicated in India. Then you don't feel safe enough you can also organize a replication from AWS to Azure but I think that in case of an alien civilization invading our planet your file might be safe but by that time you will have other problems than the encryption of your family pictures.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.