Client-side encrypted online backup service

Question

I'm very interested in using an online backup service to keep my data safe from malfunctioning hardware. And I am, of course, willing to pay for the service.

However, I don't want my data to be accessible by anyone other than me - and that's including the backup service itself. The online backup services I've seen do seem to use strong cryptography for the connection to their server, and keep the data secure and encrypted on their storage space too. But I what I haven't seen advertised is giving the user an option of encrypting the data with the user's own passphrase, at the client side, so that the service provider cannot have access to the data. Well, without a quantum computer, that is.

I know I could keep my data encrypted by using an encryption software like TrueCrypt, and then back up the encrypted data storage - but I really don't want the hassle of keeping all the data on my home computer constantly encrypted. I also expect there would be some hassle from the backup process. And the whole reason for using an online backup is not having to deal with all the hassle.

Are there online backup services that:

1. Encrypt all data with my passphrase before it gets sent to the server
2. Use strong cryptography for the encryption
3. Do not store or transfer my passphrase anywhere (or keep it stored strictly client-side)

I do realize if I lose my passphrase, the backup becomes useless. This is not a problem, since I'm not going to forget my passphrase. Or if I do, tough luck for me. :)

I also realize that since I'd be most likely using a proprietary software, all it takes from the software provider is an update that makes the software send my passphrase to them. The only true way to ensure privacy would be to use a known open-source software. However, I'm not worried about this risk. (By that thinking, my data is already compromized by any proprietary software I run, regardless of whether it's backup related software or not.)

The software would be mainly for Windows use, but linux support is a nice addition.

Since there are some inane restrictions for cryptographic algorithms in some parts of the world, I'll also mention that I need the service in Europe.

Similar, but not identical, topics:

• Online backup for personal use
• How to keep your privacy when using an online backup service?
• Best choice for a personal “online backup” in Europe

Answer 1

SpiderOak is probably your best best. They have a zero-knowledge policy and I think they cover most of your three points. I have a review on my website if you want to take a look. Another benefit is they are cross platform. Windows, Mac and Linux and offer sync as well so you can install it on more than one machine and sync files between them. The benefits of Dropbox and Backup for the same price.

Answer 2

Cloudberry Backup will do that for you.

• Encrypts with a unique key before transferring to the cloud.
• They have versions for S3, Google Drive, Azure, Rackspace.
• The company has a great Windows freeware client for S3 file transfer, as well.

Answer 3

I would suggest looking at Wuala.

Wuala is secure storage for all your files.

Wuala is secure cloud storage, a haven in the cloud to store your files. You can safely access and share your files with friends, family, and co-workers.

Answer 4

I like that CrashPlan allows you to backup to a drive, take that drive to another location (friends house, whatever), set it up on their computer, and then do differential backups to that drive. It really solves that “initial full backup is too big to go over the network” problem. That part of the service is free. So, bonus. And as mentioned, the backups will be encrypted so your off-site partner can't snoop through your files.

Answer 5

Mozy lets you choose your key also. It asks you to either enter your own key or let the server generate a key at installation time.

Answer 6

Have you looked at tarsnap? It's billed as "backup for the truly paranoid" :)

Answer 7

I also like crashplan.com

Here is a link to the (somewhat buried) documentation about using a private encryption key.

I'd have added this link as a comment but I don't (yet) have the rep...

Answer 8

Backblaze does this and talks about encryption here

Answer 9

Jungle Disk

(Oh well, I guess I should do some in depth research before asking a question. I have no idea how I missed this one.)

Jungle Disk uses AES-256 encryption, which gives you enterprise- level protection for your data. Since you create and control the security key, you truly control the data.

Jungle Disk is the only online storage service where the application is de-coupled from the storage and you "own" your own data. You can choose a custom AES-256 encryption key so that all of your data is encrypted before it leaves your computer, and stays encrypted while stored.

Jungle Disk uses a unique key for each file, and constructs the key using a HMAC file that helps protect against certain attacks. The master key is based on a password YOU choose, known only to you and not stored with Jungle Disk.

OS support: Windows, Mac, Linux.

Payment model: Price depends on how much space you use, no other limits.

... so, any others?

Answer 10

Carbonite encrypts all of your data, and you can choose the key if you wish or you can let them choose it. I've been using them for several years and have been quite happy with it.

Here's a page on their help section that explains a little bit about their encryption.