4 ms·

Backblaze: to decrypt your backup, send us your private key passphrase

13 points by noja 11y ago

jonathonf 11y ago
Firstly, the submission title is not a quote (for anyone wondering). Secondly, how else do you expect the process to work? They don't hold your key, so to decrypt the data you have to provide the key. The data is held on their server, and to decrypt it to send to you they have to decrypt it. So you have to provide the encryption key at some point? Once you have your data restored, you can change the encryption key.
- ianlevesque 11y ago
  An obvious alternative would be to decrypt the backup locally instead of entering the key into their website.
- noja 11y ago
  You decrypt locally.
- dogma1138 11y ago
  Locally or even during download in the browser mega.nz sends you encrypted blobs which are decrypted using the download auth key after the download is verified they use html5 storage and JavaScript to achieve this.
- jdenning 11y ago
  >Once you have your data restored, you can change the encryption key. Unfortunately, even if you change it, they still have access to the files encrypted with the previous key. Also, it's generally recommended to test the restoration of your backups, otherwise you can find yourself in a really bad spot if/when you need to restore - IMHO, this definitely includes verifying that there wasn't an error in the encryption/decryption process (i.e. changing the key would necessitate testing decryption with the new key, which requires giving them the new key).
- jonathonf 11y ago
  Thank you all for prodding my brain in the right direction. :)
jdenning 11y ago
>So to recap: if you never actually prepare a restore, we cannot possibly know what is in your files, but if you prepare a restore (let's say of a few files) then for the couple minutes they are being prepared and downloaded they are in "plain text" on a HIGHLY SECURE system in the Backblaze datacenter. LOL - so you get to choose between having a backup that you can't verify by doing a test restore, or encryption that isn't secure by putting your private key on an un-trusted/non-audited server that you don't control. > Backblaze focuses on ease of use. It is backup for people who need backup and "pretty good security" and who aren't computer professionals. At least they acknowledge that "computer professionals" would likely be skeptical of these options; on the other hand, it seems like they are downplaying the lack of security in this scheme to their non-"computer professionals" clients: >All your files are encrypted before being transmitted over SSL and stored encrypted. [1] EDIT: >... even a malicious hacker in our datacenter could not possibly compromise your data.. [2] That's just false, and I'd bet they know it. I mean, they only use their root keys on an air-gapped (non-networked) host, right? If not, then they should really consider hiring someone who understands security a little better. Want to convince me your system is really "HIGHLY SECURE"? How about guaranteeing $1,000,000 payout to the user in the event of a breach? I mean it "could not possibly" happen, right? :D [1] https://www.backblaze.com/cloud-backup.html https://www.backblaze.com/cloud-backup.html [2] (from the article) https://help.backblaze.com/entries/20926247-Security-Question-Round-up- https://help.backblaze.com/entries/20926247-Security-Questio...

13 points by noja 11y ago

Firstly, the submission title is not a quote (for anyone wondering). Secondly, how else do you expect the process to work? They don't hold your key, so to decrypt the data you have to provide the key. The data is held on their server, and to decrypt it to send to you they have to decrypt it. So you have to provide the encryption key at some point? Once you have your data restored, you can change the encryption key.

ianlevesque 11y ago
An obvious alternative would be to decrypt the backup locally instead of entering the key into their website.
noja 11y ago
You decrypt locally.
dogma1138 11y ago
Locally or even during download in the browser mega.nz sends you encrypted blobs which are decrypted using the download auth key after the download is verified they use html5 storage and JavaScript to achieve this.
jdenning 11y ago
>Once you have your data restored, you can change the encryption key. Unfortunately, even if you change it, they still have access to the files encrypted with the previous key. Also, it's generally recommended to test the restoration of your backups, otherwise you can find yourself in a really bad spot if/when you need to restore - IMHO, this definitely includes verifying that there wasn't an error in the encryption/decryption process (i.e. changing the key would necessitate testing decryption with the new key, which requires giving them the new key).
jonathonf 11y ago
Thank you all for prodding my brain in the right direction. :)

jdenning 11y ago

>So to recap: if you never actually prepare a restore, we cannot possibly know what is in your files, but if you prepare a restore (let's say of a few files) then for the couple minutes they are being prepared and downloaded they are in "plain text" on a HIGHLY SECURE system in the Backblaze datacenter. LOL - so you get to choose between having a backup that you can't verify by doing a test restore, or encryption that isn't secure by putting your private key on an un-trusted/non-audited server that you don't control. > Backblaze focuses on ease of use. It is backup for people who need backup and "pretty good security" and who aren't computer professionals. At least they acknowledge that "computer professionals" would likely be skeptical of these options; on the other hand, it seems like they are downplaying the lack of security in this scheme to their non-"computer professionals" clients: >All your files are encrypted before being transmitted over SSL and stored encrypted. [1] EDIT: >... even a malicious hacker in our datacenter could not possibly compromise your data.. [2] That's just false, and I'd bet they know it. I mean, they only use their root keys on an air-gapped (non-networked) host, right? If not, then they should really consider hiring someone who understands security a little better. Want to convince me your system is really "HIGHLY SECURE"? How about guaranteeing $1,000,000 payout to the user in the event of a breach? I mean it "could not possibly" happen, right? :D [1] https://www.backblaze.com/cloud-backup.html https://www.backblaze.com/cloud-backup.html [2] (from the article) https://help.backblaze.com/entries/20926247-Security-Question-Round-up- https://help.backblaze.com/entries/20926247-Security-Questio...