Can I get my Crashplan encryption key with just my passphrase

I have a Crashplan account that I chose to encrypt. Like Carbonite and BackBlaze, I entered an encryption passphrase during setup and my backup was off and running.

It's now a month later and my hard drive just died completely. I tried to log into Crashplan to restore my files but it's asking for my encryption key. I entered my passphrase but that did not work. I wrote to support, but they just said that there's a difference between the key and passphrase and did not explain further. With my past backup providers I just used the passphrase for restore, so I'm confused and very worried that Crashplan has expected me to write down the unmemorizable key somewhere.

Being that the key was derived from my passphrase in the first place, how can I recreate the key given that I know my passphrase? I no longer have Crashplan on my computer as it was installed to the hard drive that died.

crashplan

Nicholas

Posted 2014-08-17T01:36:46.660

Reputation: 179

1Without the key we can't help you. – Ramhound – 2014-08-17T01:54:02.373

@Arjan Sorry. I will elaborate. – Nicholas – 2014-08-26T12:06:36.240

Answers

I did not find a way to recreate my key from my passphrase, but instead found a workaround since I still had access to my system drive. There is a file at:

 C:\ProgramData\CrashPlan\.identity

This is a plain text file that can be opened in notepad. Within is your encryption key which can be used to unlock your Crashplan backup.

I also eventually received an email from Crashplan support. They told me that in the case of a total drive failure I could reinstall Crashplan and go through the same steps I did last time to generate my key. This key should then be the same as my previous one, and usable to unlock my backup.

Nicholas

Posted 2014-08-17T01:36:46.660

Reputation: 179

Wow, that is good news! – Arjan – 2014-08-26T16:56:45.267

@Arjan Yes. Though keep in mind that since I had already retrieved my key I never tested CP's suggestion. – Nicholas – 2014-08-26T17:42:47.310

Unfortunately, the only way to restore files from the archive, if you've chosen the Custom Key option in CrashPlan, is to have the key. The company does not have the ability to bypass the security.

If, on the other hand, you selected the Archive Key Password security level, they might be able to help you.

Here's a technote on the CrashPlan site with all the details - ARCHIVE ENCRYPTION KEY SECURITY

Mike Evangelist

Posted 2014-08-17T01:36:46.660

Reputation: 21

Thank you. I guess what I'm trying to understand is if the key was created by running my passphrase through some algorithm, why can't I run my passphrase through that algorith again to get the key? – Nicholas – 2014-08-17T16:50:32.033

@Nicholas, "if the key was created by running my passphrase through some algorithm", why do you think it was created that way? Couldn't it be some random key instead, which was then protected using your passphrase? (I'm not using CrashPlan, I have no idea.) – Arjan – 2014-08-17T20:09:04.720

And, @Nicholas, do you recall if you selected some extra security options during set up? – Arjan – 2014-08-17T20:12:53.640

@Arjan Thank you for the response. I don't believe I did choose any additional options beyond encryption via a passphrase. It was not clear at all that the passphrase wouldn't be enough. I question Crashplan's decision to even include this option, given a key would need to be written down, thus seriously undermining the security benefit. – Nicholas – 2014-08-18T12:34:30.390

Again, @Nicholas, I don't know CrashPlan. But common sense dictates that anyone who allows a user to select some security option that might make that user lose their data, would show big fat warnings to said user. And as I assume you would remember seeing such warning, I'd say that it's actually very likely that you're NOT using any special security at all. So, it's likely that the passphrase should simply suffice, and I suggest asking their customer support again. Maybe even point them to this very question. Did the link that Mike gave help you? – Arjan – 2014-08-18T17:14:29.820

Mike, just in case you're interested and missed the edit: see Nicholas' answer. – Arjan – 2014-08-26T17:00:13.783