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Ask Slashdot: How To Keep Keyfiles Secure, But Still Accessible?
New submitter castionsosa writes: With various utilities like borgbackup, NetBackup, zbackup, and others, one uses a keyfile on the client as the way to encrypt and decrypt data. Similar with PGP, GnuPG, and other OpenPGP utilities for the private keys. However, there is a balance between security (keeping the keyfile in as few places as possible) and recoverability (keeping many copies of it). Go too far one way, and one will be unable to restore after a disaster. Go far the other way, and the encryption can wind up compromised.
I have looked at a few methods. PaperBack (which allows one to print a binary file, then scan it) gives mixed results, and if there is any non-trivial misalignment, it won't retrieve. Printing a uuencoded version out is doable, but there would be issues for scanning, or worse retyping. There is obviously media storage (USB flash drive, CD-ROM), but flash isn't an archival grade medium, and optical drives are getting rarer as time goes on. Of course, stashing a keyfile in the cloud isn't a wise idea, because once one loses physical control of the medium the file is stored on, one can't be sure where it can end up, and encrypting it just means another key (be it a passphrase or another keyfile) is stored somewhere else. I settled upon having a physical folder in a few locations which contains a USB flash drive, CD-R, and a printed copy, but I'm sure there is a better way to do this.
Has anyone else run into this, either for personal recoverability of encrypted data, or for a company? Any suggestions for striking a balance between being able to access keyfiles after disasters of various sizes (ransomware, fire, tornado, hurricane) while keeping them out of the wrong hands?
I have looked at a few methods. PaperBack (which allows one to print a binary file, then scan it) gives mixed results, and if there is any non-trivial misalignment, it won't retrieve. Printing a uuencoded version out is doable, but there would be issues for scanning, or worse retyping. There is obviously media storage (USB flash drive, CD-ROM), but flash isn't an archival grade medium, and optical drives are getting rarer as time goes on. Of course, stashing a keyfile in the cloud isn't a wise idea, because once one loses physical control of the medium the file is stored on, one can't be sure where it can end up, and encrypting it just means another key (be it a passphrase or another keyfile) is stored somewhere else. I settled upon having a physical folder in a few locations which contains a USB flash drive, CD-R, and a printed copy, but I'm sure there is a better way to do this.
Has anyone else run into this, either for personal recoverability of encrypted data, or for a company? Any suggestions for striking a balance between being able to access keyfiles after disasters of various sizes (ransomware, fire, tornado, hurricane) while keeping them out of the wrong hands?
Saying this isn't any better than saying "if you've done nothing wrong, you've got nothing to hide."
You use encryption to protect your privacy from a US government that no longer understands what the 4th amendment is.
As for backups, you can backup your private key with a password and throw it on a couple USB drives stored in different locations. I've printed out my encrypted RSA key. Elliptic curve keys are small enough that you can usually print them out with QR codes (even after encrypted).
Failing figuring out how to encrypt your key for every random program, I would just throw them all in veracrypt, and then again, few different USB drives, ideally not stored in the same place. Check on them every six months or a year or so.
Key files, certs, etc. are all convoluted versions of the same thing - a secret.
Your question is really: "How do I keep my secrets secure?"
The answer is, as always: "Memorize them."
If your secrets are too complex or too numerous to memorize, you will need to write them down.
Because you're not an idiot, you write them down encrypted, and memorize that key so you can decrypt it later. This key is your secret.
If you're doing it correctly, you won't care where you store the encrypted secrets, because the security requirement is effectively binary. If you have security set to "on" because you used strong encryption, then you can turn accessibility to over 9000.
Throw your password database on a public FTP and let the world have it. You'll be long dead before the encryption is cracked.
If you're paranoid and you think usable quantum computers are really 5-10 years away, or that every encryption algorithm is flawed and backdoored, then you need to rely on hiding as well to turn security on. Put your shit on a micro SD card and hide it. Or, hide your shit by embedding it into innocuous data (digital or physical) steganographically. Or both. Or you could roll your own crypto on top of an established crypto.
In my organization, we've switched over to using Yubikeys for handling our private key storage. Our primary use case is SSH keys for remote terminals and git repositories, but there is no reason why it couldn't be used for other secure encryption methods too.