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How do you check that your printer isn't secretly storing your key somewhere? I've looked for open source/open hardware printers some time ago, unsuccessfully.
by Tharre 9y ago
How do you check that your printer isn't secretly storing your key somewhere? I've looked for open source/open hardware printers some time ago, unsuccessfully. I've written my main key down on paper by hand as a backup, but it's a tedious task.
As you mentioned fire-resistance, do you also use some sort of fire resistant paper? Because I don't think anything in made of paper would survive an actual fire.
- dom0 9y ago> I've looked for open source/open hardware printers some time ago You want a pen plotter. Or its cheaper, more expensive cousin, the Axidraw. > As you mentioned fire-resistance, do you also use some sort of fire resistant paper? Because I don't think anything in made of paper would survive an actual fire. Actually there are document safes with built-in insulation which will keep regular paper documents safe for time X under fire conditions Y (it's some EU standard classification). Certain ways of mounting safes makes them intrinsically fire-safe(r) as well.
- graedus 9y ago> cheaper, more expensive Huh. It's cheaper (worse quality) but costs more money?
- cuckcuckspruce 9y agoI took it as cheaper to purchase, more expensive to operate.
- xelxebar 9y agoI was confused too, so looked up the prices. The pen plotter seems to be in the neighborhood of $225 USD [1] while the AxiDraw is $475 USD [2]. [1] https://www.amazon.com/pen-plotter/s?ie=UTF8&page=1&rh=i%3Aaps%2Ck%3Apen%20plotter https://www.amazon.com/pen-plotter/s?ie=UTF8&page=1&rh=i%3Aa... [2] https://shop.evilmadscientist.com/productsmenu/846 https://shop.evilmadscientist.com/productsmenu/846
- dom0 9y agoVintage pen plotters (or X-Y recorders) are essentially zero-price items and tend to be built like actual tanks. The ones you can buy today (and afford) are way more expensive than them, yet cheaper (in quality). However, vintage pen plotters tend to not have USB plugs.
- unkown-unknowns 9y agoSpeaking of plotters, consider engraving the QR code in aluminum instead of having it on paper. If there's any hacker space nearby where you live they might have CNC equipment that they will let you borrow and instruct you how to use.
- deleted 9y ago[deleted]
- digikata 9y agoEncrypt before sending it to QR code?
- brandmeyer 9y agoThe GPG private key should be password-protected. Its basically symmetric encryption keyed off of the password using something akin to scrypt.
- digikata 9y agoOh, then a printer secretly storing that representation of the key doens't matter, correct?
- Grollicus 9y agoOf course, because that drastically reduces the key space. Before: 2^2048, After: 256^20 = 2^160 (when using a 20 key password. Obviously you could use looong random generated passphrases, but then you could just base64encode your key?)
- palunon 9y ago2^160 is still a massive key space for symetric encryption. Symetric and asymmetric encryption don't have the same key length standards.
- Fire-Dragon-DoL 9y agoCan't you buy a 50 printer, print it and destroy it after that?
- oh_sigh 9y agoWhat's the point of encrypting it? It seems like just another thing to mess up, and much more likely that you'll forget the password versus someone breaks into your house, goes into your safe, and knows what a private key is.
- zokier 9y ago> I've written my main key down on paper by hand as a backup, but it's a tedious task. Elliptic curves are nice because they allow short keys, for example curve25519 uses 32 byte keys that are pretty reasonable to copy manually (44 base64 chars or 64 hexs).
- im3w1l 9y agoFor RSA keys shouldn't it be possible to store some 256 bit seed and then use a deterministic algorithm to convert that to a 4096 bit key?
- icebraining 9y agoEven if there is, such a key would be much less safe (assuming the attacker knew the algorithm, which must be assumed, otherwise why keep the key in a safe?)
- ecesena 9y agoPrime number generation is typically done like this. Pick a random number, then add 2 until you get a prime. So you can do something similar. Pick a deterministically generated bit string, and use as key the next prime number (you need to do it twice, for p and q). You certainly get less security and I unfortunately don't have any reference to quantify that. As I was saying in another post, I'm writing about deterministic password generation (i.e. not RSA keys). Draft here: https://medium.com/@0x0ece/how-i-manage-my-passwords-technical-version-8549dc1bde1e https://medium.com/@0x0ece/how-i-manage-my-passwords-technic...
- jopsen 9y agoAlso the keys can be any random secret... Meaning you could use PBKDF2 of your favorite passphrase as your private key, then keep it in organic memory. Personally, I would love to see a strategy for generating a private from an analog picture.. But I don't see a good way to do it reliably.. Maybe one could generate it from error correction bits in a QR code.
- zokier 9y ago
- sigjuice 9y agoEngrave it on stone or etch it on metal or both :)
- nosuchthing 9y agoM-DISC's are archival grade DVDs/Blurays, and when properly stored M-DISC DVD recordings are claimed to last 1000 years. https://en.wikipedia.org/wiki/M-disc https://en.wikipedia.org/wiki/M-disc
- sigjuice 9y agoI think I have more faith in the people who built the Pyramids than those peddling these fancy optical discs :)