Paper Wallet security versus Printer memory

LoyceV

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Quote from: truthstalker on October 20, 2017, 02:43:11 AM

Just don't use a printer if you are skeptical of it. Use A Live linux cd and dot down the private key on a piece of paper.

Reading and typing a printed private key is already likely to result in a mistake, writing it down and having to read your own handwriting (many years later) only increases the chance of mistakes.
There is of course software to recover a partially lost private key, I stumbled upon it once, and saved it for if I ever need it: in a few minutes I can brute-force up to 5 lost characters from a private key.

A better solution is using a very cheap (laser)printer, cheap printers can't store anything. If you're totally paranoid, you can always destroy it when you're done, new toners cost as much as a new cheap printer anyway.

truthstalker

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Just don't use a printer if you are skeptical of it. Use A Live linux cd and dot down the private key on a piece of paper.

Flanagan

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Quote from: aplistir on October 19, 2017, 09:23:32 AM

How about using a paper wallet with an encrypted private key?

Then it wouldn't matter if someone copied your paper wallet. Because you can't spend from it without the additional key.

bittaddress.org can make those.

From According to Do All Printers Have a Hard Drive? site mentioned:

"Security Considerations
When your business decommissions a leased or purchased output device, its hard drive can form a security risk because of the prospect of sensitive data remaining on disk...."

So we should all worry about this !
*
Re Paper wallet with an encrypted private key will look at this.
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Re Tails Live CD...don't see how that can protect one from a printer's hard drive storing what you print....

LoyceV

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Quote from: Flanagan on October 19, 2017, 06:38:39 AM

I will follow the advice about printing some garbage and clearing the spooler

That seems like a waste of toner. If you're using a Linux LIVE CD (offline!), everything runs from RAM. Turning off your computer is enough to lose everything on your LIVE session, and turning off your printer does the same on the printer.

Quote

I thought that some modern printers actually had a sort of hard disk inside that stores many images of scans or prints, even if you clear the PC printing spooler ?

According to Do All Printers Have a Hard Drive? it's much more common than I thought, I expected only the very big printers (like this one) to have internal storage capacity.
If a printer stores the last prints, I would assume a printer can re-print the last page even after it has been turned off. My printer even starts processing data from the computer again when it has to print the same page a few times, so I'm pretty sure it doesn't store anything.

aplistir

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How about using a paper wallet with an encrypted private key?

Then it wouldn't matter if someone copied your paper wallet. Because you can't spend from it without the additional key.

bittaddress.org can make those.

WildWestRider

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It's amazing the things you start to think about when you get into cryptocurrency and how to keep it safe! Something else to think about now...

Flanagan

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Thanks for all the replies / help.
No, it's not about having a lot of BTC. Actually it's only to make a paper wallet for a non computer savvy friend who wants to buy a small amount to start and I want to put it in a paper wallet for extra security for him.
I will follow the advice about printing some garbage and clearing the spooler, but I thought that some modern printers actually had a sort of hard disk inside that stores many images of scans or prints, even if you clear the PC printing spooler ?
Of course, always using Linux for anything related to btc.
No time to purchase the HW wallet as he wants to buy soon. Will get one for myself though, thanks.

nexus2k14

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Quote from: Flanagan on October 18, 2017, 08:25:22 AM

Hi,
If I print a paper wallet with one of the available offline applications to do so, since most printers nowadays have an internal memory, isn-t this a security risk if that same printer is again used in the same Pc ?
How does one erase a printes memory for good ?

Clear printer memory with CMD. Disconnect your computer from network, no LAN/WiFi, print using your software paper wallet then clear printer internal memory from Command Prompt (CMD)
1. Open CMD from start menu by typing "cmd" or Win+R / cmd
2. Type: net stop spooler
3. Printer spooler momory should be clear now.
4. Power Off/On printer

You can also use more secure environment like TAILS, boot OS from USB/CD and use Linux software to manage Bitcoins.

clip123

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If you are paranoid then you can may be get a hardware wallet? assuming you have large amount.

mocacinno

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I always just reboot the printer after i've printed paper wallets... It's memory, it should be cleared when the printer is turned off.

But NeuroticFish is right, if you're really paranoid, you can fill up the printer's memory with a useless pdf, just to be sure... Or you can put the printer on top of a big pile of wood in your garden and burn it Wink

NeuroticFish

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Quote from: Flanagan on October 18, 2017, 08:25:22 AM

Hi,
If I print a paper wallet with one of the available offline applications to do so, since most printers nowadays have an internal memory, isn-t this a security risk if that same printer is again used in the same Pc ?
How does one erase a printes memory for good ?

I think that you are overthinking it.
I've never heard of malware getting data from your printer memory. And why? The only reason to do that would be if the hacker knows that you have large amount of Bitcoin. And then it's cheaper to hire some big bad boys to handle this and you'll hand over the private keys, no need to read printer memory.
Also, if you have such big amounts of Bitcoin, I think that hardware wallet could be a better option than paper wallet.

And as direct answer to your question: print some other worthless data on the same printer before going online, the new data should overwrite the memory.

Flanagan

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Hi,
If I print a paper wallet with one of the available offline applications to do so, since most printers nowadays have an internal memory, isn-t this a security risk if that same printer is again used in the same Pc ?
How does one erase a printes memory for good ?

Topic: Paper Wallet security versus Printer memory (Read 384 times)