Topic: Is this method secure for cold storage? (Read 1167 times)

I am not so worried about the creation of the cold storage, than I am worried when you sweep that bitcoins from cold storage to some online wallet. The hackers have used several methods to hijack these actions to get to those bitcoins. Make sure when you copy and paste Bitcoin addresses, because they have Malware that replace your Bitcoin address with their Bitcoin address.

I have swapped to hardware wallets for every day use, and I am not using online Apps or online wallets anymore. It is just too risky. ^hmmmm^

Since you can use different addresses, you can distribute your money along may Bitcoin addresses. If your wallet is "broken" you can at least keep the money on other addresses.

It's like a boat, you can have two or more divisions inside the hull, so a single hole can't sink you.

Of course this isn't a security measure, this is only a small barrier.

Also the best way to wipe that freespace is filling it with random data and then deleting it again, that can be done multiple times (although one is already enough to almost every situation that isn't theorical ).

It does and you probably read the remark on gmaxwell here about in browser software -> https://bitcointalksearch.org/topic/m.10995631


Password managers are great, but they are also a single point of failure. If the file is gone and the password is known all your passwords are known. That does not mean you shouldnt use one. It just means you should be aware of the risks and e.g. keep it locked most of the time.


Thats a good point. I dont see a particular problem with using bitaddress.org to generate addresses even though I agree with most of the points Blazr made in the other thread.


I dont own a hardware wallet, but from what I can tell they are pretty secure against several types of attacks.


I will probably hang around in #bitcoin[1].

[1] https://en.bitcoin.it/wiki/IRC_channels

your problem is in your step 1:


if you disconnect from internet you don't suddenly turn into cold storage, secure mode.
as a rule of thumb if your computer was connected to the internet even once before you should consider it Not Safe.

the reason why live linux is suggested is that a live linux that you are running for the first time is considered secure since it has not been connected and also linux has less security holes like windows and you can "assume" there is no viruses for linux.

here is what you should do instead.
1) download bitaddress.org
2) verify its signature so you know you have downloaded the right thing.
3) transfer it to your live linux which has never been connected to internet and never will
4) generate keys there and save them by writing them down or if you are using one of those wallets with seed like electrum write down the seed
5) remove the live linux and you are done, everything is also wiped from your computer if it was a live linux without persistence.

Shorena > see what I mean.....sigh. SMH. The never ending rabbit hole of security. Effin' hackers. This is good. It's a never ending race between the good guys and the bad guys. The thing that pisses me off the most, we both know 80% of these hackers could spend a LOT less resources to just hack our freakin' regular banking accounts.......but they're not in it for the money per se. They're in for the puzzle and the lulz.

https://bitcointalksearch.org/topic/time-to-bust-a-myth-paper-wallets-are-less-secure-than-normal-encrypted-wallets-1013586

Shorena , thanks again. I'm not completely unfamiliar with encryption and security as I have used Truecrypt in the past.

I've been down this rabbit hole before, but for different reasons. Well, no, I guess it's ultimately for the same reason > the protection of MY data.

I understand the live CD idea, although I think it's a pain in the butt. But I will do it because it's absolutely needed. (even though I don't have SSD) I still agree it's necessary.

I'm just not sure I'm ready to go down this rabbit hole again when it involves money. I mean, there's so many ?'s that I NEED to understand. 1st question would be to question the bitaddress.org generation process. (the math behind it, not the actual mechanical moves I need to click) I know it's generally trusted and accepted and let's be real, that makes it a target.

So, you mentioned encrypting my private key. Yes, I totally agree. I currently use a fairly popular pw manager that generates random pw's for you. I have it set to use 32 characters, Upper -lower, #'s and special characters and even obscure words if it wants. THE TRUTH IS > I DON'T EVEN KNOW MY PASSWORDS... That's the truth. But so far I've only changed my pw's to this format for such things as facebook, email, social media stuff, forums like this, nothing really critical.

But I'm thinking if I implement the live CD part, the bitaddress.org part with BIP38 and a random generated PW that is say....100 characters in length, I'm thinking I'd be pretty damn secure. Light years ahead of most noobs at the least.

I'm not a mathematician though. So I can't calculate out how long it would take to brute force something like that. I imagine it would take longer than the universe has been around. But I'm pretty confident I'm on the right track with security. What is your take on Trezor? My take is that if it's man made, it WILL fail. Period. Just a matter of time..... for example, can a Trezor withstand incredibly strong magnets? What about an EMP pulse? Or, am I missing the point entirely because they can all be "restored" from a seed? (?) I'd like to be able to chat with you real time if possible....I'll leave that up to you as to how and even if you would be willing to do that. Because even with your input HERE, I am by no means even remotely close to being comfortable enough to say, > YES, I'M SURE I know what I'm doing. How am I supposed to get others involved with btc when I can't even explain the security aspect of it in a mathematical way. "Just trust it" - doesn't cut it with me, and it's not going to cut it with others either.

To the other fella / gal that mentioned deleted files aren't really deleted, (essentially), I agree. Can't speak for Shorena but I'd be flabbergasted if he/she didn't already know that as well but MANY people are not even aware of that fact. So, thank you for bringing it up. Perhaps it will help others in the future.

Free space isn't always empty space. When you delete a file, you're really just deleting a reference to where it's stored.

Kinda, yes. The critical part is to make sure you completly remove the data before you go back online. Thus it would be better (I think someone suggested this upthread) to use a live linux system. You can download and verify the download even on a compromised system or -even better- use a DVD/CD (not USB) created on a clean system. Tails is great for that as it was designed under the premise to leave no trace on the system its booted on.


That sounds very secure in terms of desaster as well as hackers as long as they know how to handle private keys (e.g. dont upload them to dropbox or google drive). You could do one better and use encrypted private keys. Bitaddress.org has a mode for this. The password can be simple or the key can be in a sealed envelope. The parents might have a safe where you can store it?


See above, use a live linux. I just stumbled over the word I guess. Data can be increasingly problematic to remove from a disk. Mechnical disks are fine once the data is overwritten several times. SSDs not so, they do not allow direct access to the sectors to reduce wear. The best approach here is to avoid data written to disk in the first place. The simplest solution for this is a live OS that does not automatically mounts the hard drives.


Yes. An alternative that might work slightly better, just because its easiert to write down, would be to generate an electrum seed instead of a single private key. IIRC Tails even comes with an electrum version, but I would still download and verify the latest (currently 2.7.12) one. This would give you words to secure and they are less likely to write and read wrong. I dont think its too much a of difference though, because Im sure you will be extra careful when writing it down.

Shorena...... Thank you so much for your very detailed answer. Let me clarify something please. When I said at the very start "Assuming my PC isn't infected...." The rest of what I wrote would seem to = true. It's actually quite the opposite, as you stated. I DON'T assume my PC is clean. I MUST assume it is compromised already (which I do), despite the various virus scans, malware scans etc that I do routinely that always come up "clean."

Clean or not, when it comes to my money or btc, I STILL must assume it's compromised. What I was implying was mathematical really. If PC / (any operating system able to generate the keys) = Clean...then the rest of what I wrote would seem to = true, if I read your response correctly.

You asked about what my security concerns / threats were. Mine are strictly hackers, glitches in "the system", etc..... I do not keep my btc on exchanges etc for this very reason. I am not worried about family members, home intruders, etc. As for my private key, I believe 3 to 4 copies should suffice. My brother would get a copy. My best friend would get a copy, and my wife and I would have a copy and perhaps her parents would have a copy. (you gotta trust somebody) They are all spread out all over the country.

As for "wiping" the free space, I'm not going to insult your intelligence. You know there are programs out there that claim to do just that, but I get the feeling you have some sort of issue with this from a security standpoint or you wouldn't have brought it up. So...??

It sounds to me like what I've concluded is correct, now I just need to figure out how to generate a clean, uncomprimizable key pair ---- which I absolutely DO NOT TRUST my PC to do. That seems to me to be the bottom line in my whole security "plan." *IF* I can get a secure key pair, the rest of my plan should be ok. Right? If not, please tell me where the holes are so I can re-think it. Thanks again.

You can never be sure. This only works if the attacker does not suspect this or does no (or slow, e.g. weekly) automated checks. How long to wait till its safe? How large an amount to test in order to bait a possible attacker? If nothing happens for 2, 3, 42 weeks, does that mean you have not been compromised? No, it does not.

Thats also not the point. The point of establishing a secure concept is to make up an attacker you want to defend against first. OP didnt not do this, thus "is this safe?" can always be answered "no" with some attacker in mind that OP does or does not cares about. E.g. in my first reply here a family member or a guest.

To be sure of that, put some BTC on that address. If they will get stolen, it was compromised, if it will not be stolen, u can safely use it for your permanent cold storage.

Yes it seems a secure way. Better yet, you can use a linux system to handle the job. I am not saying it is risk free but there are much less spyware/malware/trojan created for linux systems. So your chances of getting robbed are much less.

Is that a realistic assumption? What attacker do you have in mind when this is not the threat you want to attack defend against?


You dont need backups of the address(es). You can literaly tatoo it on your forehead and its no security risk.


Why all these steps if your first assumption is that your machine is clean? How do you "wipe" free space on your hard drive?


Its offline and thus "cold", yes.


Its a privacy issue not a security one, if you are the only person sending coins there and you dont give the address to different people it should reveal no information about you and the amount of coins you hold.


However they "break" the wallet, they cant get the private key from the address held offline.


I cant answer this question without knowing against who and/or what you want to protect yourself. If you are concerned about someone in your family this would be terribly insecure as they could just grab your paper wallet. You also just said you want to store the private key "in different places", but no information about these places? Could they all be affected by the same fire? Could they all be affected by the same large scale (flood affecting your city or similar) catastrophe? What exactly are you worried about? If you can answer all of the above questions for yourself, you should be fine. If not, think about them. Security is never 100%, so make sure you know about the percentage(s) your setup does not(!) protect against.

Edit: typos

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Why do you think so?


Why do you suggest linux if OP explicitly said they dont worry about spyware etc. Plus the number of viruses of a specific OS matters little, a single one is enough to shatter your security setup. Linux and MacOS has malware as well, its not magically immune just because there is less of it.

Assuming my PC isn't infected with any spyware, etc......

1) I get the bitaddress.org file downloaded to my PC. I disconnect from the internet and generate a paper wallet.
I copy and paste my public address into notepad, or whatever. I make backups of that address and store in different places.

2) Regarding the private key, I'm still offline, I simply write down on paper the private key and make copies of it too and store accordingly (IE: > it never gets used in the online world until I'm ready to move the bitcoin.)

Once I have my both address and key stored, I would shut down bitaddress.org.....clear all my history, etc from my browser, then "wipe" the free space on my hard drive. Then I'd reconnect to the internet. The Private key has never been seen by anyone but me.

3) I use Mycelium wallet (or any wallet really) to send bitcoin to this new public address.
As long as I keep my private key safe, isn't this effectively 'cold storage?' And is this correct? (all of the above)

I do have one question though....which is still bothering me. I would be sending bitcoin this public address on a weekly basis from Mycelium wallet. But I've also read you shouldn't reuse addresses or send to the same address over and over again.

I assume at some point, hackers are going to figure out how to break Mycelium. And I'm fine losing $100 or so from the wallet....and yes, they would in theory then see all this money I've sent to the public address....but if the private key has never seen the light of day in any digital form....I don't see how they could break into that address.

I would strictly be using this new address to "stash" or build a "nest egg" of BTC. ---- Do I have the security correct, or not? Please advise. Thanks.