VANITY: Question for anybody who has moved Bitcoin to cold storage

June 16, 2024 | E. Pluribus Unum

[E. Pluribus Unum]

I would like to move some Bitcoin to cold storage, but the thought of doing it wrong and losing it forever scares the Obama out of me.

If you have done it, how did you do it, how do you store the wallet, and what is the possibility of messing it up and losing it forever?

[E. Pluribus Unum]

I plan on putting it in cold storage and “hodling” it indefinitely.

What you said in the first part is probably exactly what I wanted to know.

I will have to study what you sent me. I may ask you a few more questions over the next couple of days.

I do not want to mess it up, obviously.

[Drago]

OK....I have been into Bitcoin since 2012 or so...so can probably help. 😉

If coming from CoinBase or similar it will be a bit more “tricky”....before you can record your “seed phrase” on steel you will need to have a seed phrase and I don’t think CoinBase or other exchanges provide the private key to the end user. (Thus the phrase “....not your keys,, not your crypto”).

[palmer]

I went to coinbase and typed my password, their website sent a code to my phone to let me in. I tried to "send" from my bitcoin stash and it said it wanted my ID. So I sent it a front and back scan of my DL which I had on my computer. Now it will let me send to an address.

Then I cloned this git repo: https://github.com/pointbiz/bitaddress.org and looked at the code. Sure enough it still has complete self-contained javascript for generating random numbers, create ECC keys, displaying the QR codes, etc. So I ran it in another browser by opening the bitaddress.org.html file stored on my computer. I moved the mouse around for entropy for the random number and it generated a private key and corresponding address. I printed it.

Next I scanned the printed private (they call it secret) key into the mycellium app on my phone. I honestly don''t know what app to trust anymore, and mycellium seems to be a little junked up with promotional stuff. But you won't need to do that until you want to spend. I did it simply so I know (1) the private ("secret") key on the paper is readable and (2) my proceeds will actually be transacted from coinbase to my brand new address.

Next I copied the address (derived from public key) from my other browser into the coinbase screen where it asks where to send the bitcoin. I set the amount I wanted to send. Next coinbase texted another code to my phone. I typed that code into the browser. Then it said "sent".

Next I opened mycelliium on my phone. I see the amount that I sent from coinbase on my phone. Had to wait a few minutes, long enough to type the message to you above. I now have my private key in two place: on a piece of paper about to go in my safe, and in my phone.

Bad policy someone might point out. Almost everyone generates private keys (with corresponding address) from seed phrases and they transact the bitcoin to the generated address. They always generate a new key/address for every transaction. But I don't care because right now I am cold storing like you. I happen to have a second copy of the private key on my phone at this moment. But I could erase that any time I feel like it. Or spend it. I haven't decided. I don't know when I'll decide. Either way there's the paper in my safe with the same private key.

[E. Pluribus Unum]

Thanks for the step-by-step.

I need to study it for a few days make sure I don’t mess up.

[palmer]

Just to be clear: in step 2, generating and printing a paper wallet with a private key, I am trusting code from the internet. It's been there 8 years untouched unless Github is lying about that. Or it's possible it was compromised prior to 8 years ago and has remained compromised.

What does that mean? Two basic possibilities: the private key that it generates is not secure. It might just pretend to generate a random number after collecting entropy when it might simply be choosing the next number in a pseudorandom sequence (looks random but isn't) that the bad guys can predict.

Second possibility the javascript has hidden code in it to send the generated private key to the bad guys. I could preclude that by running the javascript on a second computer that's not online. Or taking my computer offline, running, clearing browser caches, rebooting, then going back online. But I am much too lazy to do all that.

I think the bitaddress.org code is probably secure enough for my purposes. Drago please feel free to correct if you disagree.

[palmer]

Try those steps with a small amount first. If you decide to install mycellium app (which I can't vouch for but use nonetheless), then you can verify that small amount really went from coinbase's stash (which they own but pretend some of which is yours) and got transacted to your brand new address.

Furthermore you will know that the private key was readable by the mycellium app and you can spend at some point in the future.

There's a detail I left out in using the mycellium app. You have to click on add key icon like usual. But then you must scroll down to advanced and use "Scan". The warning right above that say that there is no backup. But that piece of paper in front of you, about to be put in your safe, is your backup. So if it all works, then you know your backup works.

But be sure to use "Advanced and more" and click scan to copy the private key from the paper into your mycellium app. Do not "sweep". Some apps only "sweep". If you sweep then the proceeds are transacted from that private key to a new private key and the paper backup now has a balance of zero.

[Drago]

Yeah...study always helps before “jumping in”, basically like FReeper Palmer said above, you can derive your private key from CoinBase, but you DON’T want to use that CoinBase private key to transfer the funds to an “intermediary” wallet before you record your seed words in steel. CoinBase could use that key to drain your Bitcoin later if they wanted to...you need a new private key and TRANSFER/SEND your Bitcoin to the new fresh/unadulterated by an exchange BTC wallet address/private key. So: from exchange/CoinBase-—>send BTC-—>to new never used BTC wallet/private key-—>record seed words from the new trusted/fresh wallet-—>stamp seed words/phrase into steel-—>delete “intermediary wallet”-—>put seed words/phrase in a safe place.

[palmer]

Here are three screen shots if you decide to use Mycellium. Drago please chime in if Mycellium is not appropriate.

Click on the "key+" symbol. Scroll to the bottom of the next screen and click on "Advanced & More". Click on "Scan" right below the warning. Aim the phone camera at the "secret"key (not the address). After it snaps the QR you will be asked to label that key (i just use the date which is their default label). Next you will see another (or your first) entry in the listing that I blotted out in the top screen shot. The important part is it will have a key icon in the left column meaning it knows the private key.

[palmer]

I agree in principle with the seed phrase generation technique. I don't think it is necessary for cold storage if you have a trustworthy way to generate a private key directly (not from a seed phrase).

There are advantages to seed phrases and using a hardware wallet and most apps you have no choice. However Mycellium allows an exception, you can simply scan a private key and t will store it in phone memory (encrypted and as secure as the seed phrase).

If you think Mycellium is not good for any reason, please let us know.

[Drago]

Hi, I personally haven’t used Mycellium....(I have used “Exodus” and “Atomic” wallets in the past for smaller amounts of BTC)...and I hear that the “Trust Wallet” is good. I personally have the bulk of my BTC in a Ledger HW wallet, and am looking to transition it to a ColdCard HW wallet (best “air-gapped” wallet IMHO).

I don’t trust any smartphone wallet for a large amount of BTC (at least have an encrypted copy of your private key OFF of the smartphone).

As for “seed phrase” vs “private key” they are essentially the same thing...the seed phrase makes it easier to save your private key vs. worrying about how to write down a 256 bit HEX #:

“In Bitcoin, a private key is a 256-bit number, which can be represented one of several ways. Here is a private key in hexadecimal - 256 bits in hexadecimal is 32 bytes, or 64 characters in the range 0-9 or A-F.

“E9873D79C6D87DC0FB6A5778633389”.

https://en.bitcoin.it/wiki/Private_key

(Easier/more understandable for humans to record the 24-word phrase):

https://www.ledger.com/academy/private-key-and-seed-phrase-whats-the-difference

[palmer]

I don’t trust any smartphone wallet for a large amount of BTC (at least have an encrypted copy of your private key OFF of the smartphone).

Agree in part. The smartphone wallet will lose private keys. It will lose the seed phrase. Personal experience with both. Or you will lose the smartphone or factory reset it or delete the app or ... However I keep my unencrypted private keys in my safe. Don't need to be encrypted.

As for “seed phrase” vs “private key” they are essentially the same thing...the seed phrase makes it easier to save your private key vs. worrying about how to write down a 256 bit HEX #:

Yes, they are the same, but seed phrases are better because they generate an endless supply of keys. But for cold storage that doesn't matter. However you do not need to write down a 256 bit hex number. I have created dozens of private keys , given some away (to people who trust me). Many in my safe. Never written down a single hex number. That's because the paper wallet generates a QR code and you send that to the printer. Maybe you don't trust the printer and that's a fair point. But I am not dealing with a million dollar stash.

Here's a private key I just generated on bitaddress.org Do not use this key

The address on the left is the address which you cut and paste into the "send to" field at coinbase. The "secret" key (private key) on the right goes in the safe after sending it to the printer (which you trust). There's no writing down hex numbers and making a mistake. The QR on the right can be scanned into mycellium wallet with the instructions above.

Thanks Drago for your feedback especially if I have overlooked something. I have created many private keys like this for as much as 1 bitcoin without problems.

[chud]

I happen to have a second copy of the private key on my phone at this moment.

I've always heard that you shouldn't keep a private key on your phone...

[palmer]

To sum up the steps I would do if I were not a geek. Use a browser that you don't use much (e.g. install Firefox if you haven't already). Use that browser to go to bitaddress.org Since you can't really trust anyone disconnect from the internet at this point.

The client-side code will continue to work. Keep moving the mouse to get enough entropy to generate the private key. When it is done the client side software will produce the SHARE and SECRET shown above. Still not on the internet (and thus not connected to your printer) save a screenshot of the browser as I did and shared above. You should be able to right click in Firefox and select "Take screenshot". Then copy that to the clipboard. Bring up MS Word and paste into a fresh document. Next, copy and paste the SHARE address that starts with 1b into a document. That's a public address so no security is required.

Close the bitaddress.org browser tab. Clear the cookies and data. As it turns out Firefox has no cookies or data for bitaddress.org and it should not. If it did, that would be a security flaw. But clear cookies and cache anyway.

Now you can connect back to the internet so you can get to your printer which is presumably on your home network. If you have an old fashioned printer connected to the computer that's even better since you won't be on the internet. But in either case print the word document with the SHARE and SECRET shown above.

Next you can load mycellium to test the private key import. That way you know your paper wallet is readable. Follow the steps above. I will test other wallets Drago mentioned to see if they can import private keys. If you successfully import the private key you can see a key on the screen that I screenshotted above (the one that is partially obscured so you can't see my pathetic holdings)

Next log into coinbase. Send them your DL scans so you will be allowed to send to an address. Click on my assets so you can see what you got. Click on Transfer in the top right. Copy and paste the SHARE address that you saved above into the "send to" field. You may need to click on the arrow in send to to get a field to paste in the address. Once the address is pasted you can preview the transaction. Then do the transaction. I just did it and used the key above that I said to not use. It's up to someone reading this thread to scan in the private key I pasted above and claim the $8 in bitcoin. It will be good practice. Good luck

[palmer]

It turns out I accidentally sent the $8 to the address I created last night. So I just sent $8 from that address to the new address in the thread above. So next I will import the private key into my phone by scanning it. Note that the private key is on the image sharing server (which anyone can access), it's on this thread which anyone can read and scan it in and it will be on my phone soon. Anyone can claim the $8, they just need to the first to transact it to an address of their own or to an online site that sells cheap candy bars and takes bitcoin.

[palmer]

That's correct. A private key on a phone is vulnerable to someone who hacks the phone. Furthermore as Drago pointed out the private key can simply disappear or you can drop the phone in the lake. But my private key on my phone is a duplicate of the private key on the paper wallet in my safe. So I don't have to worry about the loss scenario, just the theft scenario.

[palmer]

Here's screenshot of the $8 stash associated with the address and private key that I revealed in the thread:

You too can claim the $8 in value by loading the mycellium app, and scanning the SECRET QR code. Since that private key is public to the world, someone may have already spent the money. But if not you should see what I show above.

I sent that bitcoin from my coinbase account to the SHARE address using the instructions that I typed in the thread. That worked. If the private key were not public I could print the SECRET and put the paper in my safe. I would still check that the paper is readable since I just imported from the screen, not paper. But it should be readable.

In summary, there are two problems with bitcoin: loss and theft. I posted a private key which will be "stolen" as I intended. But it's your job to make sure that never happens with your private key. Print the private key, put it in your safe and make sure there's no trace of the screenshot left on your computer by clearing cache, closing the browser. I'm pretty sure bitaddress.org is safe to use, but doing the key generation off the internet should ensure that.

To avoid loss you print the private key and make sure your printout is readable by importing into Mycellium. I know that private key is readable from my computer screen and it should also be readable if I printed a screenshot.

[palmer]

Tried exodus and atomic as mentioned by Drago. Those both create keys from seed phrases. They don't allow importing a separate private key outside of the pass phrase generated keys.

I created a wallet with atomic and wrote down the 11 words that make up the pass phrase. Next I scanned my fingerprint for ease of use. It also, separately, accepts a password to unlock the wallet. I went to BTC, I clicked on receive. It generated an address for me to receive some bitcoin. I could copy and paste that address into the coinbase form where it asks for an address.

In theory the wallet on my phone should be secure (not leaking the pass phrase). In theory it should be safe from loss, I should be able to install the same app on another phone, type in the 11 words and get all my keys back. I can print the 11 words and put the paper in my safe.

It's considered more secure than private keys. But is it really? Private keys can be leaked or stolen, but so can the 11 word pass phrase (in theory). It is considered more secure for transactions and I agree. Reusing the same address for multiple is considered a weakness and that's what happens when you store a private key. I do private keys mostly and am not too concerned.

Is is safer from loss? No, a private key in a paper wallet in your safe is as safe from loss as a paper with the 11 words printed on it.

[GunRunner]

That the entirety of earth will be without electricity?

This is the newest talking point from Bitcoin critics. Every single other prediction they’ve made has been proven wrong, so they’ve resorted to FUD about global blackouts that last forever.

It’s best to just ignore these people.

They are a denial of service attack on your time.

[aMorePerfectUnion]

Agree 💯

[Drago]

Thanks for the additional info...”self-custody” is a bit more complicated than leaving your BTC with an exchange/Coinbase!
My primary concern with your “import private key” methods is that you don’t want to have your private key known by Coinbase (theft...Coinbase generated your private key & could use it for nefarious purposes if they wanted...I have “trust issues” ;-)). Also your old Coinbase transactions can be easily “trackable” by the government or others with the old private key/public key transaction addresses. A fresh private key from a new wallet prevents this...generate a new wallet then send/transfer your BTC to the new unadulterated wallet/private key. (And DO NOT reuse public key transaction addresses from your new wallet for maximum privacy...one use per address). If really paranoid then use a “whirlpool/bit-mixer” to obfuscate/privatize the BTC that came from Coinbase:

https://bitcoinmagazine.com/guides/how-to-whirlpool-bitcoin-on-mobile

https://coincheckup.com/blog/bitcoin-mixer/

If you want to help support the BTC network (you are an official “node” of the BTC network) and “mine” BTC you can use the original/first/”OG” Bitcoin “Core” software to make your new/fresh BTC private key/wallet...(it will download the whole Bitcoin blockchain ledger of BTC transactions back to 2009 tho...takes a long time unless you have a real fast Internet connection...currently 578 GB!)

https://bitcoincore.org/en/about/

https://bitcoincore.org/en/download/

Your odds of mining a BTC “Block” by yourself with BTC “Core” (you get over 3 BTC) is exceedingly low tho...best to go with a BTC mining “pool”:

https://cointelegraph.com/news/bitcoin-halving-2024-completion-confirmed

https://www.hedgewithcrypto.com/best-bitcoin-mining-pools/

https://99bitcoins.com/bitcoin-mining/pools/