Bitcoin Forum

I've searched the forums, and the variations of this question are not often specific enough to get a solid answer, so here's my situation and question;

If I have an older MacBook that I no longer use but that works great, and I have it reset to factory specs, then install a wallet on it, and use that computer as a "cold" wallet, with all wifi and wireless settings turned off, and only physically plug the laptop in when going online (20 minutes here and there) and unplugging it... could that be considered safe enough to be a secure place to store BTC or other crypto?

A MacBook and it's settings is something I'm familiar with, have an extra, and like being able to put different kinds of wallets on it.

I'm not talking about connecting to wifi now and then, I'm talking about ONLY plugging in the ethernet cable when going into the wallet and unplugging it when I'm finished.   If I have the spare laptop (can't sell it, it has sentimental value but I have a newer, faster one I use daily) would the experienced on here say that's a secure way to store coins?

I would consider it safe enough, but it's not the ideal cold storage setup as soon as you connect to the internet even once.

If all you do after formatting your laptop is install the wallet and transact from time to time, without never opening any website or downloading any software, it's way more secure than just storing your coins in your everyday laptop/PC.

That is not an offline computer.

One option is to use Electrum. Put wallet on this offline Macbook (that is ALWAYS offline) and watch-only wallet on normal computer, then sign transactions with a transaction file through USB stick. See docs for better explanation: http://docs.electrum.org/en/latest/coldstorage.html One could argue putting USB in offline Macbook is still a risk, but IMO a smaller risk than your solution for an "offline wallet".


edit: of course your solution is still more secure than average wallet out there.

I would say that is secure enough. If you are not going to use it for browsing the internet or anything else online you should be safe. But it will also depend on the type of wallets you are planning to install and use on your MacBook. Make sure those are legit and downloaded from a safe location. How were you planning to get the wallets to your device? I would advice against connecting USB devices on your Macbook to prevent any possibilities of infecting it via the USB, just in case.
And of course make sure you have your private keys/seed/wallet.dat stored at a safe place.

It is not safe, because you use it online.
If you can't use only offline, and you don't have an other option, I would run TAILS.
It runs on MAC too and it has Electrum installed.

You were good up until this point...


And then ruined it here... :-\

By connecting it to any network for any period of time, this should no longer be considered a "cold" wallet.


Most likely, assuming other precautions are taken... it will be "OK" from a security point of view... but by connecting this laptop to the network, you are effectively removing ALL of the safety barriers that a true cold wallet provides.


Given that it would take a piece of malware mere milliseconds to send your wallet.dat and keylogged password to a thief, it makes no difference how long it is connected for... if you want to properly implement the cold wallet setup, the laptop should NEVER be connected to any network after it has been setup.

You should run the "online" watching-only wallet (with just public keys) on your daily computer... then the process would be:

- create unsigned transactions on online wallet (it has updated wallet balance/transactions)
- transfer unsigned transaction to offline wallet using a USB stick
- sign transaction on offline computer with private keys
- transfer signed transaction back to online wallet using USB stick
- broadcast signed transaction

At no point, should your offline laptop be connected to a network if you want to consider it a proper cold wallet.

You can't call that an "offline" wallet, but you can make it a secure laptop. Then I'd say, sure; because you can remove OSX and put Linux on it :)

A true offline wallet is something like a piece of paper with your seed words (privatekey) written by hand, and your addresses so you know where to send funds to. By using any online blockchain explorer you can simply verify any transactions done to it.

The day you want to move funds out of it... It becomes "online" because you are installing the wallet software "somewhere" and activating it. This should, ideally be done with a live iso, because YOU WANT everything to disappear afterwards.

So the short answer to your question is: No, you can't.

And yes, believe it or not it is possible to boot USB sticks or optical media from "macs", which is all you need to boot something decent like Linux where you should perform any offline wallet creation, or manipulation.

Even if OSX can better than windows, its by no means secure. Besides Apple loves to drop support to older models, you are better getting rid of it sooner than later when your updates stop coming...

I have a dedicated laptop for crypto fun. The first thing I did was take out the wifi card and bin it. With the possibility of going online gone completely it's much more relaxing fiddling with seeds, QR codes and more.

No way would I ever feel 100% comfortable using it in that capacity if there was any possibility of it hitting the internet again.

There are wallets that can sign transactions offline and broadcast with an online counterpart - http://docs.electrum.org/en/latest/coldstorage.html

I have a solid answer for you.

How could that go wrong:

1.- The hard drive dies, this way you could lose the BTC
2.- Someone gets physical access to your mac and dump the PrivateKeys.
3.- You get hacked. (In some of those short 20min access to the web.)


In the end, there is no 100% secure way to hold btc, but i will recommend you to take a look to paper wallets. You can use programs like VanityGen to create an addy and private key, then put that info in a text file and the file inside zip with a password. That way your bitcoins are secured by a password. Or at least get a physical wallet like Ledger if you want to feel more secure.

A BIP38 encrypted paper wallet is much easier and safer than using a zip file.