Bitcoin Forum

How many of you keep your cold storage in multisig addresses for additional security?

I've been doing this bitcoin thing for a little while now and I've built up a decent stash. I have mine on a standard address I created with dice, and backed it up on thumb drives, paper and in a safety deposit box at the bank. My back ups are still in base 6 format so if someone else somehow came across them they likely wouldn't know what it was or how to convert it -- so I think it's pretty secure.

Wondering how many of you keep your stash on multisig addresses.

I am using standard address so far, but I am thinking to move it to multisig. How the others? I am looking for ideas.

I use both. Cold storage with multi sig wallet. Not that I have something to protect, unfortunately, but still, I like to play safe.

I've been wondering the same thing.

I keep my stash on various paper wallets. But I'd have to figure out how to make a multi-sig wallet if I was going to move them.

Is it possible to create multisig paper wallet ? If yes, how ?

I suggest you to use a multi address, or better use greenAddress the web wallet with a lot of features. Check it here:

- https://bitcointalk.org/index.php?topic=521988.0


However in that case you have asked for a cold storage so it should be "offline" then in that case the type of address does not matter (so much).

Yea you can create one manually with bitcoin core in the console, and then save the 3 private keys, and the redeem script to paper. Easy for a typo error though, so I'd probably use a USB thumb drive instead of paper.

...

I have enough BTC to want to protect them, but not large enough to really worry about it.

My solution is to keep most of them split between a Ledger Nano and a Trezor (hardware) put away in cold storage.  And enough (small amount) at blockchain.info for convenience.

But, I do hide the Ledger and Trezor!  I just read on another thread that the current Trezor can be defeated with a skilled user of an oscilloscope.

I know nothing about multi-sig.  Someone could write a useful post (I hope) that would introduce the subject to us non-tekkies.

I only use paper wallets as cold storage lot safer than using anything else and only take them out when really needed to.

I don't have that much though, but still a pretty decent amount to protect. I'm using a standard wallet and printed it in a paper, laminated it and keep it in a place where I think it's safe. I don't want to complicate simple things for me but if events push me to do so, then I'll probably look into making one.


Reading the thread now, and it seems that I wouldn't jump on this green address yet until I fully understand the concept of multisig addresses. Thanks for linking this one, redsn0w.

I have a good chunk of my coins in Cold storage, and don't really sway towards going over to have multi sig for them.
Cold storage is usually pretty safe.

I was keeping my bitcoins in standard wallet with good strong encrypted password. What is multi Signature and how can I use it ? Where I can get it from ? How is it more safer than standrad encrypted wallet ?

I currently don't use multisig. The few Bitcoins I have are on paper wallets and on cold storage devices.

When I started saving Bitcoins on cold storage I was still pretty new to all this and saved them on a paper wallet. Later I discovered Armory and I've been using it since.

I've been thinking a lot about multisig in the last few months, but I don't think they would add much more security to the setup I already have. I can either have a split paper backup in many places or the private keys and redeem script to use a multisig address in many places, so there isn't much of a difference. Armory has lockboxes, but I haven't really tried them, as I see no need to use them...

Either there is no advantage in a multisig address on top of cold storage saving, or I'm missing something :) If one can physically obtain a split backup, they can also obtain everything they need to spend from a multisig address.

I only see multisig as an advantage on cold storage saving when it comes to having a shared address, just like a shared bank account... Maybe it's really useful in those cases.

Think of it like adding an additional lock to your front door.
Standard address only needs one key to get inside.
Multisig addresses can require M of N keys to get inside. (i.e. 2 of 3, or 3 of 5, 4 of 20, whatever/etc).

Here's a good written tutorial:http://sx.dyne.org/multisig.html

D'Angelo goes over them with his blackboard series:  https://www.youtube.com/watch?v=zIbUSaZBJgU
There's also this guy:  https://www.youtube.com/watch?v=ZKRLJGBMqWo

I keep my coins on Electrum, which is not a multisig wallet. I understand the advantages of a multisig. Then I would have to keep 3 "things" really safe instead of just 1. I might have to do that someday, when I have a huge amount, not worried about it now.

That's partially why I'm asking, if I should go multisig.
I was thinking, if someone broke in and found my private keys to a standard address they could figure out how to use them pretty easily, even if they weren't advanced with bitcoin.  If someone broke and got my multisig keys and the redeemScript they would have to know how to execute a raw transaction in bitcoin core in order to steal them, so there is that additional level of security that it requires more technical knowledge to use.

Now I understand. Instead of "breaking" only 1 "lock", the attacker should "break multiple locks" in order to gain full control of my wallet. Well that seems to be a pretty good thing if you have a large stash that needs some hiding. But I think I'll still use the paper wallet one for now. Anyways, thanks for the links and the information.

Multi signature is good option for those who can not store their Bitcoins in cold storage as paper wallet is safe but same time is very risky to take care good care of that paper. I think it is more better mix your Bitcoins by using some mixer service and keep them in your wallet which to be installed in some device which has less contact with internet.

Not ahd to take care of it. Simply laminating it and sealing up so water and air tight and the need something to unseal is what I do and job done never let me down yet. Why would you want to mix your coins unless want true anonymity with them so no trace but still waste time to mix coins if spending or using in later months to come or for other reason I could understand but odd to mix without reason.

Well I am new to the Cryptocurrency world...so I don't fully understand the meaning behind Coldstorage. Have read that word a lot in many different threads...just never got the guts to ask...What exactly is cold storage?

Cold storage is in other words an offline storage, it can be for instance a paper wallet or an encrypted wallet.dat stored on a USB stick. When you have a wallet that you're using daily to process transactions it's your hot wallet.


Same here. Maybe if I had a small fortune in Bitcoin I'd be more inclined to make paper wallets and stuff. When I had more coins I used a dedicated netbook running ubuntu that I turned on only to process the payments. Now I don't even bother and keep most stuff online, just divided between different wallets.

Just make sure them sites are not going to go anywhere had that with 4 or more exchanges with online wallets. Lucky didn't have much in them and ran into problems going off line hacked and other news on them and come back and now waiting on re payments from the exchange that seems to not be budging much. Like you Panda I use online wallets to some level but too many sites now pop up and come and go just be careful with them :)

https://imgs.xkcd.com/comics/security.png


A multisig address will protect your from the "$5 wrench" attack.  If you use a 2 of 3 multisig address you keep one yourself, give one to you mom and then put a third in a safety deposit box.

That way if you die your mom can get the safety deposit box and access your coins, you can still access your coins without your mom by going to your safety deposit box or you can just send a transaction to you mom for approval (because, yeah, you mom always needs to approve your spending anyway :P ).

When bitcoin reach $10K per coin, I might consider more secure measures, now offline storage is enough  ;D

The real problem for me is that I want to spread the risk by using multiple addresses, then it is a pain to maintain several wallets at different locations, and I might forget about one of the encryption password If I don't repeat them every week :D

10k per bitcoin ill fall of me chair if it ever got to that and 10x the bubble what went pop when gox went and then pop again and again. Will need some serious investments and people hauling and buying up to reach that with some serious demands for btc to ever get to that stage

I know it's silly, but it always amazes me that with all the crazy technical algorithmic cryptographic hot/cold wallet innovations, the most secure might be paper. ;D

Me

Great comic! LOL ;D But wouldn't they simply get your 1 of 3 multisig address, ask you who has the other multisig addresses, then visit your mom and give her the same "$5 wrench" attack? The multisig address idea endangers your mom, too.

In other words, only use the multisig technology if you hate your mom.

Regards,
Me

Feel free to use your wife instead :P .

Right after I use smart contract technology to take out the $1M life insurance policy. ;D

(Please don't tell her I said that.)

Me

It makes the most sense to save your backup unencrypted in a safe deposit box. If you die, you'll want your heirs to have access to your bitcoin.

If you're worried about the authorities or others getting access to your safe deposit box without your authorization, then you have bigger problems, and the multi-sig option among your cohorts is probably a better solution.

i'm still using the conventional 1 sig address and a usb for cold storage, i don't see the need to move them to a multisig address to be honest, as long as they are off-line encrypted wallet they are safe

I always keep telling people that multisig doesn't actually 'increase' the security of their coins or make the key more complex or whatever. But being protected against the $5 wrench attack makes so much sense, actually.... Thanks for that input!

Whats a good way to cold storage the coins that isn't via a hardware wallet? Is the method of going to bitaddress.org, downloading the HTML and creating the wallet with the internet turned off a safe way to do this?

The bolded part is good and safe. Use both mouse and keyboard. When Mycelium Entropy is released, you can give it a try.

P.S. @OP: I recommend multisig address.

I recommend either multi-sig or Shamir's Secret Sharing where some of the keys are encrypted and digitized and some are secured physically in cold storage. Mixing physical and digital security will dramatically raise the costs of the attacker and only make you vulnerable to multi- million dollar , multi year efforts like Ulbrict and even he didn't secure his coins properly.  

Using a clean install of linux/ubuntu with armory wallet  on a spare computer and taking the right security precautions is one way to accomplish this.

Another is using mycelium entropy with Shamir's Secret Sharing.

Additionally, it is a good idea to split your BTC between multiple sets of sharded wallets so you don't have to import your whole life savings if you want to dip into your savings.  

Here is more info - https://bitcointalk.org/index.php?topic=858604


Yes, this is sufficient for most people with small balances .. people who own more bitcoin should take extra security steps,.

I think cold storage is more safe than multisig. All you should do is keep your private key away from online.

What do you think if the coold storage will be created with a multi signature address 2of3? This could increase the security and I am 100% sure ;).

If you create it in an offline computer, it will be better. You should make sure a backup is made and nothing is exposed to a third person other who you trust.

I've never used a multisig wallet, not even sure what that is.
Does it mean you can create an address, give your address to get paid but once you get paid it automatically creates new addresses? (does this make sense? if that is not multisig then I want to know how to do what I just said).

From the three private keys, how do I create one bitcoin address ? Does bitcoin core support this feature ?

Not exactly, I suggest you to read here :

- https://en.bitcoin.it/wiki/Address#Multi-signature_addresses


TL;dr :
Addresses can be created that require a combination of multiple private keys. Since these take advantage of newer features, they begin with the newer prefix of 3 instead of the older 1. These can be thought of as the equivalent of writing a check to two parties - "pay to the order of somebody AND somebody else" - where both parties must endorse the check in order to receive the funds.

The actual requirement (number of private keys needed, their corresponding public keys, etc.) that must be satisfied to spend the funds is decided in advance by the person generating this type of address, and once an address is created, the requirement cannot be changed without generating a new address.

---

Here https://coinb.in/multisig/ you can 'play' a little bit with the creation of multiSig addresses.

For many more comics like that, see xkcd.com (https://xkcd.com/538/).

The question is, is it worth the extra hassle?

In my opinion it's not, but that's just me. Nobody is Bitcoin knowledgeable around here... Even if they were, it's not easy to physically get what's required to spend my cold storage coins. Summing up, I think a mix of physical protection and minimum security measures in storing private keys digitally that makes cold storage good. Don't get me wrong, multisig is amazing, but for folks like us, storing funds just for ourselves, I don't really see a big need in multisig :)

What is the "dice" you refer?

I hope it is not a dice site.

A dice site? Like gambling?  :D Oh no way.
I mean dice like real physical dice.

https://i.imgur.com/wefBH8v.jpg

Yes, you can do it in bitcoin core console.
All you need is the 3 public keys in hex format (i.e. 0347f3394ff0a223332b1de34d51c4cd5cd381d390c890b82fbd00af059f22e19d).

And do the command:  createmultisig 2 '["pub_key","pub_key2","pbk_key3"]'

Example to make a 2 of 3 multisig wallet.

Also, don't send any money to a multisig address unless you are comfortable with sending raw transactions.

If you want to secure your bitcoins get a trezor,but you don't need a multisig,because that does not provide more security to your bitcoins if you are the only owner

I simply create multiple copies of BIP38 bitcoinpaperwallet.com paper wallets. Put a good password on it, print up copies of the same one and put them everywhere.
Download the source and do it all offline.

No, I do not think this is a right decision to move multisig. I think cold storage is more safer than multisig.

What do you mean comfortable with sending raw transactions?
Doesn't a multisig address accept coins sent using the normal way?

In Bitcoin core, you need to manually create a raw transaction and sign it. He is talking about it. Newbies can use different client which is multisig-friendly. For example, Armory.

OK, thanks.
I didn't know about that.
So far I am only using Bitcoin Core with standard addresses but I was considering multisig addresses.
i guess I will try Armory then as I don't like too complicated things  ;)