Bitcoin Forum

I've been reading about  Deep Cold Storages on wikipedia here: https://en.bitcoin.it/wiki/Cold_storage

It seems to be way more secure than an ordinary Cold Storage as my private key and everything would be stored in a safety deposit box which you must have to be able sending funds out from the wallet. So basically, without that box you can do nothing to the coins being inside my wallet.

I'm looking forward for the safest solution(money doesn't matter) as I need to store serious money safely there.

Thanks for your help...

I think the safest is a non-desktop, non-mobile solution. All you need is a private key. I recommend looking into multisignature which would require more than one key to send bitcoins on the network. You could get a 2-of-3 wallets, which means you need at least two keys out of the three keys generated.

I'd recommend generating different paper wallets and store different amounts of BTC little bit everywhere , make sure to encrypt the private keys and don't forget the passwords .
But since you said that the money doesn't matter then Case wallet (a hardware wallet) should be good for you : https://choosecase.com/ and it's also considered as the world's most secure and easy-to-use bitcoin wallet

Their website says it's sold out...  I cannot get one.

What's now ?

Out of the methods listed, hardware wallets seems most secure to me. The only problem with paper wallets (and I using them as well) is when you actually want to spend it you have to find a secure way to do it (with higher amount of Bitcoins)... so probably importing the private key to hardware wallet anyway  :)

http://www.bitcointrezor.com/ is probably a better fit for your needs than case.

Then try to get a Trezor which should cost only 99$ and it also compatible with most of the Desktop wallets out there like Electrum and Multibit HD so you won't find any difficulties on using it .
If you want real reviews from people who actually use it (there is plenty), then I'd suggest going to "Service Discussion" section and asking about Trezor wallet .

Klestin,

Why do you think that Trezor is more secure than ChooseCase ? Please explain!

did you read what you posted?

A simple example of deep cold storage is opening a safe deposit box and putting a USB stick containing an encrypted wallet file in it. The public (sending) addresses can be used any time to send additional bitcoins to the wallet, but spending the bitcoins would require physical access to the box (in addition to knowledge of the encryption password).

it only mean that for deep could storage is expected another layer of additional security, like in the case of usb you put it in a safe box and memorize the security number instead of laying it around on a4 paper, so not even a real life thief could steal it

Okay, Amph

Then tell me please what should I do now.

Apple mac mini's are ideal to store huge amounts of bit coins.


Buy a  pair 2014 mac mini's

cost = 499 + 499  

install latest  bitcoin core on one of them.

then use cloning program super duper to clone a few copies to of the hdd


http://www.amazon.com/gp/product/B00APP6694?psc=1&redirect=true&ref_=od_aui_detailpages00


so you have 4 copies of the oem hdd and two mac minis.

put one mac mini with the bitcoin core in a safe deposit box.

keep the other mac mini in your home

keep 2 hdd clones each of the bitcoin core in 2 different bank safe deposit boxes.

So you have 4 clones and an oem hdd  on one mac miniof the bitcoin core all in safety depost boxes along with a mac mini at home with no bitcoin core on it.

When you need money go take a clone put it in the dock and use the in home mac mini to boot and use it to withdraw coins.

Purchase a physical wallet and make many backups

Thanks for the detailed reply, philipma1957 but I wish to keep things offline..

Which physical wallet/storage do you think to be the most secure ?

What exactly do you want to protect against?

Are viruses your only concern? If so, a simple, old, offline laptop with electrum 2 is enough.

Are you also concerned about fires or other distasters that might destroy the laptop? If so, you could create encrypted backups of the seed for the offline wallet. Store them via something like shamir's shared secret scheme to only need n out of m parts. That way you can put the backups into several places, e.g. 1 with family, 1 with a very close friend, 1 with a safe deposit box, 2 in secret locations in the woods/mountains only you know about.

i believe the best thing to do would be to create an offline paper wallet and deposit the funds there and hide the wallet somewhere safe at least thats what i did with my bitcoins

i don't like paper wallet, and the printer may put at risk their alleged security, and they ar enot that easy to use, i prefer usb pen drive, but many of them

then you can either put them underground in a container, at least 1 meter, or the safe box like the wiki say, but i don't like it too much, because usually thieves search for it, underground seems better if you have a garden or soemthing

paper wallet rewrited on stanless steel sheet with a DREMEL.

---

But, personaly, i use a bitcoin core (on a dedicated refurbished PC with cleaned OS) with wallet.dat stored on 20 differents supports of storage.
My life economies are on Bitcoin network since 2014.

Like this, i only import wallet.dat and can emit transaction in 1 minute if needed.

Thanks a lot for your answers!!

I'm concerned about being robbed by thieves/hackers or even by the company who sells a physical wallet for me.
I'm not concerned about disasters as I can have an offline laptop safe easily.. though I will make some encrypted back ups of the wallet.

Yeah..I don't like paper wallets, really hard to deal with them.

Amph:

What physical wallet to go with ? Which is the safest ?

too complicate for me.

other wallet : android bitcoin wallet for android on a "clean" nexus phone (that it doesn't contain other tool than the ordinary android OS).

problem = battery after a couple of years.

That requires internet connection so that you'll most likely to be hacked sooner or later.

First of all deposit your bitcoins to an online wallet or offline wallet .
Backup your entire wallet , not only one address or two make a backup of entire wallet.
Use a complicated password and save it somewhere so you don't forget it .
Keep backing up your wallet . Make backup online to your email but email is not safe too . Make a backup in your Stick.
Use offline wallet they are popular as cold storage they provides the highest level of security for savings. It involves storing a wallet in a secured place that is not connected to the network. When done properly, it can offer a very good protection against computer vulnerabilities.

This is completely silly.  It shows you don't understand security at all.  With this, all you've done is reduce the remarkable security of a private key down to a stupid physical hunk of metal key (the unsafe deposit box).  Obviously, you think a deposit box is high security - when in fact it is very low security.  Now you propose putting your key behind that terrible system.  Wow!  That is the same as taking your SLR and putting Toyota body panels all over it.  Not smart.

Isn't there a wallet which offers SMS-verification for each requested transaction before proceeding on top of the 2-FA and multisig signatures ?
It would be also a great thing if the wallet could send an email as well on top of this everything in order to proceed the requested transaction.

This seems pretty safe for me as in the case I get hacked, the hacker will have no access to my phone to receive the text message verification code!

Isn't there a wallet which offers sending me an SMS-verification for each requested transaction before proceeding it ? Obviously on top of the 2-FA and multi-signatures ?
It would also be a great thing to have an email sent to my email address as well with a confirmation link in it in order to confirm the transaction's genuine.

This seems pretty safe for me as in the case I get hacked, the hacker will have no access to my phone to receive the text message verification code! Maybe he can verify the email and everything else but not the Text-Message code that is being sent via an SMS to my phone!
So basically he can do nothing to my funds.

i'm using simple usb stick, sandisk, you don't need fancy usb to have your coin secured, the true security is the IQ of the owner not anything else

Yeah paper and hardware wallets better for High amount. In windows Electrum is good for saving and handling huge in a single or multiple wallet as well. Online wallets have a number of pros and cons I don’t recommend storing any bitcoins accessible on computers connected to the internet:)

Consider buying two Trezor bitcoin hardware wallets, one to use and one as a spare in case of loss. When you set up your Trezor you will be given a list of 24 words (order is important) called your seed. Trezor gives you a nice card to write your seed down on. Don't print it or save to your computer in any way. You will also be prompted to set up PIN protection. Unless you have a very good memory store the PIN and any passphrases in the safety deposit box also. Paper wallets are another option but bitcoin paper wallets are not safer than hardware wallets (https://bitcoinnewsmagazine.com/bitcoin-paper-wallets-are-not-safer-than-hardware-wallets/).

there are a lot of shops online that sell such things that are called hardware wallet it is the safest wallet that you can find in my opinion so the best idea would be to buy that wallet and then deposit all your bitcoins into it this way you could be sure that nothing bad will ever happen to your bitcoins

Even though hardware wallets are relatively safe i still cant see them being safer than a correctly created paper wallet and whats more is a paper wallet is many times cheaper than a hardware wallet. The only downside is its not quite as convenient when you want top spend some of those coins.

Try multiple addresses.  Depending on the amount of money / coins, I would say between 5 - 20.  That way, in the event that something happens to 1 key, you still have your coins.

I would say that the best way to hold a large amount of Bitcoin safely would to divide it up among multiple, multi signature wallets, and put them into offline storage, on something like a usb or an HDD, and then store it in one of the safest places you can think of. Whenever you want to bring it back out again, you can simply hook it up to a computer and then send the Bitcoins to wherever.

I would probably place most of my coins into multiple wallets if I had a large amount hidden away somewhere, but I don't have large amounts sitting around so I'm not sure what I would do.

I wouldn't really trust an offline USB wallet.  I've had too many usbs fail for no reason whatsoever.  If that's was to happen then day goodbye to your btc. A properly stored paper wallet / multiple paper wallets you can't go wrong.

If you don't like the paper wallet, there is a wallet that is also good like TREZOR me personally I haven't use it, but they are some good review with it and good experience. This good if you just want to hold or do other things with it.
But with online wallet with big amount of bitcoin just make more than just 1 online wallet.

Probably a physical wallet... Paper wallet or coins with private keys stamped on them.

for me the safest solution to store bitcoins is paper wallet as they have nothing to do with any electricity device and also internet so when they are not on internet they are safe from hackers but they can be stolen so keep them safe in your bank locker after laminating them

It is probably safe enough to use any desktop wallet and keep your computer malware free.

Guys!!!

Isn't there a wallet that sends SMS verification to my phone number before proceeding the requested transactions ?
As in this way nothing can happen to my coins as hackers have no access to my phone to confirm the numbers they've sent me in order to proceed the requested transaction(s).

A mixture of paper wallets, Trezor & Core is good enough for me.

An electronic medium is required to spend them. Most commonly used medium is a phone to send transactions. When generating a paper wallet, you need to ensure that the computer is safe and the RNG is not flawed. It would still be exposed to the internet and is hence quite an unsafe option.
That's basically 2FA, using a password and another OTP. Currently, there is no implementation in protocol level. You need to trust a third party to keep the funds safe. An example is coinbase.

But, there is another option. Multisignature addresses. Multi signature addresses basically needs at least n of m signatures for the transaction for it to valid. With 2 of 2 multisig, users have one key while a third party controls another. Only when the OTP is true, the transaction will be signed by the third party key.

With 2 of 3 multisig, the user have access to 2 keys while the server have access to one. Everything basically works like the above but the user can restore access even if the third party do not want to sign the TX. You would still have to keep the keys safe. An example is Electrum's 2FA option.

You think Electrum's 2FA is enough to keep safe ~200 bitcoins for me ?

Like you said earlier in the comments OP it's difficult for you to keep paper wallet,i am wondering how you keep your cash safely in real life? Think your paper wallet as large sum of cash and keep it in safe/bank or Just use an offline wallet and store it in PC that never gets connected to internet or any USB.These can be the only safest options i can think :)

Don't put all of those coins in the same address.  Use 4 or 8 addresses so that if 1 address is compromised, you don't lose all of your coins. 

Best option imho is to use "android bitcoin paper wallet" on totally offline phone. Just generate private key and write it BY HAND. Spending is bit cumbersome but possible offline and is not as weird as buying "two macbooks" for that.

then he will have to secure all of those 4 to 8 addresses so better store them in one address but secure is enough like i said for long long storage paper wallet will work as long as you use a good paper and ink and laminate it and secure it at safe place

Paper & offline wallets like Trezor are enough. For additional security you can maybe use Multisig as well.

Offline wallet is a very safe option...but make sure you have a licensed "internet security" software installed in your computer.

it's not about the method used, it's about the user, if you install electrum in a infected computer with a rootkit and heavy privilege access stolen by the hacker, nothing will be safe anymore

so simply pay attention to your moves


i can argue that a dedicated server on a separated connectiononly to run the client like it was your personal bank, can be safe as well

but what if hackers can see there are 200 bitcoins on my bitcoin address ?

they will do everything possible to steal it from me..

Than don't store your 200 bitcoins in one wallet always have more than one at least 2 so that 100 bitcoin in that other wallet. Always have a back up with your bitcoins. Do some bitcoins in paper wallet, some in offline wallet, some in a online wallet. Well good luck storing your bitcoins.

Yes what he said is true. It's best to spread the amount of bitcoins you have over several wallets if you own a bunch.
It's not safe to hold all of them in 1 wallet especially if you own bitcoins higher than 2 digits.

Even if a hacker knew that you have 200 btc in a bitcoin address, s/he can not do anything with bitcoin as long as your private keys are in a safe place and you generated this address offline.
Hacking an address by guessing its priv key will take billons of years

u sure?

it's a pain in the ass to deal with paper wallets.. so hard to spend money out from there

what if I purchase 3 pieces of Trezor and store the coins there ? is it safe ?

Just boot a Linux image on livecd and you can use bitaddress.org to do so.

You don't need to buy two macbooks to secure your Bitcoins effectively. If you have a old computer, you can install ubuntu with Electrum on it. You can use an online computer to download the transaction data, move it using a USB to your offline computer and sign it on the old computer. Then, bring it to broadcast on the online computer. If you don't have an old computer, a raspberry pi would do.

It will be wise decision to spread your bitcoin in different paper wallets and storing them in a different pendrive with one printed copy. Than all of this in banks safety box with insurance. Don't forget to delete copy from the computer.

how they know that the address is your? they can not steal it directly as you think they need to infect your device or steal it , which mean that you have permitted it in some way

Why not Armory?

Yes a mixture of multiple different wallets would ensure the extreme high amount in parts.
Some basic considerations.
1. Different addresses from different wallet types.
2. Manageable small amount in multiple address adds extra security.
3. Usual things of bitcoin protections:
  a. Cold storage.
  b. Never been online bitcoin address
  c. Strong encryption Password

I wouldn't store a large amount of coins all in one wallet. Split them up into smaller chunks, write down the seeds of each and keep several back ups. That way you're safe and protected.

Splitting up into small amounts of bitcoins will incur high amount of fees and managing paper wallet of multiple addresses are a headache.

See here, a single address hold how many bitcoins...
https://blockchain.info/address/3Nxwenay9Z8Lc9JBiywExpnEFiLp6Afp8v (https://blockchain.info/address/3Nxwenay9Z8Lc9JBiywExpnEFiLp6Afp8v)

Encryption alone is more than enough in my view.

Multisig does nothing for you if you don't secure the private keys. If you're using a 2 of 3 multisig (typical), and store 2 of the keys is a safe deposit box, then this is the exact same security as storing the private key of a regular wallet in that safe deposit box.

In order to take advantage of Multisig (for security),  you have to store the 3 (for a 2 of 3) keys in 3 different places. For example, store one in a safe deposit box, the second in secure place at your home (e.g. a floor safe), and the 3rd with a trusted friend. Then, if any one of those 3 keys gets compromised (e.g. copied) or lost, you quickly use the remaining 2 to transfer the bitcoin to a new secure wallet.

hmm i never thought about it as i never had such amount of bitcoins that i would have to decide where to put it in order to make them safe though in my opinion i would either make a paper wallet on a trusted online website with a computer that has never been used before or i would just buy a cold storage wallet that hardware one though it would cost a decent amount of money

It makes sense to use multiple paper wallets. For example, if you have 10BTC, store it in ten 1BTC paper wallets. When you need some spending money, take one of the paper wallets and transfer it all (don't try to extract only part of a paper wallet) to your "hot" wallet. You will then still have 90% of your stash secure.

There are many many addresses that hold more than 200 btc.  Take a look here:  http://www.bitcoinrichlist.com/

There are addresses that hold 10,000 bitcoins.  Some of these coins have not moved since 2011.  I would not be afraid of hackers if you generate the keys in a safe manner.

i think localbitcoins.com is the safest option

hell no!! never put all your eggs in the same basket!! :P

I always recommend to store them into different wallets, you know, just split it on all of them, thats the best way to be quiet about it.

You have a bit of  a problem... you ask in your main post, for the most secure way to store your Bitcoins and in another you want the convenience of spending it quickly. In that

scenario I would go for the Trezor and not the paper wallet option for everything. I would also still store a big percentage of the coins in cold storage. 

It's not easy to find a perfect balance, but you know your spending habits. Just adjust the amount based on that. I go for a 60/40 split... 60% goes into cold storage.

Armory cold storage is very good. It is no more secure than Trezor but it is more private. The problem is you need to run two computers to use cold storage in Armory, one always kept offline. The Armory devs keep talking about Trezor support but will believe it when I see it.

well your coins cant be safe all the time as there is a very very tiny chance that the same private key can be generated for other user what means that he would have the access to your wallet, without this i would recommend you to use armory wallet as its free and everyone can use it to secure your bitcoins

Install Electrum on an offline pc and save the seed either on a piece of paper or on an encrypted file on an USB key. Store several copies of your paper wallet/USB keys in SAFE places, each one being geographically distant from the others.

scammer! be carefull with him!

A Paper wallet would be the safest way to go. No viruses, and no hard drive faliure. I've personally printed one and sealed it in plastic and it's at the bottom of my fridge, so it's climate-controlled and it's protected by the plastic. Who would steal my fridge?

Very nice idea to save the wallet at the bottom of fridge. my point is there is nothing extremely safe in the world to store the bitcoins. The thief and the scammers are having very smart brain to steal the things what they want and they don't care about the punishment, their family too when they are caught red handed.

The safest bitcoin wallet is definitely a hardware wallet. You definitely need more than 1 wallet if you want to keep your bitcoins safe.

I would never store a paper wallet under an electronic appliance. Worst of Worst, what happens if the refrigerator has a leak and the private key can't be scanned. There goes a $1,000,000 or whatever large numerical value your bitcoins are worth. There are a few safe of storing large amounts of bitcoins.
Paper Wallets, Cold Storage on an offline computer, and Hardware wallets are the best methods of storing your bitcoin.
-My preferred method is a paper wallet deposited in a Bank's Safety Box.

Hardware wallet is the way to go, if you got extremely high amount of money, then you can buy some and split your money in the hardware wallet
Otherwise, splitting your money to a lot of desktop pc could also help, as long you don't brag that you got a lot of money, then a hacker maybe hack your PC.
Paper Wallet is fine too, if you could save it in a safe place that out of things that could destroy the paper

nothing perfect system in this world,and also security of bitcoin storage,because of that,i just give suggestion, you should keep your bitcoin massive numbers in some storage, hardware online wallet and wallet, or perhaps save it in papper wallet as well, it will make your bitcoin safe.