Need to know more about cold storage

[redsn0w]

Hello!
Thanks all for your answers and another question was arose

The best cold storage is to print your private keys on a paper (don't mention on it that it is Bitcoin-related), copy it several times and store these papers on several locations. To be safe, make a USB copy additionally. Finally, delete the private keys from your laptop, if you use it to get into the internet

It seems a lot of you don't understand that a cold wallet/storage private key should never be used or exposed online . If it is exposed online than it loss the cold property and it "is not more secure". For generate a real cold address you should choose a "secure" machine with windows (maybe better linux) and "use" bitAddress or client/wallet (downloaded from another machine, and transferred through USB or other storage supports) to generate your offline address. The final thing to do is send your bitcoin to that address and protect your laptop with several "copy" of your private key (into a sheet of paper, cd, floppy, sd,etc...); a real private key of a "cold" wallet address should never be exposed online.

Exactly. I'm surprised how many people think they have "cold storage" just because it isn't readily connected to the internet.

Never let your private key touch an internet connected machine. If you spend from your cold wallet, it's no longer cold and you should move your remaining coins to a new cold address. Personally, I generate my cold addresses with dice, and then convert that base 6 key offline so I can get the public address. The private key is never saved or printed or connected to the internet, I have my private key written in my 99 dice rolls.

If a wallet which is never connected to internet, then how that offline wallet contains BTC?

Cold storage transactions are off blockchain?

~Rude Boy

No, it isn't. All transactions will be on-chain.

See above, How to transfer BTC to an offline wallet which is never connected to internet (here don't bother about hard wallets). If yes, then this transaction is off-chain transaction right?

~Rude Boy

Do you know how a transaction works and where are stored your bitcoin? I will give an help, the bitcoin are stored in the blockchain so when you send a tx to a cold address (check any by block explorer) you will find that your btc is in that address. When you want to "move" the btc in that address  (also if you don't see them in your offline wallet, you should only sign a raw transaction and push/broadcast it on any other device (connected to Internet).

[Muhammed Zakir]

See above, How to transfer BTC to an offline wallet which is never connected to internet (here don't bother about hard wallets). If yes, then this transaction is off-chain transaction right?

~Rude Boy

See redsn0w's answer first.

You misunderstood what is "off-chain" transaction.

Off-chain transactions are transactions which isn't stored in "Blockchain". When you do an off-chain transaction, the Bitcoins aren't "really" being moved. You are only getting a confirmation receipt from the company. Off-chain transactions are generally bad and it contradicts some of Bitcoin rules:

• You need to trust the company or person who handle off-chain transaction.
• Off-chain transactions are reversible.
• Off-chain transactions promote & focus on centralization.
• Off-chain transactions don't have public proof(aka ledger).

There maybe more but I think this is more than enough.

If you didn't understand redsn0w's correctly, here is an answer from Stackexchange.

The "blockchain" is a constantly growing database of transaction information which is sent out to all nodes in the Bitcoin network. When you perform a transaction, that transaction is distributed to the network and assuming the transaction is valid, will be included in the next "block." This is where the coins themselves are stored. When you initiate a transaction, all previous transactions to or from that address are scanned and a balance is calculated. If your transaction exceeds this available balance, it will be rejected by the network and will not be included in a block.

It's also important to note that the blockchain technically doesn't store "coins" it stores transaction information. The coins themselves are not discrete things which need storage - when coins are mined the miner's balance is credited via a "generate" transaction which adds to his or her available balance. When coins are sent from A to B, that transaction subtracts from A's balance and adds to B's balance. This is similar to the way that your employer may, via EFT, send "money" to your bank and you can use your debit card to spend that "money" in a store, all without anyone ever seeing a discrete physical dollar bill. Most money in the world today exists merely as transaction histories and balances - Bitcoin is no exception.

Edit: Added few words.

[Amph]

If a wallet which is never connected to internet, then how that offline wallet contains BTC?

See above, How to transfer BTC to an offline wallet which is never connected to internet (here don't bother about hard wallets). If yes, then this transaction is off-chain transaction right?

first of all the wallet does not contain anything, but just private key that you need to access to your bitcoin in the blockchain

imagines that the wallet is like a bunch of keys and the blockchain is a chain of many safe box all connected, inside every safe box there are 25 btc(those 25 can belongs to multiple person)

now to retrieve those you need the correct key associated(or many keys for every box, if the btc inside it belongs to more than one person, which is usually the case)

if you have the key you can access the box with your funds and if your funds are splitted among many safe box, you need more keys

so you actually never transfer anything to an offline wallet, you transfer them to the correct safe box, which your key is associated with

[coinableS]

If a wallet which is never connected to internet, then how that offline wallet contains BTC?

See above, How to transfer BTC to an offline wallet which is never connected to internet (here don't bother about hard wallets). If yes, then this transaction is off-chain transaction right?

~Rude Boy

Okay I think I see where your confusion is.
So for your cold storage address all you need is the public key aka bitcoin address. This can be generated completely offline, the only thing you need to do is then go to your hot wallet and send coins to that cold address you just created. Now your coins are in an address where the private key has never seen the internet. The transaction will be on the blockchain, and everyone running a node will know that you sent bitcoin to that address.

[Muhammed Zakir]

first of all the wallet does not contain anything, but just private key that you need to access to your bitcoin in the blockchain

imagines that the wallet is like a bunch of keys and the blockchain is a chain of many safe box all connected, inside every safe box there are 25 btc(those 25 can belongs to multiple person)

now to retrieve those you need the correct key associated(or many keys for every box, if the btc inside it belongs to more than one person, which is usually the case)

if you have the key you can access the box with your funds and if your funds are splitted among many safe box, you need more key

so you actually never transfer anything to an offline wallet, you transfer them to the correct safe box, which your key is associated with

First, I though you meant "blocks" by saying "box", then when you said "keys", I understand you were saying about addresses. If it is, see below.

Okay I think I see where your confusion is.
So for your cold storage address all you need is the public key aka bitcoin address. This can be generated completely offline, the only thing you need to do is then go to your hot wallet and send coins to that cold address you just created. Now your coins are in an address where the private key has never seen the internet. The transaction will be on the blockchain, and everyone running a node will know that you sent bitcoin to that address.

Bitcoins aren't stored in Bitcoin "addresses", coins are stored in "blocks". However,

"It's also important to note that the blockchain technically doesn't store "coins" it stores transaction information. The coins themselves are not discrete things which need storage."

So how where are Bitcoins stored? Technically, "nowhere".

"When coins are sent from A to B, that transaction subtracts from A's balance and adds to B's balance. This is similar to the way that your employer may, via EFT, send "money" to your bank and you can use your debit card to spend that "money" in a store, all without anyone ever seeing a discrete physical dollar bill. Most money in the world today exists merely as transaction histories and balances - Bitcoin is no exception."

[Amph]

first of all the wallet does not contain anything, but just private key that you need to access to your bitcoin in the blockchain

imagines that the wallet is like a bunch of keys and the blockchain is a chain of many safe box all connected, inside every safe box there are 25 btc(those 25 can belongs to multiple person)

now to retrieve those you need the correct key associated(or many keys for every box, if the btc inside it belongs to more than one person, which is usually the case)

if you have the key you can access the box with your funds and if your funds are splitted among many safe box, you need more key

so you actually never transfer anything to an offline wallet, you transfer them to the correct safe box, which your key is associated with

First, I though you meant "blocks" by saying "box", then when you said "keys", I understand you were saying about addresses. If it is, see below.

yeah was just an analogy, to make him understand faster

i like to compare the blochain to a chain of these

where inside there is the reward, and you need a private key(which in the safe box is a combination/key) to access your fund)

the only difference is that the blockchain is made of safe box that can be accessed by many people , so it's not just your

and therefore every "safe box" in the block chain has more combination/keys, one for every private key existing, that is associate to the reward inside it

[LiteCoinGuy]

https://www.youtube.com/watch?v=I1uefzJJ6nM

[Webnet]

u can find all info u need on official bitcoin documentation
https://en.bitcoin.it/wiki/Cold_storage
https://en.bitcoin.it/wiki/How_to_set_up_a_secure_offline_savings_wallet