Topic: Missing Private Key (Read 1086 times)

It's important to create a backup of your wallet on a regular basis in case something should happen to your computer.  The backup will contain all of your private keys, addresses, and transactions.  You can create the backup in Bitcoin Core from the "File" menu.


The private key is a number that is mathematically associated with the public key in a way that makes it possible to re-generate the public key if you only have the private key.  However, it is impossible with any currently known mathematics to calculate the private key if you only have the public key.  The mathematical relationship makes it possible to use the private key to mathematically calculate a signature value on arbitrary data.  Given the signature and the public key it is possible to verify that the signature and the public key are both associated with the same private key.

This signature process is used by bitcoin to validate the inputs to transactions, it provides a way for the spender to prove that they are authorized to spend those inputs.  If the owner of the bitcoins loses their private keys they will no longer be able to generate valid signatures, and therefore will not be able to spend their bitcoins at all. If anyone else gains access to the private keys, they will be able to create valid signatures and therefore will be able to authorize the spending/stealing of funds.


There is no known way to calculate a properly generated private key from the public key or from a properly created signature.

However, if I know my own private key, it's possible for me to (accidentally or intentionally) leave clues to what the value might be.  Using those clues others might be able to reduce the set of possible private keys to something small enough that they could search all the possibilities until they find the right value.

It is also possible for me to use a cryptographically insecure method of generating my private key.  Others can then try to guess the method I used so they can re-create the same private key.  If I want it to be a game, I can then leave clues about the method I chose for generating the key.

Also a neat feature is some hardware wallets work with MyCellium on android.  I have done a hands on with two of them.

Trezor: https://bitcointalksearch.org/topic/hands-on-trezor-hardware-wallet-notlist3d-1298917
Ledger Nano: https://bitcointalksearch.org/topic/hands-on-ledger-nano-hardware-wallet-notlist3d-1305888

you can instal mycellium bitcoin wallet at your mobile device
https://play.google.com/store/apps/details?id=com.mycelium.wallet

you can back up your private key and you get full acces to your bitcoin addres

The private key is a very very large random number. It is one of 2^256 - 1 numbers. The human mind is not capable of fathoming such large numbers, so just trust that it is insanely huge. Since there are so many of these very very large random numbers, the odds of someone finding a private key associated with an address that can be spent from and is found within a person's lifetime is very low.

What game are you talking about?

Ok, thanks for the info, but what is the private key?  I seen on here that there is a game where people are trying to crack bitcoin addresses to get rewards.  How private can it be if people are cracking them?

You can export your private key in the debug console, however, don't do that. It is intentionally made difficult to do so that people don't do it and compromise their security.

You can get more addresses by clicking the "new" button in File > Receiving Addresses.

I have read this before and I have downloaded the BitCoin client, so how do I identify my private key here?  I also noticed with my wallet, I only have one bitcoin address, how do I have so many more on CoinBase?

The 12 word combination is the seed that is used for generating the private keys.  Every bitcoin address in the wallet will have its own private key, but anyone with access to the seed can generate all those private keys.  This is how the the 12 word combination "recovers the wallet".  The wallet uses the seed to re-generate all the private keys and addresses.  Therefore, as long as you have that seed there is no need to backup private keys individually. Also, it is important to keep that seed as safe and secure as you would the private keys themselves.  Anyone that gains access to the seed can steal all your bitcoins.


That sounds high.  Typically I'd expect such a transaction to have a fee no larger than 0.0001 BTC.  Are you sure it wasn't 0.00006 BTC?


The fee is relative to the size of the transaction in bytes not in bitcoins. Generally the fees are calculated on a "per kilobyte" basis. It is possible to have a very small value transaction (for example 0.00001 BTC) that is more than 10 kilobytes in size.  It is also possible to have a very high value transaction (for example 100 BTC) that is less than 300 bytes in size. The size (in bytes) of the transaction depends on the number of inputs and number of outputs in the transaction, and not on the quantity of bitcoins.

Ok - I set up electrum and sent over .01 BTC as a test. Couple more questions...

The private key, is that the 12 word combination I was told to write down? Or is that used just used for recovering the wallet?


I also did another test transfer from Electrum to my Coinbase account. I intended to send the .01 BTC, but Electrum wouldn't let me send it with any less that a 0.0006 BTC fee. Is this normal? Those are high fees if you intend to use the wallet much at all. And is the fee relative to how large the transaction is? if I sent 1 BTC would it charge me .06?





Thanks guys

Most of the online wallets were using shared wallet. So they won't let you see/manage private keys of your bitcoin address. So it is not recommended to use an online wallet as your primary wallet unless you're doing frequent transaction.

Coinbase is partially due to their insurance policy.   As long as it's Coinbase hacked and not your account where it's your fault they are suppose to have a insurance policy to cover it.  If they gave out private key it would defeat their idea of how they keep it secure.

But you are 100 percent trusting Coinbase with your coins as without having private key nothing you can do to recover if they ran off or something (which granted is very small possibility).   

No, your wallet address is the public key. You need to keep your private key secret. If you lost your private key, then your Bitcoins are gone forever.

Maybe this will help: Public Addresses And Private Keys

You don't have any bitcoins.

You have donated your bitcoins to a business called Xapo.  Those bitcoins now belong to Xapo and they can do whatever they want with them.  You have no control over what they do with your bitcoins.

In exchange for your donation, Xapo has provided you with an account on their website.  They have given you a promise that they will send an amount of their bitcoins equivalent to your donation wherever you ask them to send to (assuming that the destination is not in violation of their terms of service).  You have decided to believe this promise from them.

If Xapo gets shut down by the government, they may become unable to honor their promise to you.
If Xapo is hacked and loses control over a large number of their bitcoins, they may become unable to honor their promise to you.
If Xapo is run by incompetent people and they lose control over a large number of their bitcoins, they may become unable to honor their promise to you.
If Xapo has any criminals on staff that steal a large number of their bitcoins, they may become unable to honor their promise to you.

If you prefer to actually have bitcoins (instead of just a promise from a company that you have little access to and know very little about), you should consider installing bitcoin wallet software and having the bitcoins sent to your wallet.

Note that running your own wallet comes with it's own risks.  Right now you are trusting Xapo to know more than you about how to secure the private keys against loss, theft, or destruction.  If you run your own wallet, you are 100% responsible for keeping the private keys secure.  If you lose access to the private keys (destroyed in a fire, tornado, earthquake, flood, hard drive crash, or simply misplaced,) or if they are stolen or copied by malware, then you will permanently loose access to your bitcoins with no way to recover them.

Wow - thanks for the info and quick responses guys.

I'll look into Electrum now.

What you're using are not actual wallets but wallet service providers. Think of them as a bank, the funds you're storing into them are not fully under your control.

You can read more on private key and its importance here: https://en.bitcoin.it/wiki/Private_key

private key is like a key or secret password that can grant access to your saved up money (bitcoin stored in your bitcoin address). so anybody who have access to that key have also access to the coins.

if you are using coinbase or xapo, you don't have private keys but you have an account on their website with a username and password. in other words a third party is handling your coins.

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

coinbase and xapo doesnt give you full control over your private key, dont use them to store large amount of bitcoins

A private key is the actual address of the BTC.. where as the address you are used to is actually the public address.

I highly suggest looking into electrum or some other wallet you have access to the private keys with.

Hey All -

I started buying BTC about a month ago in a Coinbase account. I have transferred some of the BTC to Xapo...

I keep seeing people mention how important it is to not lose your private key. To write it down and put it in a safe deposit box.

What is the private key? Is it just my wallet address?

Thanks!