What is the heck is a private key...exactly? Someone help please.

[tovarco]

Ok.  I got the Nano S.  The public key is the wallet address given to the exchange where the BTC will come from.  The 8-digit code to open the Nano S is the pin.  The 24 phrases are used in case I lose my private key...yes?  Still not sure what my private key is exactly.  I also saw in some places where they said Ledger does not give you the private key.  So more confusion. 

[1714188603]

1714188603

[ranochigo]

The 24 phrases are used in case I lose my private key...yes?  Still not sure what my private key is exactly.  I also saw in some places where they said Ledger does not give you the private key.  So more confusion. 

The 24 words seed is used to generate the private key. The private key still exists and it is the reason why you can send the Bitcoins from the address you own. The private key comes with a public key and the private key is used to prove that you're able to spend the funds that's associated with the public key/public key hash.

With most wallets, you don't have to be concerned about private keys. It would suffice to just keep the phrases given to you safe.

[Stalker22]

As in any other cryptography, you need a private/public key pair. The public key is used to encrypt, and the private key is used to decrypt messages.
So with cryptocurrencies, you sign a transaction with a private key to confirm its validity.
The primary function of a hardware wallet is to store your private keys away from anyone. They are secure from hackers because these devices are not connected to the internet. Private keys are often stored in the protected area of a microcontroller, PIN protected and by an optional passphrase, and cannot be transferred out of the device in plain text.
If you lose your hardware wallet, you can use the seed phrase to regenerate your private key, or you can transfer your private key to another devce. That is why it is important that the seed phrase is stored in a highly protected area. This is the most important piece of information that gives full access to your funds in your wallet.

[webtricks]

The 24 phrases are used in case I lose my private key...yes?  Still not sure what my private key is exactly.

Not exactly! Let me explain with little background:

Earlier, single private/public keys pair were used for sending/receiving bitcoin. A random large number was used as private key, a public key was derived from it using Elliptic Curve Cryptography and then public key was hashed to generate bitcoin address. Bitcoin transaction was signed using private key.

However, with time people realized that using single bitcoin address could be dangerous for privacy. Hence, the concept of 'one address, one input' came out. This means user has to create new bitcoin address every time he receives bitcoin. To do so, user has to create new private key (a large random number) every time. So, the user has to maintain and store the record of all private keys with each new address which could be very cumbersome.

Hence, the company behind Trezor wallet suggested the concept of seed phrase. Under the concept of seed phrase, a random large number is used to generate random sequence of 12-24 words known as seed phrase. Then this phrase is used to generate new private key and new bitcoin address every time bitcoin is received. Most of the wallets handles the key generation process automatically. New private key is generated and stored which is automatically used to sign the transaction. So, you as the user don't have to worry about private keys since your wallet is already storing private key of all your bitcoin addresses. All you need to do is to store seed phrase safely. Every time you import this phrase, wallet will automatically generate all your private keys and bitcoin addresses.

[blue Snow]

Still not sure what my private key is exactly.  I also saw in some places where they said Ledger does not give you the private key.  So more confusion. 

This is an example of your public key - 1D7sLmEpzUKkZT2YFsDNZtXZEQax3LiWt1
This is an example of your private key - L5HWPGe9hwLrkWGAppL1HxoaVBSHMQMfadT9uX1S3Nx3F2DHZwXc
(of course, that address has 0 balance and never used, this address created for example purposes)

If you want to sign a transaction, you need a private key.

your private key is in the ledger wallet, it doesn't show you in PC. the private key is a child key generate from master private key where generated from your 24 seed. so, what the important is you have to keep your 24 seed in a safe world, just it.

[mardaed]

That's not true that the Ledger won't give you the private key, I think you missed it maybe they say "Never share your private key to others" right? Those 24 words are the important ones if you missed those you won't be able to open your wallet and you will not get your private key for a certain wallet.

An example:

Pin = Open your ledger
24 Phrase Words = Are the password to open your Bitcoin wallet where in that Bitcoin wallet can have many addresses (your address)
Private key = A password of your BTC address



*Note: Every address have it's own private key
**Note: Those address generated on your wallet came from your 24 Phrase words.
***Important Note: Never share your 24 Phrase words and Private key to anyone, If anyone ask it from you even the Ledger (either on email) they are a fake ones and will just scam you.

[o_e_l_e_o]

That's not true that the Ledger won't give you the private key

It is true. You cannot extract your private keys from a Ledger device - if you could, then it defeats the entire purpose of them being stored securely on the device. The only way to get your private keys from the seed phrase a Ledger device generated is to use a third party piece of software and enter your seed phrase to derive your private keys. You cannot extract them directly from the device itself.

24 Phrase Words = Are the password to open your Bitcoin wallet where in that Bitcoin wallet can have many addresses (your address)

That's a misleading way to explain things. Yes, the seed phrase can recover your bitcoin wallet, but it is not a "password" to that wallet, and you do not need to enter it every time you access the wallet as you would with a real password.

-image-

That image is also very misleading. The seed phrase does not generate addresses first and then private keys to those addresses. The seed phrase generates a master private key, which is used to generate individual private keys, which are used to generate individual public keys, which are finally used to generate addresses.

If the data is encrypted with a private key, then decrypt it using the Public key.

Wrong way round. Data is encrypted with public keys and decrypted with private keys.

[acquafredda]

We have 2^256 different possible combinations of private keys and 2^160 combinations of addresses. This means that for every bitcoin address there are approximately (2^256)/(2^160)= 2^96 private keys.
I always like to remind myself about these huge sizes!
Anyway, you will probably never have to handle private keys, instead you will typically be given a seed phrase that encodes the same information as private keys. That is the reason why you need to safely store those words and in case you lose them empty the wallet to another one you control to avoid being robbed if somebody can access your seed.

[Kupid002]

Ok.  I got the Nano S.  The public key is the wallet address given to the exchange where the BTC will come from.  The 8-digit code to open the Nano S is the pin.  The 24 phrases are used in case I lose my private key...yes?  Still not sure what my private key is exactly.  I also saw in some places where they said Ledger does not give you the private key.  So more confusion. 

That phrase is enough to secure your holding other altcoin have such option as private key that you can stored like ethereum but in BTC that's enough , this is also what other wallet asked once you want to open your wallet in other Bitcoin wallet using pass phrase.

[Mike Mayor]

As far as I know, you only need your pin & the 24-word phrase. I don't fully understand the private key thing I thought the 24-word phrase was the private key? I have the pin and 24-word phrases backed up 3x in different parts of my house my family has access to one as well. (incase something shall happen to me they can still use my coins) I think the private key is never exposed and is in the nano s, not even you need to see it. To me that makes sense. Unless I am greatly confused then please help me out. 

[20kevin20]

As far as I know, you only need your pin & the 24-word phrase. I don't fully understand the private key thing I thought the 24-word phrase was the private key?

No, they're not the same thing. When you enter a seed into a wallet, you generate multiple addresses as per your need. A private key gives you access to only one address.

I think the private key is never exposed and is in the nano s, not even you need to see it. To me that makes sense. Unless I am greatly confused then please help me out.  

Well, if the seed was the private key and the Ledger never showed it to you, you'd never have a way to recover your funds.

Private keys are a string of alphanumeric characters (a-Z and 0-9) giving you access to one specific address. This is why it's advisable to sweep a paper wallet: if you import the private key into Electrum and spend part of the paper wallet directly from it without coin control, chances are your change will go into an address you don't own because you only own one address (the one you're spending from).

Example of private key: 5Kb8kLf9zgWQnogidDA76MzPL6TsZZY36hWXMssSzNydYXYB9KF
Example of seed: witch collapse practice feed shame open despair creek road again ice least
(source: Bitcoin Wiki)

[webtricks]

Example of private key: 5Kb8kLf9zgWQnogidDA76MzPL6TsZZY36hWXMssSzNydYXYB9KF

This is not a private key, this is Wallet Import Format (WIF) of private key. More technically, it is a Base58 encoding of private key along with mainnet byte and checksum. You can't directly sign bitcoin transaction with WIF. You first have to decode private key from WIF to sign the transaction. The reason why wallets prefer WIF over bare private keys for importing address is because WIF is more compact and has checksum in the end. So if user makes mistake and mistypes any character of WIF, the wallet will instantly know that WIF is incorrect. Moreover, WIF helps wallet to determine whether to generate 'compressed public key' or 'uncompressed public key' from private key.

Private keys are a string of alphanumeric characters (a-Z and 0-9) giving you access to one specific address.

Private key is not a string, it is a number! You need a valid number as a private key to sign a bitcoin transaction.

Example of private key: 2 or 54119949161611191 or 778257527527527527257252752725.

In fact, any number from 1 to 115792089237316195423570985008687907852837564279074904382605163141518161494336 is a valid private key.

We can also represent private key in hexadecimal, in such case any number from 0x1 to 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364140 is a valid private key.

[yayayo]

Here this video may help you out to understand it https://www.youtube.com/watch?v=aPprQUQljHE they were using simple explanations to understand it easily by their viewers
I hope this would help you out.

ya.ya.yo!

[o_e_l_e_o]

This is not a private key, this is Wallet Import Format (WIF) of private key.

In fact, any number from 1 to 115792089237316195423570985008687907852837564279074904382605163141518161494336 is a valid private key.

I'm going to be pedantic here, but you can't say that WIF is not a private key, but also say that a decimal string is a private key. They are both essentially the same thing - a different way of representing a 64 character hexadecimal number. Either you say that only the hexadecimal number is a true private key, and any other representation of it (be that WIF, Base10, Base2, minikey, whatever) is not a private key, or you say that any way of encoding that hexadecimal number is a private key. It doesn't make sense to say that Base10 is a private key but WIF isn't. I'd argue that WIF has far more of a claim to be a real private key since that is the format that most wallets accept when you import keys, and most wallets will provide when you export keys.

[fiulpro]

A private key is like a 24 word ownership document.  If you accidentally loose access to your wallet then you can very easily use that ownership to get your Bitcoins back.

It's a super important part of having the Bitcoins in wallets , so that is why you often see the phrase *not your keys, not your coins*. So if you are using a wallet which doesn't give you access to your Private Key that does mean that the real ownership of the Bitcoins is actually with the wallet company and not with you.

Every wallet has a different private key, it is super important to know what's yours, Never share it with anyone !!!!!

[jademaxxiss012]

Try to read more about bitcoin addresses. Yes, it is a little bit complicated if you are new just like when I was also new to bitcoin. However, after the first transaction I made I was able to understand how things work but still commit errors especially sending a wrong amount or wrong wallet addresses.

Now, if you wanted to learn more about bitcoin addresses you can use the google search engine for this and learn what are the different kinds of bitcoin addresses. In this way after reading some of it you will be able to find out and even apply the things that it was being suggested or laid out what to do. Try to make also your first transaction with a small amount so that you can verify whether the things you learn is right or that you are doing things right.

[o_e_l_e_o]

A private key is like a 24 word ownership document.

A private key and a seed phrase are not the same thing. A private key backs up a single address. A seed phrase backs up every address in that wallet.

It's a super important part of having the Bitcoins in wallets

Bitcoin is not stored in wallets. Bitcoin is stored on the blockchain. The only thing which is stored in wallet is the private keys which allow you to interact with specific amounts of bitcoin on the blockchain.

Every wallet has a different private key, it is super important to know what's yours, Never share it with anyone !!!!!

Every address has a different private key. Every wallet has a different seed phrase.

[cheezcarls]

Private key is your permanent password that cannot be changed and only you are the owner of it. Once someone has access to your private key, there’s no way that you can change it. That person will forever have access to it, especially if you are sharing it to your family members. This was designed for pure ownership where you have the freedom to move your coins or tokens without third party interference like what the banks do.

[Stalker22]

A private key is like a 24 word ownership document.

A private key and a seed phrase are not the same thing. A private key backs up a single address. A seed phrase backs up every address in that wallet.

It's a super important part of having the Bitcoins in wallets

Bitcoin is not stored in wallets. Bitcoin is stored on the blockchain. The only thing which is stored in wallet is the private keys which allow you to interact with specific amounts of bitcoin on the blockchain.

Every wallet has a different private key, it is super important to know what's yours, Never share it with anyone !!!!!

Every address has a different private key. Every wallet has a different seed phrase.

This!
It's very odd to see a senior member of this forum give such shallow and inaccurate answers. These are the fundamentals of cryptocurrencies, and I'm sure one Hero ranked member knows better than that.

Hell, even I, with my humble experience, know the difference between a seed phrase and a private key! 

[webtricks]

This is not a private key, this is Wallet Import Format (WIF) of private key.

In fact, any number from 1 to 115792089237316195423570985008687907852837564279074904382605163141518161494336 is a valid private key.

I'm going to be pedantic here, but you can't say that WIF is not a private key, but also say that a decimal string is a private key. They are both essentially the same thing - a different way of representing a 64 character hexadecimal number. Either you say that only the hexadecimal number is a true private key, and any other representation of it (be that WIF, Base10, Base2, minikey, whatever) is not a private key, or you say that any way of encoding that hexadecimal number is a private key. It doesn't make sense to say that Base10 is a private key but WIF isn't. I'd argue that WIF has far more of a claim to be a real private key since that is the format that most wallets accept when you import keys, and most wallets will provide when you export keys.

WIF is not the representation of 64-character hexadecimal number. It is a representation of 74/76 character hexadecimal number. It includes additional network byte and 4-bytes checksum. So, it includes private key but WIF itself isn't the representation of private key. IMO, the better term for WIF would be special formatting of private key.

While generating signature using ECDSA,
s = k^-1(z+rd_A) mod n

where, d_A is a private key i.e. an integer between [0,n].

In the calculation of s, (r * d_A) is a normal (non-ECC) multiplication. So in most of the ECDSA implementation, d_A is taken in Base10 to make the multiplication possible.

So for me,
private key = d_A = a random integer between [0,n]

Encoding the integer in either Base10 or hexadecimal or Base2 doesn't make the difference, it is still the same integer in any representation. However, WIF and minikey are not the representation of same integer. These are special formats. WIF needs to be decoded from Base58 and network byte & checksum need to be dropped to get the integer. Whereas, in minikey, SHA256 hash of the string has to be calculated and the resulting hash is assumed as integer in hexadecimal.