Will my private key be seen by everyone on the network?

[Abbatty]

I have been reading trying to learn about bitcoin and  I read that the private key is a collection of letters and numbers that are specifically linked to a single individual and are used to verify transactions and prove ownership of a bitcoin address if i am not wrong So, in order to be able to spend the bitcoins received when a certain amount is transferred to a bitcoin address, the owner must use the private key linked to the address to validate the transaction and confirm he owns the address. However, I later discovered here that private keys are meant to be kept private and only known by the owner in order to prevent unauthorised access to your coins.

So i have a few questions which i am not yet clear about please i need clarifications.

So when verifying the transaction using your private key will the private key be known or seen by others on the network? If so then is it not risky letting others know our private keys.

And also in a case where the owner loses his/her private key and is unable to verify the transaction what will happen to the coins. Are they gone forever? Or is there a way to recover the private key.

[Zaguru12]

So when verifying the transaction using your private key will the private key be known or seen by others on the network? If so then is it not risky letting others know our private keys.

The private key is not visible during transaction verification because it is not basically what you sent with the transaction data to the nodes or miners. What you sent is a digital signature and a public key. This two prove ownership that the transaction belongs to you. The digital signature is created by signing or hashing a transaction data with your private key internally and then you proceed by sending this three item (transaction data, digital signature and public key) to the nodes to prove ownership

And also in a case where the owner loses his/her private key and is unable to verify the transaction what will happen to the coins. Are they gone forever? Or is there a way to recover the private key.

If you didn’t back up your seed phrase or private key and that wallet that contains it got deleted from the device or the device got lost then it cannot be recovered as the only way to recover your wallet is through private key or seed phrase

But if you have your private key or seed phrase somewhere probably offline(which is the best place to save them) you can easily just import them into another wallet

[CryptopreneurBrainboss]

So when verifying the transaction using your private key will the private key be known or seen by others on the network? If so then is it not risky letting others know our private keys.

Nope they won't be known, they won't be called private key if they will be exposed when you used them to authorize a transaction from your wallet. You're the only one that should know your private key and they should be stored offline.

And also in a case where the owner loses his/her private key and is unable to verify the transaction what will happen to the coins. Are they gone forever? Or is there a way to recover the private key.

They're gone forever and don't believe any service offering to recover your private key for you because they're scammers and in a situation they do recover the keys for you (very unlikely to happen) why do you think they'll send you back the coins?

[Nheer]

Of course, the entire network will be able to see a transaction when it is being validated to ensure that the public key and the private key used to prove ownership match. However, as you pointed out, a private key is meant to be kept private since it acts more like a personal password required to access your coins. Therefore, when signing a transaction, you can use something called a "Digital Signature" rather than using your private key for everyone to see.

The digital signature is derived from the private key and serves as a substitute to the private key when proving ownership so you don't reveal your private key to everyone on the network. Here is a post for you that best explains signing transaction and digital signature.

https://bitcointalk.org/index.php?topic=5461728.msg62634095#msg62634095 for further details check  https://learnmeabitcoin.com/beginners/digital_signatures

Regarding your second question, please be aware that there is no way to recover your private key once you have lost it, meaning you will never again be able to access your bitcoins.

[BitMaxz]

Take note private key should be kept secret it shouldn't be shared with anyone if you want to prove that you own that address you need to make a signed message with your public key address it would generate a signature that you can provide to anyone who wants to verify that you own that address.
And private keys are not used to verify and validate a transaction only nodes and miners are responsible for validating and verifying transactions, not the private keys.

About the private key if it is seen on the explorer no what you can see on the explorer are the public keys(the sender and receiver's address) and the amount of BTC you sent, etc. Not the private keys like I said it should be kept secret and if you lose this key you won't be able to sign a transaction and yes it's gone forever if you lost this key.

[Stalker22]

So when verifying the transaction using your private key will the private key be known or seen by others on the network? If so then is it not risky letting others know our private keys.

The private key should remain secret and you should never share it with anyone.  That is an important part for safety of your cryptocurrency. 

What you give out to people is your public address, which is derived from your private key and  when you use your private key to sign transaction on the blockchain, it lets the network know that you signed it with your private key without you having to show the actual private key to anyone.  That is a core thing of how asymmetric encryption works that makes cryptocurrency secure.

So remember, keep that private key private and dont show it to anybody no matter what.

And also in a case where the owner loses his/her private key and is unable to verify the transaction what will happen to the coins. Are they gone forever? Or is there a way to recover the private key.

The private key is not used to verify, but to cryptographically sign transactions. Without a private key, you will no longer be able to sign transactions, therefore you will not be able to spend coins from your address.

[digaran]

When you go to a bank to transfer money, do they ask for your signature and ID or not?  Public key cryptography works as a bank, but there is nobody in the middle to verify your signature and ID, it's the mathematics doing all that behind the scenes, this is why they call it crypto.

Just like there is a possibility to forge hand written signatures and even use a fake ID in banking systems, that is also possible to do in crypto, however the whole point of this system is the difficulty of doing that, this difficulty keeps our coins safe.   This is "decentralized, trust-less" banking.

[Charles-Tim]

Your wallet will generate you seed phrase, the seed phrase will generate private key, public key and addresses. You may not even know that your wallet generates you private key, but seed phrase can be backed up which will always generate the private key. The private key is need to have access to your coins, and seed phrase can generate it. Which means that you should protect your seed phrase and private key. Both can not be known online to anyone unless your wallet is compromised.

[Bitcoin Smith]

So when verifying the transaction using your private key will the private key be known or seen by others on the network? If so then is it not risky letting others know our private keys.

And also in a case where the owner loses his/her private key and is unable to verify the transaction what will happen to the coins. Are they gone forever? Or is there a way to recover the private key.

You don't need to use your private keys every time to access your bitcoin, technically private keys associated with the address is indeed to verify the TX and proves the ownership.

Private keys will not be visible to anyone other than you, so you are the one who should keep the keys secured and if you lost it then its impossible to access the funds but the funds in that address will always be there unless the private keys used.

You don't need to keep the private keys of your address, just the recovery seeds is enough which can be used to recover all the funds associated with the seeds along with the private keys.

[witcher_sense]

So when verifying the transaction using your private key will the private key be known or seen by others on the network? If so then is it not risky letting others know our private keys.

Transaction verification doesn't imply revealing or using one's private key, instead, it is only used during transaction signing. The signing process is an inextricable part of cryptocurrency transfer authorization: other participants of the network won't accept your transaction if it didn't get signed with the corresponding private key. To prove a transaction was signed correctly, you provide other participants with information consisting of the transaction, public key, and signature, which they use as inputs in a special formula.

And also in a case where the owner loses his/her private key and is unable to verify the transaction what will happen to the coins. Are they gone forever? Or is there a way to recover the private key.

Assuming a private key was created with a cryptographically secure random number generator, there is no reliable way to find lost private key.

[digaran]

You don't need to use your private keys every time to access your bitcoin, technically private keys associated with the address is indeed to verify the TX and proves the ownership.

Of course other than developers no one should use private key manually, but every time we send coins, our wallets use the private key to sign the tx,  private key is not verifying anything, it's just like a finger print, unique for each person, you sign/authorize access to the coins, nodes verify if you really signed it using your key.

[pooya87]

I read that the private key is a collection of letters and numbers

A private key is a big number and numbers can be represented in different ways. For example: ten, 10, 0b1010, 0xA are four different ways to represent the same number, 10.
In bitcoin we represent this number using a special encoding called Base58 which means what you see is a combination of letters and numbers.

are used to verify transactions and prove ownership of a bitcoin address

In bitcoin we use mathematics and an algorithm called Elliptic Curve Algorithm and use what's called Digital Signatures.
You create a "signature" mathematically using your private key and publish that alongside your public key that is also mathematically computed from the private key. Both of these processes are one way (meaning they are irreversible).
Others can verify the authenticity of the signature with your public key while not be able to know your private key because of how the algorithms work.

[satscraper]

Others can verify the authenticity of the signature with your public key while not be able to know your private key because of how the algorithms work.

True, providing the private key was not generated , say, with improperly-configured or bad-source RNG which  may result in low-entropy and/or predetermined entropy. Luckily modern hardware wallets  (like Passport or ColdCard MK 4) incorporate TRNGs that produce reliable 256-bit randomness  thus their owners, when making transactions, have not be worried about  brute-force of their priv keys .

[NotATether]

So when verifying the transaction using your private key will the private key be known or seen by others on the network? If so then is it not risky letting others know our private keys.

No. You verify a transaction on your local computer, so your private key does not go through the network to anyone else's computers.

And also in a case where the owner loses his/her private key and is unable to verify the transaction what will happen to the coins. Are they gone forever? Or is there a way to recover the private key.

The transaction is verified without the private key. It actually uses the public key. The asymmetric cryptography that is used to secure wallets in the bitcoin network allows us to verify the signature of a transaction if we know its public key.