[ASK] Public Key

[Farul]

What Is Public Key,And What It Used For?
I Ask Here Because There's No Bitcoin Wiki Page For This.

[Rath_]

public key: A number that corresponds to a private key, but does not need to be kept secret. A public key can be calculated from a private key, but not vice versa. A public key can be used to determine if a signature is genuine (in other words, produced with the proper key) without requiring the private key to be divulged. In Bitcoin, public keys are either compressed or uncompressed. Compressed public keys are 33 bytes, consisting of a prefix either 0x02 or 0x03, and a 256-bit integer called x. The older uncompressed keys are 65 bytes, consisting of constant prefix (0x04), followed by two 256-bit integers called x and y (2 * 32 bytes). The prefix of a compressed key allows for the y value to be derived from the x value.

There is no detailed article on public keys on the Bitcoin Wiki, but you can learn about public key cryptography from this Wikipedia entry.

[darosior]

What Is Public Key,And What It Used For?
I Ask Here Because There's No Bitcoin Wiki Page For This.

Hi,

A private key is used in a P2PKH transaction to set a condition. This condition is "check that the sender of the funds (the one who unlocks an unspent output) has the right to spend them (can produce a signature valid for this public key, meaning he has the corresponding private one)".

[apxu]

What Is Public Key,And What It Used For?
I Ask Here Because There's No Bitcoin Wiki Page For This.

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

[bitmover]

What Is Public Key,And What It Used For?
I Ask Here Because There's No Bitcoin Wiki Page For This.

From mastering bitcoin, Andreas Antonopoulos:

https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch04.asciidoc

Keys come in pairs consisting of a private (secret) key and a public key. Think of the public key as similar to a bank account number and the private key as similar to the secret PIN, or signature on a check, that provides control over the account. These digital keys are very rarely seen by the users of bitcoin. For the most part, they are stored inside the wallet file and managed by the bitcoin wallet software.

In the payment portion of a bitcoin transaction, the recipient’s public key is represented by its digital fingerprint, called a bitcoin address, which is used in the same way as the beneficiary name on a check (i.e., "Pay to the order of"). In most cases, a bitcoin address is generated from and corresponds to a public key. However, not all bitcoin addresses represent public keys; they can also represent other beneficiaries such as scripts, as we will see later in this chapter. This way, bitcoin addresses abstract the recipient of funds, making transaction destinations flexible, similar to paper checks: a single payment instrument that can be used to pay into people’s accounts, pay into company accounts, pay for bills, or pay to cash. The bitcoin address is the only representation of the keys that users will routinely see, because this is the part they need to share with the world.

He goes deeper into technical details as you continue reading. Don't know what exactly you want to know as your question was quite vague.

Very good book , and for free on git hub