bitcoincashjs/docs/publickey.md

title	description
Public Key	A simple interface for handling private keys.

Public Key

Description

Represents a bitcoin public key and is needed to be able to receive bitcoin, as is usually represented as a bitcoin Address, see the official Bitcoin Wiki. A PublicKey in Bitcore is an immutable object and can be instantiated from a Point, string, PrivateKey, Buffer and a BN.

Instantiate a Public Key

Here is how to instantiate a public key:

var privateKey = new PrivateKey();

// from a private key
var publicKey = new PublicKey(privateKey);

// from a der hex encoded string
var publicKey2 = new PublicKey('02a1633cafcc01ebfb6d78e39f687a1f0995c62fc95f51ead10a02ee0be551b5dc');

Validating a Public Key

A public key point should be on the secp256k1 curve, instantiating a new PublicKey will validate this and will throw an error if it's invalid. To check that a public key is valid:

if (PublicKey.isValid('02a1633cafcc01ebfb6d78e39f687a1f0995c62fc95f51ead10a02ee0be551b5dc')){
  // valid public key
}

Note: It's important to note that there are two possible ways to represent public key, the standard is compressed and includes the x value and parity (as represented above in the documentation). There is also a longer version that is uncompressed which includes both x and y values, and using this can generate a different bitcoin address, so it's important to note this possibility, however it's discouraged to be used.