Asymmetric encryption uses tow separate but mathematically connected keys known as "Private and Public" keys.

Together, they are called a "public and private pair" or just "key pair".

One of the keys, the public key, is available for anyone to uses. The other key is known as the private key.

Data encrypted with the public key can ONLY be encrypted with the private key. This is why Asymmetric encryption is also known as "public-key cryptography."

How Asymmetric Encryption Works in Crypto

Asymmetric encryption was first used to encrypt and decrypt messages. But cryptocurrencies now use this technology in a slightly different way.

In  crypto, the sender uses his private key to encrypt a special message amd the recipient uses the sender’s public key to decrypt it. 

If you wanted to send confidential  messages,  it would be a bad idea since anyone with your public key, which by definition, is public, would be able to decrypt your message and read it.

But in cryptocurrencies, all transactions are made public so it doesn't need to keep the data private or confidential. 

It uses Asymmetric encryption for a totally different purpose. Amd it's pretty clever.

It uses Asymmetric encryption for authentication — to prove you are who you say you are.

More specifically, when you want to send some bitcoins to another person, it's used to prove that YOU are the actual owner of the crypto assets that you wish to send.

If you encrypt ("lock") something with your private key, anyone can decrypt it ("unlock") with your public key.

This serves as a proof that you are the original sender of the message because you are the ONLY one who would be able to encrypt the message (because you have the corresponding private key)

And since now that you are the identity (true owner of crypto assets you wish to send) has been authnticated, you are now authorised to send crypto assets.