Asymmetric key cryptography is a widely used encryption technique in modern cryptography. It has a lot of applications other than encryption. It is also commonly used in several elements of blockchain, so we will cover this cryptography technique in depth, along with its primitives.
Symmetric key cryptography uses a shared key for both encryption and decryption. The biggest problem with this is that the shared key needs to be exchanged between participants over a secure channel, which can be quite hard to achieve. It also defeats the objective of encryption if we have a secure channel for communication in the first place. This is where asymmetric cryptography comes in. It uses a pair of keys called a public/private pair. The public key is constructed from the private key and can be freely broadcasted to other users.