ECDSA is a cryptographic alghorithm.
What makes it interesting?
ECDSA is used to authenticate the origin of a message, like a digital signature
How does it work?
Well, it uses math, and it does it in a way to make it impossible to know the private key of a signer, but also pretty easy to verify that a signature was generated from a public key
What are public and private key?
The keys are numbers, very special numbers, the private key must remain secret, so that the public can be shared and signatures can be verified
What if someone finds my private key?
What if someone finds your email password? he can pretend to be you!
ECDSA is useful to send messages and verify the signatures, it is very powerful, but it needs to be used wisely