Tell us about Digital Signature?

Question

Cryptography

Hello, I am currently working on the client-server part of the application, encrypting data packets, and in the module I came across "digital signatures", I had heard about this before, but did not delve into it very much. And now it's getting interesting. So far, I realized that the digital signature works a little differently than RSA encryption, that is, the sender encrypts with the private key, and anyone who has the public key can decrypt the message, but this guarantees that the key owner sent the message. But it's not entirely clear to me how it works in real life, in what situations it is used. Maybe there is someone who worked with this, tell us how you use signatures at home?

Answer 1

The hash of the message is encrypted and sent along with the message. By decrypting the hash and comparing it with the one you calculated yourself, you can verify the authenticity of the message.
The certificate that signed the message is usually itself signed by some trusted certificate authority. Or you are simply sure that the certificate definitely belongs to the organization or person.