Can symmetric cryptography be used for providing digital signatures?

Question

I was wondering what the main reason was for symmetric keys not being used in this context?

Answer 1

With a symmetric key, anyone who could check the signature could also forge a signature. For most of the use cases of digital signatures, we want untrusted parties to be able to verify the signature. That requires that the key you use to check that a signature is correct be insufficient to generate a valid signature, and that requires asymmetric cryptography by definition.