A digital signature is made with?

A digital signature utilizes the signer's private key to encrypt a hash of the message, ensuring only the legitimate sender could have produced it and verifying message integrity upon decryption with the public key. This process is fundamental to asymmetric cryptography, where the private key is kept secret and used for signing, while the public key is shared and used for verification.

Signing with a public key is incorrect because the public key is widely distributed and cannot guarantee the authenticity or non-repudiation of the sender.

Symmetric key cryptography uses the same key for encryption and decryption, making it unsuitable for digital signatures where a distinct private key is needed for signing and a public key for verification.

Using a public key from a symmetric key pair is contradictory as symmetric cryptography does not involve public/private key pairs.