COMPUTER NETWORKING

Detailed explanation-1: -Signature validity is determined by checking the authenticity of the signature’s digital ID certificate status and document integrity: Authenticity verification confirms that the signer’s certificate or its parent certificates exist in the validator’s list of trusted identities.

Detailed explanation-2: -A digital signature is an electronic form of a signature that can be used to authenticate the identity of the sender of a message or the signer of a document, and also ensure that the original content of the message or document that has been sent is unchanged.

Detailed explanation-3: -signer non-repudiation. An asymmetric key operation where the private key is used to digitally sign data and the public key is used to verify the signature. Digital signatures provide authenticity protection, integrity protection, and non-repudiation, but not confidentiality protection.