What is a digital certificate?

A Digital Certificate is an electronic file that is tied to a cryptographic key pair and authenticates the identity of a website, individual, organization, user, device or server. It is also known as a public key certificate or identity certificate. The certificate contains the subject, which is the identity piece, as well as a digital signature.

Why is a digital certificate necessary for a digital signature?

A digital certificate is necessary for a digital signature because it provides the public key that can be used to validate the private key that is associated with a digital signature. Digital certificates make it possible for digital signatures to be used as a way to authenticate digital information.

What is a digital signature or ID?

A digital signature or ID is more commonly known as a digital certificate. To digitally sign an Office document, you must have a current (not expired) digital certificate. Digital certificates are typically issued by a certificate authority (CA), which is a trusted third-party entity that issues digital certificates for use by other parties.