Tamper evidence is actually the only thing that cryptographic signatures provide. If either the "document" or signature is modified then verification fails. Cr

Tamper evidence is actually the only thing that cryptographic signatures provide. If either the "document" or signature is modified then verification fails. Cryptographic signatures don't provide evidence that someone looked at the "document" in transit. For that we use a separate sort of thing called encryption and prevent the problem entirely. The two things work together to provide the equivalent of a sealed envelope or securely folded paper document.