what is a digital signature? 用英文答 急！！！答案参考《数字堡垒》！！1

In this article digital signature is used to mean a cryptographically based ... Many electronic signatures employ digital signature technology to ensure the ...

http://en.wikipedia.org/wiki/Digital_signature

A digital signature is an electronic rather than a written signature that can be used by someone to authenticate the identity of the sender of a message or of the signer of a document.

电子签名, 就是把签名扫描进电脑里,然后加入到文件上

It's a name printed ,not written by people.

Digital signature is a term with confusing reference. It is sometimes taken to be a 'subset' of electronic signatures.But some people use the term to describe something equivalent to an electronic signature.