电子签名 :这种方式可以保证电子文件作者的确定性。它其实是一种特殊的技术给电子文件附加了密码 ,证实该文件确属该作者所发。它目前主要用于电子贸易领域。数字水印 :这种方式可以保证电子文件本身的原始性。它是利用某种技术把作者的标志 ,如印鉴、花纹等隐藏于电子文件中 Electronic Signature: This approach ensures the certainty of the author of the electronic document. It is actually a special technique that appends a password to an electronic document, confirming that the document was indeed made by the author. It is currently mainly used in the field of electronic commerce. Digital Watermarking: This method can ensure the original nature of electronic documents. It is the use of some kind of technology to the author’s logo, such as seals, patterns hidden in electronic documents