水印的英文：watermark

n.(纸张上的)水印

复数： watermarks

例句：

Research on Authentication Watermark Technique and Its Application in Electronic Signature System

认证水印技术及在电子签章系统的应用研究

A new approach of digital watermark based on information optics is presented.

提出一种新的基于信息光学的数字水印方法。