To measure each gesture 's level of security , the researchers imported a concept from Information Theory called " differential entropy . " This metric quantified the " information content , " or " surprisingness , " of a gesture .
为了准确衡量每种手势的安全性，研究人员引入了信息论中的“微分熵”概念。这个概念能量化手势的“信息内容”或者说“多样性”。
surprisingness