Their campaign has led some scientists to give up GM research and others to call for the British government to carry out trials at secure or secret sites.

VOA: standard.2009.10.21

So in general, both of these are examples of what we call secret key crypto.

所以通常，这两个都是,加密技术的例子。

哈佛公开课 - 计算机科学课程节选