我刚找到这支铅笔和纸密码“Felix”,我想知道它有多安全?
编辑
来自http://web.archive.org/web/20110825142054/http://topcat.hypermart.net/papers/felix.txt
费利克斯是一种铅笔和纸张密码。简介费利克斯是一个pencil-and-paper cipher' offering relatively good security for causal use. Unlike modern encoding schemes that require, at a minimum, a co