一种2—安全码的组合构造

Combinatorial Construction of a 2_Secure Code

完全安全码是不存在的,这已经从理论上得到证明。任何安全码在某一种情况下,对叛逆者的追踪必定失败。这里用分组设计的方法构造出一种2—安全码。每一个码字对应一个n阶方阵。嵌入到数字产品中的码字长度比相应的矩阵长度要小。当发现盗版产品时,不是通过盗版码字,而是通过盗版码字相应的矩阵确定出共谋者。追踪算法追踪效率很高,而且它要么运行失败,要么输出一个共谋者,也就是说,该追踪算法的一个非常重要的性质是不会冤枉无辜用户。

Completely secure code does not exit, this argument has been theoretically proved. Any secure code is bound to fail in tracing traitors in some case. In this paper, a combinatorial construction of a 2_secure code by block design is presented. Every code word corresponds to a square matrix of order n. The length of the code word embedded in digital product is shorter than that of the corresponding matrix. When a piratical product is found, the colluders are traced not by the piratical code word but by the corresponding matrix. The tracing algorithm has efficient traceability, and it either fails or outputs a colluder ,that is to say, an important property of the algorithm is that no innocent users would be wronged.