From this issue, this paper gives all [56,28,12] binary self-dual codes with an automorphism of order 7.Up to equivalence, there are 499 such codes.So this kind of codes are thoroughly solved.

• 针对此问题,本文给出了所有有阶为7的自同构的二元极大双偶编码[56,28,12],在等价关系下有499种这样的编码,从而使这类编码得到彻底解决。