The block cipher is an important means to provide data confidentiality in reality, and the S-box is an essential part in most of modern block cipher designs. In 1973, Feistel used a key selected S-box mechanism in his early block cipher designs, whose idea is to let each S-box have two different states and use a key bit to select which of the two states is to be used in an encryption or decryption operation. However, this key selected S-box mechanism has not got much attention in modern block cipher design with the DES block cipher published in 1977. In this paper, we revisit Feistel’s key selected S-box mechanism, give a generalised version of Feistel’s key selected S-box mechanism, compare it with existing close notions, and design the LBC example cipher to demonstrate that the generalised key selected S-box mechanism can be advantageous over the ordinary S-box mechanism in modern block cipher design for improving security and/or performance without intensifying computational effort and space in some application environments.

中文翻译：

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S-Box关键选择机制及其在现代分组密码设计中的研究

分组密码是现实中提供数据机密性的重要手段，而S-box是大多数现代分组密码设计中必不可少的部分。1973年，Feistel在他的早期分组密码设计中使用了密钥选择的S-box机制，其思想是让每个S-box具有两个不同的状态，并使用一个密钥位选择在加密中使用这两个状态中的哪一个。加密或解密操作。但是，这种密钥选择的S-box机制在1977年发布的DES分组密码技术中并未受到现代分组密码设计的广泛关注。在本文中，我们将重新审视Feistel的密钥选择的S-box机制，给出Feistel密钥选择的广义版本。 S-box机制，将其与现有的封闭式概念进行比较，