Study on Highly Secure and Efficient Symmetric Key Cryptosyste

我们已经完成了以下主要结果。我们提出了一个可移动的块密码的构造，其中的块长度短或大于2N位，来自一个n位可移动的块密码。我们建议为1型通用羽毛结构构建渗透层，因为它们具有良好的扩散特性。我们展示了EAX-Prime允许各种有效的攻击。如果输入数据被称为干净的文本，我们也可以确保它的安全性，它的块长度将永远比严格的块密码长。我们展示了GCM的原始安全证明，它包含了一个闪光。我们还展示了闪光是固定的，因此GCM可以保持其可提供的安全性。

We obtain the following main results.・We propose a construction of a tweakable block cipher whose block length is shorter or longer than 2n bits, from an n-bit tweakable block cipher.・ We propose constructions of a permutation layer for Type-1 generalized Feistel structures so that they have a good diffusion property.・We show that EAX-prime allows various efficient attacks. We also prove its security if the input data called a cleartext is always longer than the block length of theunderlying block cipher.・We show that the original security proof of GCM contains a flaw. We also show that the flaw can be fixed and therefore GCM maintains its provable security.