论文标题
流密码的密钥依赖性安全性
Key-dependent Security of Stream Ciphers
论文作者
论文摘要
密码学的控制比以往任何时候都更加复发。由于当前的国际法规不适用于签署国，因此在加密系统中执行后门的概念已重生。本文介绍了一类特定的流密码后门。在80年代和90年代，在美国向西方国家施加的出口控制规则的背景下，该类别在80年代和90年代被行业广泛使用。我们在这里提出了一个新系统（称为BSEA-2），带有一个128位秘密键 - 这似乎是对BSEA-1的修改，这是\ cite {filiol_bsea1}中提出的系统。 BSEA-2用简单而教学的〜\ textemdash〜进行了说明，它也是为MSC密码分析课程〜\ textemdash〜而设计的，但有效的方式是密钥依赖性加密安全性的概念。目的是保持对加密的控制，这意味着一个国家/提供者可以向另一个国家/客户提供秘密密钥。通过这样的系统，更改关键类会导致降低加密安全性。
The control of the cryptography is more than ever a recurrent issue. As the current international regulation does not apply in the signatory countries, the concept of enforcing backdoors in encryption system is reborn with more strength. This paper deals with a particular class of stream cipher backdoors. This class, under a different form, has been widely used by the industry in the 80s and 90s in the context of the export control rules imposed by the US to the Western countries. We propose here a new system -- called BSEA-2, with a 128-bit secret key -- which is a seemingly minor modification of BSEA-1, a system proposed in \cite{filiol_bsea1}. BSEA-2 illustrates, in a simple and didactic~\textemdash~it has been also designed for a MSc cryptanalysis course~\textemdash~but efficient way the concept of key-dependent cryptographic security. The aim is to keep control on encryption means that a country/provider could provide to another country/client for which the secret key are also provided. With such systems, changing the key class results in downgrading the cryptographic security.
