The security level of the Shannon cipher system is traditionally measured by equivocation $ {{ 1}over { N}}H({mmb {Y}} vert Z)$, where $ {mmb {Y}} $ is a secret plaintext with length $N$ and $Z$ is its cryptogram. But, Merhav and Arikan have considered another security criterion, which is measured by the number of guesses needed for a wiretapper to uncover $ {mmb {Y}} $ from $Z$. Merhav has also considered the third security criterion, which measured by the probability of correct guess of a wiretapper. On the other hand, in the case of the traditional security criterion, Yamamoto has treated a coding problem for correlated source outputs $ {mmb {X}} $ and $ {mmb {Y}} $ such that only $ {mmb {X}} $ is secret against wiretappers and only $ {mmb {Y}} $ must be transmitted to a legitimate receiver. In this correspondence, coding theorems are proved for the case that Yamamoto''''s coding problem is applied to Merhav–Arikan''''s security criterion or Merhav''''s security criterion.
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机译：传统上，香农密码系统的安全级别是通过等价$ {{1}超过{N}} H（{mmb {Y}} vert Z）$来衡量的，其中$ {mmb {Y}} $是带有长度$ N $和$ Z $是其密码。但是，Merhav和Arikan考虑了另一种安全标准，该标准由窃听者从$ Z $中发现$ {mmb {Y}} $所需的猜测次数来衡量。 Merhav还考虑了第三安全标准，该标准通过对窃听者的正确猜测的概率来衡量。另一方面，在传统安全标准的情况下，Yamamoto处理了相关源输出$ {mmb {X}} $和$ {mmb {Y}} $的编码问题，使得仅$ {mmb {X} } $对窃听者是秘密的，只有$ {mmb {Y}} $必须被发送到合法接收者。在此对应关系中，针对将山本的编码问题应用于Merhav–Arikan的安全性准则或Merhav的安全性准则的情况，证明了编码定理。
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