equal
deleted
inserted
replaced
14 \end{center} |
14 \end{center} |
15 |
15 |
16 where $P$ is a principal and $F$ a formula. Give two inference rules |
16 where $P$ is a principal and $F$ a formula. Give two inference rules |
17 of access-control logic involving $\textit{says}$. |
17 of access-control logic involving $\textit{says}$. |
18 |
18 |
19 \item |
19 \item (Removed) Was already used in HW 5 |
20 The informal meaning of the formula $P\;\textit{controls}\;F$ is `$P$ is entitled |
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21 to do $F$'. Give a definition for this formula in terms of $\textit{says}$. |
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22 |
20 |
23 \item |
21 \item |
24 Assume an access control logic with security levels, say top secret ({\it TS}), |
22 Assume an access control logic with security levels, say top secret ({\it TS}), |
25 secret ({\it S}) and public ({\it P}), with |
23 secret ({\it S}) and public ({\it P}), with |
26 \begin{center} |
24 \begin{center} |