问题 单项选择题

某公司网管员对核心数据的访问进行控制时,针对每个用户指明能够访问的资源,对于不在指定资源列表中的对象不允许访问。该访问控制策略属于______。

A.自主访问控制(DAC)
B.强制访问控制(MAC)
C.基于角色的访问控制(RBAC)
D.访问控制列表方式(ACL)

答案

参考答案:A

解析: 因实现的基本理念不同,访问控制可分为强制访问控制(MAC)和自主访问控制(DAC)两种。
强制访问控制中,系统独立于用户行为强制执行访问控制,用户不能改变他们的安全级别或对象的安全属性。这样的访问控制规则通常对数据和用户按照安全等级划分标签,访问控制机制通过比较安全标签来确定授予还是拒绝用户对资源的访问。自主访问控制机制允许对象的属主来制定针对该对象的保护策略。通常DAC通过授权列表(或访问控制列表)来限定哪些主体针对哪些客体可以执行什么操作。如此可以非常灵活地对策略进行调整。自主访问控制中,用户可以针对被保护对象制定自己的保护策略。每个主体拥有一个用户名并属于一个组或具有一个角色。每个客体都拥有一个限定主体对其访问权限的访问控制列表(ACL)。每次访问发生时都会基于访问控制列表检查用户标志以实现对其访问权限的控制。

判断题
单项选择题

Many foreigners who have not visited Britain call all the inhabitants English, for they are used to thinking of the British Isles as England. (1) , the British Isles contain a variety of peoples, and only the people of England call themselves English. The others (2) to themselves as Welsh, Scottish, or Irish, (3) the case may be; they are often slightly annoyed (4) being classified as "English".

Even in England there are many (5) in regional character and speech. The chief (6) is between southern England and northern England. South of a (7) going from Bristol to London, people speak the type of English usually learnt by foreign students, (8) there are local variations.

Further north regional speech is usually " (9) " than that of southern Britain. Northerners are (10) to claim that they work harder than Southerners, and are more (11) They are open-hearted and hospitable; foreigners often find that they make friends with them (12) Northerners generally have hearty (13) : the visitor to Lancashire or Yorkshire, for instance, may look forward to receiving generous (14) at meal times.

In accent and character the people of the Midlands (15) a gradual change from the southern to the northern type of Englishman.

In Scotland the sound (16) by the letter "R" is generally a p sound, and "R" is often pronounced in words in which it would be (17) in southern English. The Scots are said to be a serious, cautious, thrifty people, (18) inventive and somewhat mystical. All the Celtic peoples of Britain (the Welsh, the Irish, the Scots) are frequently (19) as being more "fiery" than the English. They are (20) a race that is quite distinct from the English. (289 words)

Notes: fiery 暴躁的,易怒的。

(3)()

A.as

B.which

C.for

D.so