試題1

以下關于數(shù)字證書的敘述中，錯誤的是（）
A、證書通常由CA安全認證中心發(fā)放
B、證書攜帶持有者的公開密鑰
C、證書的有效性可以通過驗證持有者的簽名
D、證書通常攜帶CA的公開密鑰

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試題2

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試題3

There are different ways to perform IP based DoS Attacks. The most common IP based DoS attack is that an attacker sends an extensive amount of connection establishment （1）(e.g. TCP SYN requests) to establish hanging connections with the controller or a DPS. Such a way, the attacker can consume the network resources which should be available for legitimate users. In other （2）, the attacker inserts a large amount of （3）packets to the data plane by spoofing all or part of the header fields with random values. These incoming packets will trigger table-misses and send lots of packet-in flow request messages to the network controller to saturate the controller resources. In some cases, an （4）who gains access to DPS can artificially generate lots of random packet-in flow request messages to saturate the control channel and the controller resources. Moreover, the lack of diversity among DPSs fuels fuels the fast propagation of such attacks.
Legacy mobile backhaul devices are inherently protected against the propagation of attacks due to complex and vendor specific equipment. Moreover, legacy backhaul devices do not require frequent communication with core control devices in a manner similar to DPSs communicating with the centralized controller. These features minimize both the impact and propagation of DoS attacks. Moreover, the legacy backhaul devices are controlled as a joint effort of multiple network element. For instance, a single Long Term Evilution（LTE）eNodeB  is connected up to 32 MMEs. Therefore, DoS/DDoS attack on a single core element will not terminate the entire operation of a backhaul device（5）the net work.

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試題4

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試題5

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試題6

67mod119的逆元是（）
A、52
B、67
C、16
D、19

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試題7

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試題8

甲不但懷疑乙發(fā)給他的被人篡改，而且懷疑乙的公鑰也是被人冒充的，為了消除甲的疑慮，甲和乙決定找一個雙方都信任的第三方來簽發(fā)數(shù)字證書，這個第三方為（）
A、國際電信聯(lián)盟電信標準分部（ITU-T）
B、國家安全局（NSA）
C、認證中心（CA）
D、國家標準化組織（ISO）

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試題9

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試題10

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