试题1

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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试题2

（1）is the science of hiding information. Whereas the goal of cryptography is to make data unreadable by a third party. the goal of steganography is to hide the data from a third party. In this article, I will discuss what steganography is, what purposes it serves, and will provide an example using available software.
There are a large number of steganographic （2）that most of us are familiar with (especially if you watch a lot of spy movies), ranging from invisible ink and microdots to secreting a hidden message in the second letter of each word of a large body of text and spread spectrum radio communication. With computers and networks, there are many other ways of hiding informations, such as:
Covert channels (c,g, Loki and some distributed denial-of-service tools use the Internet Control （3）Protocol, or ICMP, as the communication channel between the “bad guy”and a compromicyed system)
Hidden text within Web pages
Hiding files in “plain sight”(c,g. what better place to “hide”a file than with an important sounding name in the c:\winnt system32 directory)
Null ciphers(c,g, using the first letter of each word to form a hidden message in an otherwise innocuous text)
steganography today, however, is significantly more （4）than the example about suggest, allowing a user to hide large amounts of information within image and audio. These forms of steganography often are used in conjunction with cryptography so the information is double protected; first it is encrypted and then hidden so that an advertisement first. find the information ( an often difficult task in and of itself) and the decrypted it.
The simplest approach to hiding data within an image file is called （5）signature insertion. In this method, we can take the binary representation of the hidden data and the bit of each byte within the covert image. If we are using 24-bit color the amount and will be minimum and indiscriminate to the human eye.
（1）A、Cryptography
B、Geography
C、Stenography
D、Steganography
（2）A、methods
B、software
C、tools
D、services
（3）A、Member
B、Management
C、Message
D、Mail
（4）A、powerful
B、sophistication
C、advanced
D、easy
（5）A、least
B、most
C、much
D、less

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试题3

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试题4

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试题5

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试题6

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试题7

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试题8

有一种原则是对信息进行均衡、全面的防护，提高整个系统的安全性能，该原则称为（）
A、动态化原则
B、木桶原则
C、等级性原则
D、整体原则

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试题9

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试题10

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