is the science of hiding information.Whereas.the goal of cryptography is tomake dataulueadable by a third party,the goal of steganography is to hide the data from athirdparty.In this article,I will discuss what steganography is;what purposes it serves,and will provide an example using available software.
There is?a large number of steganographic（）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?spreads?spectrum radio communication.With computers and networks,there are many other ways of hiding information,such as:
>Covert channels(e.g.,Loki and some distributed denial-of-service tools use the Internet Control（）Protocol,or ICMP,as the communications?channel?between the"bad guy"and a compromised system)
>Hidden text within web pages
>Hiding files in"plain?sight"(e.g.,what better place to"hide a file than with an important sounding name in the c:\winnt\system32 directory?）
>Null ciphers(e.g.,using the first letter of each word?to?from?a?hidden message in and otherwise innocuous text)
Steganography today,however,is significantly more（）than the examples above suggest,allowing a user to hide large amounts of infromation within image and audio files.these forms of steganography often are used in conjunction with cryprography so that the information is doubly protected;first it is encrypted and then hidden so that an adversary has to first find the information(an often difficult task in and of itself)and then?decrypt it.
The simplest approach to hiding data within an image flile is callde（）significant bit insertion in this method we can take the binary?representation of the hidden data and overwirit the bit of each byte within the cover image.if we are using 24-bit color the amount of change?well be mininmal and indiscerible to the human?eye.
问题1选项
A.Cryptography
B.Geography
C.Stenography
D.Steganography
问题2选项
A.methods
B.Softeare
C.Tools
D.Services
问题3选项
A.Member
B.management
C.message
D.Mail
问题4选项
A.powerful
B.Sophisticated
C.Advancde
D.easy
问题5选项
A.lesast
B.Most
C.Muchu
D.less
一台主机的IP地址为202.123.25.36，掩码为255.255.254.0。如果该主机需要在该网络进行直接广播，那么它应该使用的目的地址为（ ）
在计算机系统的日常维护工作中，应当注意硬盘工作时不能__(2)__。另外，需要防范病毒，而__(3)__是不会被病毒感觉的。
有 4 个 IP 地址：201.117.15.254、201.117.17.01、201.117.24.5 和 201.117.29.3，如果子网掩码为 255.255.248.0，则这 4 个地址分别属于3个子网；其中属于同一个子网的是（）
在异步通信中，每个字符包含1位起始位、7位数据位、1位奇偶位和1位终止位，每秒钟传送200个字符，采用4相位调制，则码元速率为（）。
在 Windows 中，运行（ ）命令得到下图所示结果。以下关于该结果的叙述中，错误的是（ ）。
Pinging 59.74.111.8 with 32 bytes of data:
Reply from 59.74.111.8: bytes=32 time=3ms TTL=60
Reply from 59.74.111.8: bytes=32 time=5ms TTL=60
Reply from 59.74.111.8: bytes=32 time=3ms TTL=60
Reply from 59.74.111.8: bytes=32 time=5ms TTL=60
Ping statistics for 59.74.111.8:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 3ms, Maximum = 5ms, Average = 4ms
在ISO OSF/RM参考模型中，七层协议中的__(1)__利用通信子网提供的服务实现两个用户进程之间端到端的通信。在这个模型中，如果A用户需要通过网络向B用户传送数据，则首先将数据送入应用层，在该层给它附加控制信息后送入表示层；在表示层对数据进行必要的变换并加头标后送入会话层；在会话层加头标送入传输层；在传输层将数据分解为__(本题)__后送至网络层；在网络层将数据封装成__(3)__后送至数据链路层；在数据链路层将数据加上头标和尾标封装成__(4)__后发送到物理层；在物理层数据以__(5)__形式发送到物理线路。B用户所在的系统接收到数据后，层层剥去控制信息，把原数据传送给B用户。
在OSI/RM中，解释应用数据语义的协议层是（）。
在TCP/IP协议栈中，ARP协议的作用是（）,RARP协议的作用是（请作答此空）。
在地址 http://www.dailynews.com.cn/channel/welcome.htm 中，www.dailynews.com.cn 表示（ ），welcome.htm 表示（请作答此空）。
在电子表格软件Excel中，假设A1单元格的值为15，若在A2单元格输入“=AND(15＜A1，A1＜100)”，则A2单元格显示的值为 （）
