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<?xml version="1.0" encoding="utf-8"?>
<search>
<entry>
<title>发布博文出错fatal、OpenSSL SSL_connect|hexo</title>
<link href="/2022/05/09/SSL/"/>
<url>/2022/05/09/SSL/</url>
<content type="html"><![CDATA[<p>问题描述：fatal: unable to access 'https://github.com/xxx': OpenSSLSSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443[duplicate]<br />解决措施：<code>git config --global --unset-all remote.origin.proxy</code><br /><ahref="https://stackoverflow.com/questions/49345357/fatal-unable-to-access-https-github-com-xxx-openssl-ssl-connect-ssl-error">解决措施的参考来源</a></p>]]></content>
</entry>
<entry>
<title>给图片加水印的程序|python</title>
<link href="/2022/05/06/watermarker/"/>
<url>/2022/05/06/watermarker/</url>
<content type="html"><![CDATA[<p>问题来源：在闲鱼卖东西的时候为了防盗要给照片加水印、实习时身份证照片要打水印......找不到简单好用的手机app1. <code>pip install opencv-python==3.4.9.31</code><br />> 如果不带上版本号，可能会遇到长时间停留在 building wheel foropencv-python的情况，带上版本号并且是旧版本号可以很快安装好 2.测试是否成功安装opencv-python<br />运行以下程序，若正确输出版本号则成功安装opencv-python <span id="more"></span><figure class="highlight stylus"><table><tr><td class="gutter"><div class="code-wrapper"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></div></td><td class="code"><pre><code class="hljs stylus">import cv2<br><span class="hljs-function"><span class="hljs-title">print</span><span class="hljs-params">(cv2.__version__)</span></span><br></code></pre></td></tr></table></figure> 3. <code>pipe3 install Pillow==4.0.0</code><br />> 跟上版本号很重要，不然会出错，原因是我的macOS没有升级到最新版本。一开始一直出错，最终找到这个解决方法，<ahref="https://blog.51cto.com/u_13567403/3051637">答案来源</a> 4.<code>cd /Users/flower/PycharmProjects</code><br /><code>git clone https://github.com/2Dou/watermarker.git</code><br />watermarker文件夹中font文件夹下的青鸟华光琥珀改为bird，同时marker.py中的青鸟华光琥珀也都改为bird，改成什么名字不重要，只要都改成一样的并且都是英文就行<br />5. 把要添加水印的照片放到watermark下的input文件夹内<br /><code>cd /Users/flower/PycharmProjects/watermark</code><br /><code>python marker.py -f ./input/a.jpg -m yingcuiwen花花</code><br />在watermark下的output文件夹内查看添加好水印的图片<br />6. 批量处理<br />运行<code>python marker.py -f ./input -m yingcuiwen花花</code><br />> 一开始出错:cannot identify image file ‘pikachu/.DS_Store’，参考 <ahref="https://its304.com/article/weixin_38411989/109311229">此篇博文</a><br /><code>cd watermarker</code><br /><code>find ./ -name ".DS_Store"</code><br /><code>find ./ -name ".DS_Store" -delete</code></p><h3 id="在此过程中学会的其他知识">在此过程中学会的其他知识:</h3><h4 id="安装opencv">安装OpenCV</h4><ol type="1"><li><a href="https://opencv.org/releases/">下载OpenCV</a><br /></li><li>安装cmake：<ahref="https://blog.csdn.net/fanyun_01/article/details/114237851">教程</a><br /></li><li><code>cd opencv-4.5</code><br /><code>mkdir build</code><br /><code>cd build</code> <code>cmake -G "Unix Makefiles" ..</code><br /><code>make</code><br /><code>sudo make install</code></li></ol>]]></content>
<categories>
<category>功能与技巧</category>
</categories>
</entry>
<entry>
<title>开发基于SSM的管理系统-1安装所需软件|java</title>
<link href="/2022/05/05/ssm/"/>
<url>/2022/05/05/ssm/</url>
<content type="html"><![CDATA[<p>macOS High Sierra 10.13.4</p><h1 id="tomcat">tomcat</h1><ol type="1"><li><p>从<ahref="https://tomcat.apache.org">官网</a>下载tomcat，选择tar.gz的安装包（在core一列中）。下载后解压，将解压出来的文件夹重新命名为“Tomcat”，拖入《Library》文件夹。（注意：不要拖入/Users/flower/Library，而是拖入/Library）<br /><span id="more"></span></p></li><li><p>Terminal<br /><code>cd /Library/Tomcat/bin</code><br /></p></li><li><p>授权bin目录下的所有操作<br /><code>sudo chmod 755 *.sh</code><br />输入密码，回车<br />>chmod改变文件的存取模式：三个数字分别表示[User][Group][Others]，读4写2执行1。参数-R表示递归改变当前目录下的所有目录和文件的权限。eg.<code>chmod -R 777 foldername</code></p></li><li><p><code>sudo sh ./startup.sh</code><br /></p></li><li><p>浏览器输入http://localhost:8080/<br /></p></li><li><p>关闭Tomcat<br /><code>sh ./shutdown.sh</code><br />回车</p></li><li><p><code>cd /Library/Tomcat/bin</code><br /><code>sh ./version.sh</code> # Eclipse<br /></p></li><li><p>发现原本安装的Eclipse不是For JavaEE，表现为没有新建Dynamic WebProject的选项，所以先重新安装Eclipse。</p></li><li><p>下载时点击Select Another Mirror 大连东软信息学院。Downloadeclipse-inst-jre-mac64.dmg</p></li><li><p>双击安装程序，选择Eclipse IDE for Enterprise Java and WebDevelopers。<br />> Java11+VM/Library/Java/JavaVirtualMachines/jdk-12.0.1.jdk/Contents/Home<br />Installation Folder Users/flower/eclipse/jee-2021-122<br />WorkPlace /Users/flower/eclipse-workspace<br /># MySQL<br /></p></li><li><p>下载MySQL安装包，注意和macOS版本匹配，我的macOS没有更新到最新的版本，所以不能下载最新版本的MySQL安装包，一开始下载错了，重新下载了8.0.22版本的。</p></li><li><p>查看MySQL路径<br /><code>cd /Usr/local/mysql</code><br /><code>ls</code><br /></p></li><li><p>添加MySQL的路径<br /><code>cd ~</code><br /><code>touch .bash_profile</code><br /><code>open -e .bash_profile</code><br /></p></li><li><p>添加一行export PATH="/usr/local/mysql/bin:$PATH"<br /></p></li><li><p>保存，然后查看有没有保存成功<br /><code>source ~/.bash_profile</code><br /><code>echo $PATH</code><br /></p></li><li><p>验证MySQL的运行<br />重新打开终端<code>mysql -u root -p</code>输入密码</p></li><li><p>可以下载MySQLWorkbench数据库管理工具</p></li></ol>]]></content>
<categories>
<category>功能与技巧</category>
</categories>
</entry>
<entry>
<title>Dessert</title>
<link href="/2020/06/21/Dessert/"/>
<url>/2020/06/21/Dessert/</url>
<content type="html"><![CDATA[<ul><li><p>Linux内核移植是什么意思？</p><p>Linux内核代码包含大部分硬件平台的驱动程序，用户可以自己定制内核包含哪些设备的驱动程序，就像开关一样，可以打开/关闭一些编译选项来支持不同的硬件平台。</p><p>内核移植就是根据自己的硬件平台重新编译内核，使之可以运行。如果缺少相应的硬件驱动程序或其他内核模块，可以自己进行开发，加入到内核中一起编译最终实现对硬件的支持。</p></li><li><p>什么是硬件驱动程序？</p><p>驱动程序，英文名为“DeviceDriver”，全称为“设备驱动程序”，是一种可以使计算机和设备通信的特殊程序。</p><p>首先其作用是将硬件本身的功能告诉操作系统，接下来的主要功能就是完成硬件设备电子信号与操作系统及软件的高级编程语言之间的互相翻译。当操作系统需要使用某个硬件时，比如：让声卡播放音乐，它会先发送相应指令到声卡驱动程序，声卡驱动程序接收到后，马上将其翻译成声卡才能听懂的电子信号命令，从而让声卡播放音乐。</p><p>计算机有I/O模块，就要有对应的程序。（冯·诺伊曼结构：CPU[控制器&运算器]、存储器、输入输出设备）</p></li><li><p>...</p></li></ul>]]></content>
<categories>
<category>知识与理解</category>
</categories>
</entry>
<entry>
<title>A斯塔克尔伯格模型</title>
<link href="/2019/12/17/stackel/"/>
<url>/2019/12/17/stackel/</url>
<content type="html"><![CDATA[<p>在有些市场，竞争厂商之间的地位不是对称的，市场地位的不对称引起了决策次序的不对称，通常，小企业先观察到大企业的行为，再决定自己的对策。主导企业知道跟随企业一定会对它的产量作出反应，因而当它在确定产量时，把跟随企业的反应也考虑进去了。</p><p>产量的决策依据以下次序：领导性厂商决定一个产量，然后跟随厂商可以观察这个产量，并根据领导性厂商的产量来决定他自己的产量。</p><p>领导性厂商所决定的产量将是一个以跟随厂商的反应函数为约束的利润最大化产量。在斯塔克尔伯格模型中，领导性厂商的决策不再需要自己的反应函数。</p><p><br /></p><span id="more"></span><p><strong>一、模型分析</strong></p><p>设市场需求函数为 <spanclass="math inline">\(D=D(p_1+p_2)=a-b(p_1+p_2)\)</span>，其中 <spanclass="math inline">\(p_1\)</span> 和 <spanclass="math inline">\(p_2\)</span> 分别是两个厂商的产量。</p><p>假设两厂商的成本函数相同，都为 <spanclass="math inline">\(C=c_0p\)</span></p><p><strong>步骤1：</strong>首先考虑在给定厂商的1的计划产量下，厂商2寻求使自己利润最大化的最有产量<spanclass="math inline">\(p_2\)</span>，即：</p><p><span class="math inline">\(maxp_2[a-b(p_1+p_2)]-cp_2\)</span>，</p><p>显然 <span class="math inline">\(p_2=g(p_1)\)</span></p><p><strong>步骤2：</strong>接下来，求解 <spanclass="math inline">\(maxp_1=[a-b（p_1+p_2）]-cp_1\)</span></p><p>得到 <span class="math inline">\(p_1\)</span> ，代入 <spanclass="math inline">\(p_2=g(p_1)\)</span> 得到 <spanclass="math inline">\(p_2\)</span></p><p>于是得到斯塔克尔伯格均衡时的 <spanclass="math inline">\((p_1,p_2)\)</span></p><p><br /></p><p><strong>二、应用实例</strong></p><p>设市场需求函数为 <spanclass="math inline">\(D=61.2-10\times(p_1+p_2)\)</span>，两厂商的成本函数都为 <spanclass="math inline">\(C=1.2p\)</span>，求斯塔克尔伯格均衡时两厂商的产量。（厂商1为领导者，厂商2为跟随者）</p><p>解：步骤1，求解如下优化模型：</p><p><spanclass="math inline">\(maxp_2[61.2-10\times(p_1+p_2)]-1.2p_2\)</span></p><p>得到 <spanclass="math inline">\(p_2=\frac{61.2-10p_1}{11.2}\)</span></p><p>步骤2，求解下列优化模型：</p><p><span class="math inline">\(maxp_1[61.2-10(p_1+p_2)]-1.2p_1,s.t.p_2=\frac{61.2-10p_1}{11.2}\)</span></p><p>得到结果 <spanclass="math inline">\(p_1\approx3,p_2\approx1.5\)</span></p><p><strong>matlab代码：</strong></p><figure class="highlight matlab"><table><tr><td class="gutter"><div class="code-wrapper"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></div></td><td class="code"><pre><code class="hljs matlab">clear<br>clc<br><br>syms x z;<br>y2=-x*(<span class="hljs-number">61.2</span><span class="hljs-number">-10</span>*(x+z))+<span class="hljs-number">1.2</span>*x;<br>eq=diff(y2,x);<br>p2=solve(eq,x);<br><br>y1=-z*(<span class="hljs-number">61.2</span><span class="hljs-number">-10</span>*(z+p2))+<span class="hljs-number">1.2</span>*z;<br>vdpf = matlabFunction([y1],<span class="hljs-string">'Vars'</span>,{z}); <br><span class="hljs-comment">%将符号表达式转化为函数句柄!!!</span><br>[p1,fval1]=fminsearch(vdpf,<span class="hljs-number">0</span>);<br>p2=subs(p2,<span class="hljs-string">'z'</span>,p1);<br>[p1,p2]<br></code></pre></td></tr></table></figure><p><strong>运行结果：</strong></p><p><imgsrc="https://tva1.sinaimg.cn/large/006tNbRwly1g9zx99mv3jj316q0u0qaw.jpg" /></p>]]></content>
<categories>
<category>知识与理解</category>
</categories>
<tags>
<tag>博弈论</tag>
</tags>
</entry>
<entry>
<title>disscussOFtheNEWone</title>
<link href="/2019/12/03/discussOFtheNew/"/>
<url>/2019/12/03/discussOFtheNew/</url>
<content type="html"><![CDATA[<p><strong>【20191203 星期二下午16:00】</strong></p><p><strong>中心思想：</strong>分布式的矿工决策</p><p><strong>问题来源：</strong>比特币系统中有许多个矿池，还有很多矿工。每个矿工进行盲目的个人决策，决定加入哪个矿池来挖矿。如果有人的收益高，有人的收益低，低收益的人就有动机去寻找比原本的选择更好的策略，如果找到了，那么收益高低情况会发生改变（这就是说，在之前的情况中占优势的矿工，虽然他们自己不想改变，但是别人的改变使得他们的收益情况也跟着改变了）。那么现在我们就考虑存在一个均衡点，大家都不会想要偏离，即使有人移动了，对应也会有其他人移动，算力比例仍旧不变。</p><p>显然，所有矿工都去一个矿池不是均衡点，那么每个矿池多少算力才达到均衡呢？</p><p><strong>目标：</strong>让矿工的单位算力平均收益最大</p><p><strong>前提假设：</strong>1、每个矿工都知道各个矿池的情况。</p><p>2、简化地认为每个矿工都是一样的。因为如果有一个矿工拥有更多的算力，在计算时可以将他的算力拆分，看作是两个矿工。</p><p><strong>需要完成的任务：</strong></p><p>1、判断是否有均衡点</p><p>2、找到一个均衡点并分析均衡点的性质（当然，可能会有多个均衡点，但是找出一个就可以）。找出均衡点就是找出均衡情况下每个矿池所占算力的比例。</p><p>3、设计一个算法，帮助矿工进行决策</p><p><strong>说明与提醒：</strong>如果能证明是NP问题，更好。</p><p>需要注意的是，可能无法简单地使用优化理论来做，也就是说，这个问题不是给出限制条件来进行求解，而是认为尽管存在均衡点，但是矿工们无法统一来达到均衡，故而需要我们的算法帮助矿工们朝着均衡点前进（矿工相信我们的算法，根据我们的算法进行决策）。</p><p>算法的设计需要巧妙一些，可能是一个多轮决策的过程，比方说初始大家都选择A矿池，然后共享一些全局信息，然后比如说随机可能30%的矿工算力让他们去B矿池，用一个迭代的过程来最终找到一个均衡。这个均衡可能是完全和分析出来的均衡比例一致，也可以设定一个允许的偏差，认为在实践中有一个小的差距也是可以的。</p><p><strong>hint：</strong>矿池自带算力，本身就有初始的算力差异，比方说矿池用一些手段吸引矿工加入他的矿池挖矿，矿工为何偏离一个矿池，矿池的差异在哪里（算力大小，交易费，幸运值，矿池设定的难度值······），不同策略（选择不同矿池）的差异在哪里，收益取决于什么，收益函数的表达······</p>]]></content>
<categories>
<category>论文与线索</category>
</categories>
</entry>
<entry>
<title>09混合策略在网球比赛中的应用</title>
<link href="/2019/12/02/nineMixStrategy/"/>
<url>/2019/12/02/nineMixStrategy/</url>
<content type="html"><![CDATA[<p>这篇blog主要整理了耶鲁大学博弈论公开课「第9课混合策略」的笔记。</p><hr /><p>混合策略就是在纯策略上的一个概率分布。</p><p>混合策略的预期收益是该混合策略中每个纯策略预期收益的加权平均数。</p><p><span class="math inline">\(\color{blue}{e.g.}\)</span><strong>性别之战</strong></p><table><colgroup><col style="width: 8%" /><col style="width: 27%" /><col style="width: 27%" /><col style="width: 27%" /><col style="width: 8%" /></colgroup><thead><tr class="header"><th style="text-align: center;"></th><th style="text-align: center;"></th><th style="text-align: center;">2</th><th style="text-align: center;"></th><th></th></tr></thead><tbody><tr class="odd"><td style="text-align: center;"></td><td style="text-align: center;"></td><td style="text-align: center;">a</td><td style="text-align: center;">b</td><td></td></tr><tr class="even"><td style="text-align: center;">1</td><td style="text-align: center;">A</td><td style="text-align: center;"><spanclass="math inline">\(\color{red}{2},1\)</span></td><td style="text-align: center;"><spanclass="math inline">\(\color{red}{0},0\)</span></td><td><span class="math inline">\(\frac{1}{5}\)</span></td></tr><tr class="odd"><td style="text-align: center;"></td><td style="text-align: center;">B</td><td style="text-align: center;"><spanclass="math inline">\(\color{green}{0},0\)</span></td><td style="text-align: center;"><spanclass="math inline">\(\color{green}{1},2\)</span></td><td><span class="math inline">\(\frac{4}{5}\)</span></td></tr><tr class="even"><td style="text-align: center;"></td><td style="text-align: center;"></td><td style="text-align: center;"><spanclass="math inline">\(\frac{1}{2}\)</span></td><td style="text-align: center;"><spanclass="math inline">\(\frac{1}{2}\)</span></td><td></td></tr></tbody></table><p>已知<span class="math inline">\(p=(\frac{1}{5},\frac{4}{5})\)</span>， <span class="math inline">\(q=(\frac{1}{2},\frac{1}{2})\)</span> ，求<span class="math inline">\(p=(\frac{1}{5},\frac{4}{5})\)</span>的预期收益是什么？</p><p>（1）<spanclass="math inline">\(EU_{1}(A,q)=\color{red}{2}\times\frac{1}{2}+\color{red}{0}\times\frac{1}{2}=1\)</span></p><p><spanclass="math inline">\(EU_{1}(B,q)=\color{green}{0}\times\frac{1}{2}+\color{green}{1}\times\frac{1}{2}=\frac{1}{2}\)</span></p><span id="more"></span><p>（2）<spanclass="math inline">\(EU_{2}(p,q)=\frac{1}{5}EU_{1}(A,q)+\frac{4}{5}EU_{1}(B,q)\)</span></p><p><spanclass="math inline">\(=\frac{1}{5}\times1+\frac{4}{5}\times\frac{1}{2}\)</span></p><p><span class="math inline">\(=\frac{3}{5}\)</span></p><p><span class="math inline">\(\frac{1}{2}<\frac{3}{5}<1\)</span>，一般选择混合策略的预期收益介于混合策略所包含的纯策略的预期收益之间。</p><p><strong>Lesson</strong>：如果一个混合策略是BR，那么混合策略中的每个纯策略必须也是BR，也就是说他们的收益必须相同。</p><p><br /></p><p><span class="math inline">\(\color{blue}{e.g.}\)</span> <strong>网球Venus vs. Serena Williams</strong></p><p>Serena在网前，球在Venus那半场，V接到球后要选择往S的左边还是右边击打。</p><p>Serena选择l代表作为回应，向左倾；选择r代表作为回应向右倾</p><table><thead><tr class="header"><th style="text-align: center;"></th><th style="text-align: center;"></th><th style="text-align: center;">S</th><th style="text-align: center;"></th><th style="text-align: center;"></th></tr></thead><tbody><tr class="odd"><td style="text-align: center;"></td><td style="text-align: center;"></td><td style="text-align: center;">l</td><td style="text-align: center;">r</td><td style="text-align: center;"></td></tr><tr class="even"><td style="text-align: center;">V</td><td style="text-align: center;">L</td><td style="text-align: center;"><spanclass="math inline">\(50,50\)</span></td><td style="text-align: center;"><spanclass="math inline">\(80,20\)</span></td><td style="text-align: center;"><spanclass="math inline">\(p\)</span></td></tr><tr class="odd"><td style="text-align: center;"></td><td style="text-align: center;">R</td><td style="text-align: center;"><spanclass="math inline">\(90,10\)</span></td><td style="text-align: center;"><spanclass="math inline">\(20,80\)</span></td><td style="text-align: center;"><spanclass="math inline">\(1-p\)</span></td></tr><tr class="even"><td style="text-align: center;"></td><td style="text-align: center;"></td><td style="text-align: center;"><spanclass="math inline">\(q\)</span></td><td style="text-align: center;"><spanclass="math inline">\(1-q\)</span></td><td style="text-align: center;"></td></tr></tbody></table><p>这里没有纯策略纳什均衡。</p><p>下面寻找混合策略纳什均衡——</p><p>（1）寻找NE时S的混合策略，关键在于用S的混合策略<spanclass="math inline">\((q,1-q)\)</span>分析V的收益。</p><p>V的收益是：</p><p><span class="math inline">\(L\to 50q+80(1-q)\)</span></p><p><span class="math inline">\(R\to 90q+20(1-q)\)</span></p><p>假设V也同样混合她的策略，现在V处于NE中，那么无论<spanclass="math inline">\(p\)</span>多大，V采取的一定也是BR。V采取的BR包含了有时向左有时向右的情况，那么这必须满足选左还是选右本身也是BR。这就是说，选左和选右的混合是BR，那么选左选右单独也是BR。选左和选右的收益必须是相等的。</p><p>令 <span class="math inline">\(50q+80(1-q)=90q+20(1-q)\)</span></p><p>解得 <span class="math inline">\(q=\frac{3}{5}\)</span></p><p>（2）寻找NE时V的混合策略，关键在于用V的混合策略<spanclass="math inline">\((p,1-p)\)</span>分析S的收益</p><p><span class="math inline">\(l\to50p+10(1-p)\)</span></p><p><span class="math inline">\(r\to20p+80(1-p)\)</span></p><p>令 <span class="math inline">\(50p+10(1-p)=20p+80(1-p)\)</span></p><p>解得 <span class="math inline">\(p=\frac{7}{10}\)</span></p><p>（3）综上，<spanclass="math inline">\(NE=[(\frac{7}{10},\frac{3}{10}),(\frac{3}{5},\frac{2}{5})]\)</span></p><p><br /></p><p>假设我是V的教练，我发现S防左的概率>0.6，那么我会建议V朝右打（<em>总是</em>打右）；相反，如果我发现S防左的概率<0.6，那么我会建议V<em>始终</em>朝左打。</p><p>注意上面一段中斜体的两个词“总是”和“始终”，因为如果S采用的策略不是<span class="math inline">\((\frac{3}{5},\frac{2}{5})\)</span>的混合策略，那么V的BR就是纯策略；且如果V采用的策略不是 <spanclass="math inline">\((\frac{7}{10},\frac{3}{10})\)</span>的混合策略，那么S的BR就是纯策略。</p><p><br /></p><p><strong>改变收益矩阵</strong></p><table><thead><tr class="header"><th style="text-align: center;"></th><th style="text-align: center;"></th><th style="text-align: center;">S</th><th style="text-align: center;"></th><th style="text-align: center;"></th></tr></thead><tbody><tr class="odd"><td style="text-align: center;"></td><td style="text-align: center;"></td><td style="text-align: center;">l</td><td style="text-align: center;">r</td><td style="text-align: center;"></td></tr><tr class="even"><td style="text-align: center;">V</td><td style="text-align: center;">L</td><td style="text-align: center;"><spanclass="math inline">\(30,70\)</span></td><td style="text-align: center;"><spanclass="math inline">\(80,20\)</span></td><td style="text-align: center;"><spanclass="math inline">\(p\)</span></td></tr><tr class="odd"><td style="text-align: center;"></td><td style="text-align: center;">R</td><td style="text-align: center;"><spanclass="math inline">\(90,10\)</span></td><td style="text-align: center;"><spanclass="math inline">\(20,80\)</span></td><td style="text-align: center;"><spanclass="math inline">\(1-p\)</span></td></tr><tr class="even"><td style="text-align: center;"></td><td style="text-align: center;"></td><td style="text-align: center;"><spanclass="math inline">\(q\)</span></td><td style="text-align: center;"><spanclass="math inline">\(1-q\)</span></td><td style="text-align: center;"></td></tr></tbody></table><p>改变的是：当V朝S的左边打，而S左倾时，双方的收益。此时，S的收益增大了，就是说S打反手球的能力增强了。</p><p>这里仍没有纯策略纳什均衡。</p><p>两个可能的影响：</p><p>（1）直接影响：S应该多左倾，即 <span class="math inline">\(q\)</span>变大（70>50）</p><p>（2）战略影响：V知道S打反手球的能力增强了，V选L的概率降低，于是S左倾的次数减少，即<span class="math inline">\(q\)</span> 变小</p><p>那么，<span class="math inline">\(q\)</span>到底是变大还是变小呢？下面重新求解NE：</p><p>为了找到S的新的 <span class="math inline">\(q\)</span>，利用V的收益</p><p><span class="math inline">\(L\to30q+80(1-q)\)</span></p><p><span class="math inline">\(R\to90q+20(1-q)\)</span></p><p>令 <span class="math inline">\(30q+80(1-q)=90q+20(1-q)\)</span></p><p>解得 <span class="math inline">\(q=0.5 < 0.6\)</span></p><p>可知，<span class="math inline">\(q\)</span>变小了，战略影响更大。</p><p><br /></p><p>《相对静态 (comparative statics)》</p><p>《带双方回到NE (bing each other back into NE)》</p><hr /><p>复习这篇笔记的原因：混合策略会最终提供一个数字上的结论，给出了对于决策的指导意见。</p>]]></content>
<categories>
<category>知识与理解</category>
</categories>
<tags>
<tag>博弈论公开课</tag>
</tags>
</entry>
<entry>
<title>知识搜索加油站</title>
<link href="/2019/11/13/relatedknow/"/>
<url>/2019/11/13/relatedknow/</url>
<content type="html"><![CDATA[<p>持续更新补充中···</p><hr /><p>硬分叉：比特币软件在升级的时候，如果不能向上兼容（老版本不认识新版本数据），老版本和新版本可以同时挖矿，最后产生两条各自独立的链条，这就是硬分叉。</p><p>2018年4月20日，AntPool宣布将会销毁12%从挖掘BCH中获得的交易费用。</p><div class="note primary"><p>销毁是指发往黑洞地址。“黑洞地址是公开的，谁都能查询，如果以后谁发现这个地址有转出纪录，那么比特币大陆的信誉肯定破产。”https://www.chainnode.com/post/159605（20191113）</p></div><span id="more"></span><p>把BCH理解为BTC的一种山寨币。BCH的EDA机制被利用产生了“算力暴击”，于是在2017年11月，BCH进行了硬分叉，BCH原链更名为“BitcoinClashic（BCHC）”，而分叉出来的链继承了BCH的名字。</p><p>“矿工之间是相互竞争的，谁的算力大，谁挖到的比特币就多，因此类似各个国家的军事竞赛，矿工之间陷入了囚徒困境的博弈状态。”</p><p>https://www.zhihu.com/question/265361492, 2019. [Online; accessed13-Nov-2019]</p>]]></content>
<categories>
<category>知识与理解</category>
</categories>
</entry>
<entry>
<title>20战争的消耗</title>
<link href="/2019/11/13/warcost/"/>
<url>/2019/11/13/warcost/</url>
<content type="html"><![CDATA[<p>这篇blog主要复习并整理了耶鲁大学博弈论公开课第20课的笔记。</p><hr /><p><strong>模型</strong></p><p>2个参与者：每个阶段各自选择<spanclass="math inline">\(\mathrm{F}\)</span>（攻击）或<spanclass="math inline">\(\mathrm{Q}\)</span>（退出），一方退出则博弈结束。</p><p>好消息：如果对方先退出，你将获得奖励<spanclass="math inline">\(\mathrm{V}\)</span></p><p>坏消息：每个阶段双方都选择攻击，那么每个人都要付出代价<spanclass="math inline">\(\mathrm{-C}\)</span></p><p>如果同时退出<span class="math inline">\(\rightarrow\)</span> <spanclass="math inline">\(\mathrm{0}\)</span></p><span id="more"></span><p><imgsrc="https://tva1.sinaimg.cn/large/006y8mN6ly1g9bj11zqaxj30u0140hdz.jpg" /></p><p><imgsrc="https://tva1.sinaimg.cn/large/006y8mN6ly1g9bj1su5pbj30u0140hdz.jpg" /></p>]]></content>
<categories>
<category>知识与理解</category>
</categories>
<tags>
<tag>博弈论公开课</tag>
</tags>
</entry>
<entry>
<title>连接实验室共享打印机</title>
<link href="/2019/11/11/printer/"/>
<url>/2019/11/11/printer/</url>
<content type="html"><![CDATA[<p><strong>一、Windows电脑连接步骤</strong></p><p>1、安装和打印机对应的驱动（实验室打印机驱动：<ahref="https://pan.baidu.com/s/1tD9BWSYvBwxXvE8RtxFUdw">百度网盘链接</a>提取码：xu7b <span id="more"></span></p><p>2、win+R，输入“\\<em>连接打印机主机的IP</em>”，回车<img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g6wzbnhld0j30bt076glp.jpg" alt="alt" style="zoom:67%;" /></p><p>3、在打印机上右键->连接。（实验室的打印机是下图中第一个）<img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g6wzchxkjrj30ks0g6q42.jpg" alt="alt" style="zoom: 50%;" /></p><hr /><p><strong>二、Mac连接步骤</strong>1、系统偏好设置->打印机与扫描仪->"+"号<img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g6wzdj9t50j310w0nw79h.jpg" alt="alt" style="zoom: 25%;" /></p><p>2、空白处右键->自定义工具栏，将“高级”拖入工具栏<img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g6wzducukqj30se0re42w.jpg" alt="alt" style="zoom:33%;" /></p><p>3、点击“高级”，填写（smb://10.21.235.88/HP%20LaserJet%201020%20(%E5%89%AF%E6%9C%AC%202）<img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g6wze4epihj30sg0ps43y.jpg" alt="alt" style="zoom:33%;" /></p><p>4、第一次打印时输入直接连接打印机的电脑的账号(Print)和密码(macprint)，如下图<img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g6wzecjrnvj30no0cimyz.jpg" alt="alt" style="zoom: 33%;" /></p>]]></content>
<categories>
<category>功能与技巧</category>
</categories>
</entry>
<entry>
<title>Mac下latex+sublime text 3安装与配置</title>
<link href="/2019/11/11/maclatex/"/>
<url>/2019/11/11/maclatex/</url>
<content type="html"><![CDATA[<p><strong>一、MacTex</strong></p><p><a href="http://tug.org/mactex/">官方下载</a></p><p><ahref="https://pan.baidu.com/s/1zbKNP3UhV-ELgZGHR6hzpg">百度网盘</a>密码:aqhq</p><span id="more"></span><p><strong>二、Sublime Text 3</strong></p><p><a href="http://www.sublimetext.com/3">官方下载</a></p><p><ahref="https://pan.baidu.com/s/1318l7rtoI886Hiwk51FnDA">百度网盘</a>密码:qqtk</p><p><strong>安装package control</strong></p><ol type="1"><li><p>打开Sublime Text 3</p></li><li><p>ctrl+`，打开控制台</p></li><li><p>粘贴如下代码，回车（<ahref="https://packagecontrol.io/installation">代码来源</a>）</p></li></ol><figure class="highlight python"><table><tr><td class="gutter"><div class="code-wrapper"><pre><span class="line">1</span><br></pre></div></td><td class="code"><pre><code class="hljs python"><span class="hljs-keyword">import</span> urllib.request,os,hashlib; h = <span class="hljs-string">'6f4c264a24d933ce70df5dedcf1dcaee'</span> + <span class="hljs-string">'ebe013ee18cced0ef93d5f746d80ef60'</span>; pf = <span class="hljs-string">'Package Control.sublime-package'</span>; ipp = sublime.installed_packages_path(); urllib.request.install_opener( urllib.request.build_opener( urllib.request.ProxyHandler()) ); by = urllib.request.urlopen( <span class="hljs-string">'http://packagecontrol.io/'</span> + pf.replace(<span class="hljs-string">' '</span>, <span class="hljs-string">'%20'</span>)).read(); dh = hashlib.sha256(by).hexdigest(); <span class="hljs-built_in">print</span>(<span class="hljs-string">'Error validating download (got %s instead of %s), please try manual install'</span> % (dh, h)) <span class="hljs-keyword">if</span> dh != h <span class="hljs-keyword">else</span> <span class="hljs-built_in">open</span>(os.path.join( ipp, pf), <span class="hljs-string">'wb'</span> ).write(by)<br></code></pre></td></tr></table></figure><ol start="4" type="1"><li>重启Sublime Text 3</li></ol><p>（关于packagecontrol安装启发：安装失败的时候，去找官方手册，比网络教程好用）</p><p><strong>安装Latextools</strong></p><ol type="1"><li><p>ctrl+shift+p，打开管理器</p></li><li><p>输入install，回车</p></li><li><p>输入Latextools</p></li></ol><p><strong>三、编译</strong></p><ol type="1"><li><p>编译环境：tools > build system > new buildsystem，复制以下内容，保存。（<ahref="https://www.moehrenzahn.de/How-to-create-a-custom-LaTeX-build-system-for-Sublime-Text/">参考</a>）</p><figure class="highlight nsis"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><code class="hljs nsis">{<br><br><span class="hljs-string">"cmd"</span>: [<span class="hljs-string">"rm -rf \`biber --cache` && latexmk -pdf -xelatex -silent -output-directory=output -interaction=nonstopmode \<span class="hljs-variable">$file_name</span> | grep -i -E \"</span>warn|!\<span class="hljs-string">" && open output/<span class="hljs-variable">$file_base_name.pdf</span>"</span>], <br><br><span class="hljs-string">"shell"</span>: <span class="hljs-literal">true</span>, <br><br><span class="hljs-string">"path"</span>: <span class="hljs-string">"<span class="hljs-variable">$PATH</span>:/usr/texbin:/usr/local/bin:/opt/local/bin:/usr/local/:/usr/local/texlive/2014/bin/x86_64-darwin/"</span>, <br><br><span class="hljs-string">"file_regex"</span>: <span class="hljs-string">"^(…*?):([0-9]*):?([0-9]*)"</span>, <br><br><span class="hljs-string">"selector"</span>: <span class="hljs-string">"text.tex.latex"</span> <br><br>}<br></code></pre></td></tr></table></figure></li><li><p>command+b操作两次，进行编译</p></li></ol>]]></content>
<categories>
<category>功能与技巧</category>
</categories>
</entry>
<entry>
<title>Hello World</title>
<link href="/2019/11/11/hello-world/"/>
<url>/2019/11/11/hello-world/</url>
<content type="html"><![CDATA[<p>Welcome to <a href="https://hexo.io/">Hexo</a>! This is your veryfirst post. Check <a href="https://hexo.io/docs/">documentation</a> formore info. If you get any problems when using Hexo, you can find theanswer in <ahref="https://hexo.io/docs/troubleshooting.html">troubleshooting</a> oryou can ask me on <ahref="https://github.com/hexojs/hexo/issues">GitHub</a>.</p><h2 id="quick-start">Quick Start</h2><span id="more"></span><h3 id="create-a-new-post">Create a new post</h3><figure class="highlight bash"><table><tr><td class="gutter"><div class="code-wrapper"><pre><span class="line">1</span><br></pre></div></td><td class="code"><pre><code class="hljs bash">$ hexo new <span class="hljs-string">"My New Post"</span><br></code></pre></td></tr></table></figure><p>More info: <ahref="https://hexo.io/docs/writing.html">Writing</a></p><h3 id="run-server">Run server</h3><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs bash">$ hexo server<br></code></pre></td></tr></table></figure><p>More info: <a href="https://hexo.io/docs/server.html">Server</a></p><h3 id="generate-static-files">Generate static files</h3><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs bash">$ hexo generate<br></code></pre></td></tr></table></figure><p>More info: <ahref="https://hexo.io/docs/generating.html">Generating</a></p><h3 id="deploy-to-remote-sites">Deploy to remote sites</h3><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs bash">$ hexo deploy<br></code></pre></td></tr></table></figure><p>More info: <ahref="https://hexo.io/docs/deployment.html">Deployment</a></p>]]></content>
<categories>
<category>功能与技巧</category>
</categories>
</entry>
<entry>
<title>博弈论论文集List(含中文摘要)</title>
<link href="/2019/11/11/papersCollection/"/>
<url>/2019/11/11/papersCollection/</url>
<content type="html"><![CDATA[<p>看发表在哪里的论文：四大安全会议<strong>CCS</strong>、<strong>NDSS</strong>、<strong>S&P(Oakland)</strong>、<strong>USENIX</strong></p><p><strong><font size="5">目录</font></strong></p><p><a href="#gap">18CCS_The Gap Game</a></p><p><a href="#instability">16CCS_On the Instability of Bitcoin Withoutthe Block Reward</a></p><p><a href="#poker">15CCS_How to Use Bitcoin to Play DecentralizedPoker</a></p><span id="more"></span><p><a href="#fire">15CCS_Liar, Liar, Coins on Fire PenalizingEquivocation By Loss of Bitcoins</a></p><p><a href="#coalitions">15CCS_Nonoutsourceable Scratch-Off Puzzles toDiscourage Bitcoin Mining Coalitions</a></p><p><a href="#coexistence">18S&P_Bitcoin vs. Bitcoin Cash Coexistenceor Downfall of Bitcoin Cash</a></p><p><a href="#dilemma">15S&P_The Miner's Dilemma</a></p><p><a href="#tor">15S&P_Bitcoin over Tor isn't a good idea</a></p><p><a href="#smartpool">17USENIX_SmartPool Practical DecentralizedPooled Mining</a></p><p><br /></p><p><font size="5"><strong>18CCS_The Gap Game</strong></font><spanid="gap"></span></p><p>间隙博弈</p><p> Blockchain-based cryptocurrencies secure a decentralized consensusprotocol by incentives. The protocol participants, called miners,generate (mine) a series of blocks, each containing monetarytransactions created by system users. As incentive for participation,miners receive newly minted currency and transaction fees paid bytransaction creators. Blockchain bandwidth limits lead users to payincreasing fees in order to prioritize their transactions. However, mostprior work focused on models where fees are negligible. In a notableexception, Carlsten et al. [17] postulated in CCS’16 that if incentivescome only from fees then a mining gap would form — miners would avoidmining when the available fees are insufficient.</p><p> In this work, we analyze cryptocurrency security in realisticsettings, taking into account all elements of expenses and rewards. Tostudy when gaps form, we analyze the system as a game we call the gapgame. We analyze the game with a combination of symbolic and numericanalysis tools in a wide range of scenarios.</p><p> Our analysis confirms Carlsten et al.’s postulate; indeed, we showthat gaps form well before fees are the only incentive, and analyze theimplications on security. Perhaps surprisingly, we show that differentminers choose different gap sizes to optimize their utility, even whentheir operating costs are identical. Alarmingly, we see that the systemincentivizes large miner coalitions, reducing system decentralization.We describe the required conditions to avoid the incentive misalignment,providing guidelines for future cryptocurrency design.</p><p>基于区块链的密码货币通过激励机制确保分布式共识协议的安全。协议参与者称为矿工，生成（挖矿）一系列块，每个块都包含由系统用户创建的货币的交易。作为参与的激励，矿工获得新的比特币和交易创造者支付的交易费用。区块链带宽限制导致用户支付越来越多的费用，以使自己的交易能被优先处理。然而，大多数之前的研究工作都集中在交易费可以忽略不计的模型上。值得关注的例外是，Carlsten等人[17]在CCS'16中假设，如果激励仅来自交易费，那么将形成一个挖矿间隙——当可获得的交易费不足时，矿工将避免挖矿。</p><p>在这项工作中，我们分析密码货币在现实设置中的安全性，考虑到所有的费用和报酬因素。为了研究间隙何时形成，我们将系统作为一个博弈来分析，我们称之为间隙博弈。我们结合符号和数字分析工具，在各种场景中分析这个博弈。</p><p>我们的分析证实了Carlsten等人的假设；事实上，我们表明，在交易费成为唯一的激励因素之前，间隙就已经形成，并分析了其对安全性的影响。或许令人惊讶的是，我们发现不同的矿工选择不同的间隙大小来优化他们的收益，即使他们的运营成本是相同的。令人担忧的是，我们看到，这一制度激励了大型矿业联盟，减少了制度分散化。我们描述了避免激励偏差的必要条件，为未来的加密货币设计提供了指导。</p><p><strong>BibTex</strong></p><figure class="highlight awk"><table><tr><td class="gutter"><div class="code-wrapper"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></div></td><td class="code"><pre><code class="hljs awk">@inproceedings{TsabaryE18,<br> author = {Itay Tsabary and<br> Ittay Eyal},<br> title = {The Gap Game},<br> booktitle = {Proceedings of the <span class="hljs-number">2018</span> {ACM} {SIGSAC} Conference on Computer and<br> Communications Security, {CCS} <span class="hljs-number">2018</span>, Toronto, ON, Canada, October<br> <span class="hljs-number">15</span>-<span class="hljs-number">19</span>, <span class="hljs-number">2018</span>},<br> pages = {<span class="hljs-number">713</span>--<span class="hljs-number">728</span>},<br> year = {<span class="hljs-number">2018</span>},<br> crossref = {DBLP:conf<span class="hljs-regexp">/ccs/</span><span class="hljs-number">2018</span>},<br> url = {https:<span class="hljs-regexp">//</span>doi.org<span class="hljs-regexp">/10.1145/</span><span class="hljs-number">3243734.3243737</span>},<br> doi = {<span class="hljs-number">10.1145</span>/<span class="hljs-number">3243734.3243737</span>},<br> timestamp = {Wed, <span class="hljs-number">21</span> Nov <span class="hljs-number">2018</span> <span class="hljs-number">12</span>:<span class="hljs-number">44</span>:<span class="hljs-number">06</span> +<span class="hljs-number">0100</span>},<br> biburl = {https:<span class="hljs-regexp">//</span>dblp.org<span class="hljs-regexp">/rec/</span>bib<span class="hljs-regexp">/conf/</span>ccs/TsabaryE18},<br> bibsource = {dblp computer science bibliography, https:<span class="hljs-regexp">//</span>dblp.org}<br>}<br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>16CCS_On the Instability of Bitcoin Withoutthe Block Reward</strong></font><span id="instability"></span></p><p>关于无块奖励比特币的不稳定性</p><p> Bitcoin provides two incentives for miners: block rewards andtransaction fees. The former accounts for thevast majority of minerrevenues at the beginning of the system, but it isexpected to transitionto the latter as the block rewards dwindle. There hasbeen an implicitbelief that whether miners are paid by block rewards ortransaction feesdoes not affect the security of the block chain.</p><p> We show that this is not the case. Our key insight is that with onlytransaction fees, the variance of theblock reward is very high due tothe exponentially distributed block arrival time,and it becomesattractive to fork a “wealthy" block to “steal" the rewards therein. Weshow that this results in an equilibrium with undesirable properties forBitcoin's security and performance, and even non-equilibria insomecircumstances. We also revisit selfish mining and show that it can bemade profitable for a miner with an arbitrarily low hash power share,and who isarbitrarily poorly connected within the network. Our resultsare derived from theoretical analysis and confirmed by a new Bitcoinmining simulator that maybe of independent interest.</p><p> We discuss the troubling implications of our results for Bitcoin'sfuture security and draw lessons for the design of newcryptocurrencies.</p><p>比特币为矿工提供了两种激励：区块奖励和交易费。前者在系统开始时占据了挖矿收入的绝大部分，但随着区块奖励的减少，它有望过渡到后者。有一种隐含的信念认为，矿工收入来自区块奖励还是交易费用不会影响区块链的安全。我们证明这不是事实。我们的关键观点是，只有交易费用，由于块到达时间呈指数分布，块奖励的方差非常高，因此，在其中叉出一个“富有”的块来“窃取”变得很有吸引力。</p><p>我们表明这不是事实。我们的关键观点是，当只有交易费用，由于块到达时间呈指数分布，块奖励的方差非常高，因此，从中叉出一个“富有”的块来“窃取”变得很有吸引力。我们表明，这会导致比特币的安全性和性能与不受欢迎的属性相平衡，甚至在某些情况下也会导致不平衡。我们还重新审视了自私挖矿，并表明，对于一个散列功率占比任意低，且在网络中连接不良的矿工来说，这是可以盈利的。我们的研究结果来源于理论分析，并被一个新的比特币挖矿模拟器所证实，该模拟器可能具有独立的吸引力。</p><p>我们讨论了我们的结果对比特币未来安全的令人不安的影响，并为新密码货币的设计吸取了经验教训。</p><p><strong>BibTex</strong></p><figure class="highlight awk"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br></pre></td><td class="code"><pre><code class="hljs awk">@inproceedings{CarlstenKWN16,<br> author = {Miles Carlsten and<br> Harry A. Kalodner and<br> S. Matthew Weinberg and<br> Arvind Narayanan},<br> title = {On the Instability of Bitcoin Without the Block Reward},<br> booktitle = {Proceedings of the <span class="hljs-number">2016</span> {ACM} {SIGSAC} Conference on Computer and<br> Communications Security, Vienna, Austria, October <span class="hljs-number">24</span>-<span class="hljs-number">28</span>, <span class="hljs-number">2016</span>},<br> pages = {<span class="hljs-number">154</span>--<span class="hljs-number">167</span>},<br> year = {<span class="hljs-number">2016</span>},<br> crossref = {DBLP:conf<span class="hljs-regexp">/ccs/</span><span class="hljs-number">2016</span>},<br> url = {https:<span class="hljs-regexp">//</span>doi.org<span class="hljs-regexp">/10.1145/</span><span class="hljs-number">2976749.2978408</span>},<br> doi = {<span class="hljs-number">10.1145</span>/<span class="hljs-number">2976749.2978408</span>},<br> timestamp = {Tue, <span class="hljs-number">06</span> Nov <span class="hljs-number">2018</span> <span class="hljs-number">11</span>:<span class="hljs-number">07</span>:<span class="hljs-number">30</span> +<span class="hljs-number">0100</span>},<br> biburl = {https:<span class="hljs-regexp">//</span>dblp.org<span class="hljs-regexp">/rec/</span>bib<span class="hljs-regexp">/conf/</span>ccs/CarlstenKWN16},<br> bibsource = {dblp computer science bibliography, https:<span class="hljs-regexp">//</span>dblp.org}<br>}<br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>15CCS_How to Use Bitcoin to Play DecentralizedPoker</strong></font><span id="poker"></span></p><p>如何用比特币玩分布式扑克</p><p> We present practical protocols for playing poker over the internetwithout having to trust a third party. Our poker protocols aredropout-tolerant in the sense that any party that drops out during themiddle of the game is forced to pay a monetary penalty to all otherparties.</p><p> More generally, we introduce and design protocols for secure cashdistribution with penalties, a primitive that simultaneously generalizessecure computation with penalties of Bentov and Kumaresan (Crypto 2014),and secure lottery with penalties of Andrychowicz et al. (Security andPrivacy 2014). Since secure cash distribution with penalties is areactive functionality by design, it suffices to capture a wide varietyof card games (including poker), board games, and auctions. Our protocolrealizing secure cash distribution with penalties works in a hybridmodel where parties have access to a claim-or-refund transactionfunctionality FCR which can be efficiently realized in (a variant of)Bitcoin.</p><p>我们提供了在网上玩扑克而不必信任第三方的实用协议。我们的扑克协议是允许退出的，前提是任何一方在游戏中途退出，都必须向所有其他方支付罚款。</p><p>更广泛地说，我们引入并设计了带惩罚的安全现金分配协议。这是一个原始的协议，它同时概括了Bentov和Kumaresan（Crypto2014）的安全计算惩罚进行归纳的原语，以及Andrychowicz等人（Security andPrivacy2014）的惩罚进行安全彩票。由于安全现金分配和惩罚是一个设计的反应性功能，它足以捕获各种各样的纸牌游戏（包括扑克）、棋盘游戏和拍卖。我们的协议实现了安全的现金分配和罚款，在混合模型中，当事方可以使用索赔或退款交易功能fcr，该功能可以在比特币（的变体）中有效实现。</p><p><strong>BibTex</strong></p><figure class="highlight awk"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><code class="hljs awk">@inproceedings{DBLP:conf<span class="hljs-regexp">/ccs/</span>KumaresanMB15,<br> author = {Ranjit Kumaresan and<br> Tal Moran and<br> Iddo Bentov},<br> title = {How to Use Bitcoin to Play Decentralized Poker},<br> booktitle = {Proceedings of the <span class="hljs-number">22</span>nd {ACM} {SIGSAC} Conference on Computer and<br> Communications Security, Denver, CO, USA, October <span class="hljs-number">12</span>-<span class="hljs-number">16</span>, <span class="hljs-number">2015</span>},<br> pages = {<span class="hljs-number">195</span>--<span class="hljs-number">206</span>},<br> year = {<span class="hljs-number">2015</span>},<br> crossref = {DBLP:conf<span class="hljs-regexp">/ccs/</span><span class="hljs-number">2015</span>},<br> url = {https:<span class="hljs-regexp">//</span>doi.org<span class="hljs-regexp">/10.1145/</span><span class="hljs-number">2810103.2813712</span>},<br> doi = {<span class="hljs-number">10.1145</span>/<span class="hljs-number">2810103.2813712</span>},<br> timestamp = {Tue, <span class="hljs-number">06</span> Nov <span class="hljs-number">2018</span> <span class="hljs-number">11</span>:<span class="hljs-number">07</span>:<span class="hljs-number">29</span> +<span class="hljs-number">0100</span>},<br> biburl = {https:<span class="hljs-regexp">//</span>dblp.org<span class="hljs-regexp">/rec/</span>bib<span class="hljs-regexp">/conf/</span>ccs/KumaresanMB15},<br> bibsource = {dblp computer science bibliography, https:<span class="hljs-regexp">//</span>dblp.org}<br>}<br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>15CCS_Liar, Liar, Coins on Fire!: PenalizingEquivocation By Loss of Bitcoins</strong></font><spanid="fire"></span></p><p>骗子，骗子，硬币起火！：通过丢失比特币惩罚模棱两可的一方</p><p> We show that equivocation, i.e., making conflicting statements toothers in a distributed protocol, can be monetarily disincentivized bythe use of crypto-currencies such as Bitcoin. To this end, we designcompletely decentralized non-equivocation contracts, which make itpossible to penalize an equivocating party by the loss of its money. Atthe core of these contracts, there is a novel cryptographic primitivecalled accountable assertions, which reveals the party’s Bitcoincredentials if it equivocates.</p><p> Non-equivocation contracts are particularly useful for distributedsystems that employ public append-only logs to protect data integrity,e.g., in cloud storage and social networks. Moreover, as double-spendingin Bitcoin is a special case of equivocation, the contracts enable us todesign a payment protocol that allows a payee to receive funds atseveral unsynchronized points of sale, while being able to penalize adouble-spending payer after the fact.</p><p>我们表明，在分布式协议中，模棱两可，即与其他人作出相互冲突的声明，可以通过使用比特币等加密货币从金钱上抑制。为此，我们设计了完全分散的非模棱两可的合同，使模棱两可的一方可能因损失金钱而受到惩罚。在这些合同的核心，有一个新的密码原语称为责任断言，它揭示了该方的比特币凭证，如果它含糊其辞。</p><p>非含糊合同对于使用公共仅附加日志来保护数据完整性的分布式系统尤其有用，例如在云存储和社交网络中。此外，由于比特币的双重支出是一种模棱两可的特殊情况，合同使我们能够设计一种支付协议，允许收款人在几个不同步的销售点接收资金，同时能够在事后惩罚双重支出的支付人。</p><p><strong>BibTex</strong></p><figure class="highlight dust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><code class="hljs dust"><span class="language-xml">@inproceedings</span><span class="hljs-template-variable">{RuffingKS15,</span><br><span class="hljs-template-variable"> author = {Tim Ruffing and</span><br><span class="hljs-template-variable"> Aniket Kate and</span><br><span class="hljs-template-variable"> Dominique Schr{\"{o}</span><span class="language-xml">}der},</span><br><span class="language-xml"> title = </span><span class="hljs-template-variable">{Liar, Liar, Coins on Fire!: Penalizing Equivocation By Loss of Bitcoins}</span><span class="language-xml">,</span><br><span class="language-xml"> booktitle = </span><span class="hljs-template-variable">{Proceedings of the 22nd {ACM}</span><span class="language-xml"> </span><span class="hljs-template-variable">{SIGSAC}</span><span class="language-xml"> Conference on Computer and</span><br><span class="language-xml"> Communications Security, Denver, CO, USA, October 12-16, 2015},</span><br><span class="language-xml"> pages = </span><span class="hljs-template-variable">{219--230}</span><span class="language-xml">,</span><br><span class="language-xml"> year = </span><span class="hljs-template-variable">{2015}</span><span class="language-xml">,</span><br><span class="language-xml"> crossref = </span><span class="hljs-template-variable">{DBLP:conf/ccs/2015}</span><span class="language-xml">,</span><br><span class="language-xml"> url = </span><span class="hljs-template-variable">{https://doi.org/10.1145/2810103.2813686}</span><span class="language-xml">,</span><br><span class="language-xml"> doi = </span><span class="hljs-template-variable">{10.1145/2810103.2813686}</span><span class="language-xml">,</span><br><span class="language-xml"> timestamp = </span><span class="hljs-template-variable">{Tue, 06 Nov 2018 11:07:29 +0100}</span><span class="language-xml">,</span><br><span class="language-xml"> biburl = </span><span class="hljs-template-variable">{https://dblp.org/rec/bib/conf/ccs/RuffingKS15}</span><span class="language-xml">,</span><br><span class="language-xml"> bibsource = </span><span class="hljs-template-variable">{dblp computer science bibliography, https://dblp.org}</span><span class="language-xml"></span><br><span class="language-xml">}</span><br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>15CCS_Nonoutsourceable Scratch-Off Puzzles toDiscourage Bitcoin Mining Coalitions</strong></font><spanid="coalitions"></span></p><p>不可外包的刮刮谜题以阻止比特币矿业联盟</p><p> An implicit goal of Bitcoin’s reward structure is to diffuse networkinfluence over a diverse, decentralized population of individualparticipants. Indeed, Bitcoin’s security claims rely on no single entitywielding a sufficiently large portion of the network’s overallcomputational power. Unfortunately, rather than participatingindependently, most Bitcoin miners join coalitions called mining poolsin which a central pool administrator largely directs the pool’sactivity, leading to a consolidation of power. Recently, the largestmining pool has accounted for more than half of network’s total miningcapacity. Relatedly, “hosted mining” service providers offer theirclients the benefit of economiesof- scale, tempting them away fromindependent participation. We argue that the prevalence of miningcoalitions is due to a limitation of the Bitcoin proof-of-work puzzle –specifically, that it affords an effective mechanism for enforcingcooperation in a coalition. We present several definitions andconstructions for “nonoutsourceable” puzzles that thwart suchenforcement mechanisms, thereby deterring coalitions. We also provide animplementation and benchmark results for our schemes to show they arepractical.</p><p>比特币奖励结构的一个隐含目标是将网络影响分散到不同的、分散的个人参与者群体中。事实上，比特币的安全声明并不依赖于任何一个实体使用网络整体计算能力的足够大的一部分。不幸的是，大多数比特币矿商没有独立参与，而是加入了一个称为“采矿池”的联盟，在这个联盟中，中央池管理员主要指导池的活动，从而导致权力的巩固。最近，最大的采矿池已经占到网络总采矿能力的一半以上。与此相关的是，“托管采矿”服务提供商为客户提供规模经济效益，吸引他们远离独立参与。我们认为，采矿联盟的盛行是由于比特币工作证明难题的局限性——特别是，它提供了一个有效的机制来加强联盟中的合作。我们对“不可外包”难题提出了几个定义和解释，这些难题阻碍了此类执行机制，从而阻碍了联盟。我们还为我们的方案提供了一个实现和基准结果，以证明它们是可行的。</p><p><strong>BibTex</strong></p><figure class="highlight awk"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><code class="hljs awk">@inproceedings{MillerKKS15,<br> author = {Andrew Miller and<br> Ahmed E. Kosba and<br> Jonathan Katz and<br> Elaine Shi},<br> title = {Nonoutsourceable Scratch-Off Puzzles to Discourage Bitcoin Mining<br> Coalitions},<br> booktitle = {Proceedings of the <span class="hljs-number">22</span>nd {ACM} {SIGSAC} Conference on Computer and<br> Communications Security, Denver, CO, USA, October <span class="hljs-number">12</span>-<span class="hljs-number">16</span>, <span class="hljs-number">2015</span>},<br> pages = {<span class="hljs-number">680</span>--<span class="hljs-number">691</span>},<br> year = {<span class="hljs-number">2015</span>},<br> crossref = {DBLP:conf<span class="hljs-regexp">/ccs/</span><span class="hljs-number">2015</span>},<br> url = {https:<span class="hljs-regexp">//</span>doi.org<span class="hljs-regexp">/10.1145/</span><span class="hljs-number">2810103.2813621</span>},<br> doi = {<span class="hljs-number">10.1145</span>/<span class="hljs-number">2810103.2813621</span>},<br> timestamp = {Mon, <span class="hljs-number">08</span> Jul <span class="hljs-number">2019</span> <span class="hljs-number">08</span>:<span class="hljs-number">49</span>:<span class="hljs-number">32</span> +<span class="hljs-number">0200</span>},<br> biburl = {https:<span class="hljs-regexp">//</span>dblp.org<span class="hljs-regexp">/rec/</span>bib<span class="hljs-regexp">/conf/</span>ccs/MillerKKS15},<br> bibsource = {dblp computer science bibliography, https:<span class="hljs-regexp">//</span>dblp.org}<br>}<br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>19S&P_Bitcoin vs. Bitcoin Cash:Coexistence or Downfall of Bitcoin Cash</strong></font><spanid="coexistence"></span></p><p>BTC vs. BCH：BCH的共存还是衰落</p><p> Bitcoin has become the most popular cryptocur- rency based on apeer-to-peer network. In Aug. 2017, Bitcoin was split into the originalBitcoin (BTC) and Bitcoin Cash (BCH). Since then, miners have had achoice between BTC and BCH mining because they have compatibleproof-of-work algorithms. Therefore, they can freely choose which cointo mine for higher profit, where the profitability depends on both thecoin price and mining difficulty. Some miners can immediately switch thecoin to mine only when mining difficulty changes because the difficultychanges are more predictable than that for the coin price, and we callthis behavior fickle mining.</p><p> In this paper, we study the effects of fickle mining by modeling agame between two coins. To do this, we consider both fickle miners andsome factions (e.g., BITMAIN for BCH mining) that stick to mining onecoin to maintain that chain. In this model, we show that fickle miningleads to a Nash equilibrium in which only a faction sticking to its coinmining remains as a loyal miner to the less valued coin (e.g., BCH),where loyal miners refer to those who conduct mining even after coinmining difficulty increases. This situation would cause severecentralization, weakening the security of the coin system.</p><p> To determine which equilibrium the competing coin systems (e.g., BTCvs. BCH) are moving toward, we traced the historical changes of miningpower for BTC and BCH and found that BCH often lacked loyal miners untilNov. 13, 2017, when the difficulty adjustment algorithm of BCH miningwas changed. However, the change in difficulty adjustment algorithm ofBCH mining led to a state close to the stable coexistence of BTC andBCH. We also demonstrate that the lack of BCH loyal miners may still bereached when a fraction of miners automatically and repeatedly switchesto the most profitable coin to mine (i.e., automatic mining). Accordingto our analysis, as of Dec. 2018, loyal miners to BCH would leave ifmore than about 5% of the total mining capacity for BTC and BCH hasengaged in the automatic mining. In addition, we analyze the recent“hash war” between Bitcoin ABC and SV, which confirms our theoreticalanalysis. Finally, we note that our results can be applied to anycompeting cryptocurrency systems in which the same hardware (e.g., ASICsor GPUs) can be used for mining. Therefore, our study brings new andimportant angles in competitive coin markets: a coin can intentionallyweaken the security and decentralization level of the other rival coinwhen mining hardware is shared between them, allowing for automaticmining.</p><p>比特币已经成为最流行的基于对等网络的加密技术。2017年8月，比特币分为原始比特币（BTC）和比特币现金（BCH）。从那以后，矿工们在btc和bch采矿之间有了选择，因为他们有兼容的工作证明算法。因此，他们可以自由选择开采哪种硬币以获得更高的利润，而利润率取决于硬币价格和开采难度。有些矿工只有在开采难度发生变化时才能立即将硬币换成矿币，因为难度的变化比硬币价格的变化更容易预测，我们称这种行为为变化无常的开采。</p><p>本文通过建立两个硬币之间的博弈模型，研究了易变开采的效果。为了做到这一点，我们考虑了易变的矿工和一些派别（例如，BCH矿业的Bitmain）坚持开采一枚硬币来维持这条链。在这个模型中，我们发现变化无常的开采导致了纳什均衡，在纳什均衡中，只有一个坚持其硬币开采的派别仍然是价值较低的硬币（如bch）的忠实矿工，忠诚矿工指的是那些即使在硬币开采难度增加后仍进行开采的人。这种情况将导致严重的集权，削弱硬币系统的安全性</p><p>为了确定竞争硬币系统（如BTC与BCH）走向哪种均衡，我们追踪了BTC与BCH采矿能力的历史变化，发现BCH在2017年11月13日BCH采矿难度调整算法改变之前，往往缺乏忠诚的矿工。然而，BCH挖掘中难度调整算法的改变导致了状态接近BTC和BCH的稳定共存。我们还证明，当一小部分矿工自动、反复地转换到利润最高的硬币进行开采（即自动开采）时，仍然可能会出现BCH忠诚矿工的短缺。根据我们的分析，截至2018年12月，如果BTC和BCH的总开采能力的5%以上从事自动开采，那么BCH的忠实矿工将离开。此外，我们分析了比特币ABC和SV之间最近的“散列战争”，这证实了我们的理论分析。最后，我们注意到，我们的结果可应用于任何竞争的加密货币系统，其中相同的硬件（如asic或gpu）可用于挖掘。因此，我们的研究为竞争性硬币市场带来了新的重要视角：当一枚硬币与另一枚硬币共享开采硬件时，它会有意削弱另一枚硬币的安全性和分散性水平，从而允许自动开采。</p><p><strong>BibTex</strong></p><figure class="highlight awk"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br></pre></td><td class="code"><pre><code class="hljs awk">@inproceedings{KwonKSK19,<br> author = {Yujin Kwon and<br> Hyoungshick Kim and<br> Jinwoo Shin and<br> Yongdae Kim},<br> title = {Bitcoin vs. Bitcoin Cash: Coexistence or Downfall of Bitcoin Cash?},<br> booktitle = {<span class="hljs-number">2019</span> {IEEE} Symposium on Security and Privacy, {SP} <span class="hljs-number">2019</span>, San Francisco,<br> CA, USA, May <span class="hljs-number">19</span>-<span class="hljs-number">23</span>, <span class="hljs-number">2019</span>},<br> pages = {<span class="hljs-number">935</span>--<span class="hljs-number">951</span>},<br> year = {<span class="hljs-number">2019</span>},<br> crossref = {DBLP:conf<span class="hljs-regexp">/sp/</span><span class="hljs-number">2019</span>},<br> url = {https:<span class="hljs-regexp">//</span>doi.org<span class="hljs-regexp">/10.1109/</span>SP.<span class="hljs-number">2019.00075</span>},<br> doi = {<span class="hljs-number">10.1109</span>/SP.<span class="hljs-number">2019.00075</span>},<br> timestamp = {Wed, <span class="hljs-number">16</span> Oct <span class="hljs-number">2019</span> <span class="hljs-number">14</span>:<span class="hljs-number">14</span>:<span class="hljs-number">51</span> +<span class="hljs-number">0200</span>},<br> biburl = {https:<span class="hljs-regexp">//</span>dblp.org<span class="hljs-regexp">/rec/</span>bib<span class="hljs-regexp">/conf/</span>sp/KwonKSK19},<br> bibsource = {dblp computer science bibliography, https:<span class="hljs-regexp">//</span>dblp.org}<br>}<br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>15S&P_The Miner'sDilemma</strong></font><span id="dilemma"></span></p><p>矿工困境</p><p> An open distributed system can be secured by requiring participantsto present proof of work and rewarding them for participation. TheBitcoin digital currency introduced this mechanism, which is adopted byalmost all contemporary digital currencies and related services. Anatural process leads participants of such systems to form pools, wheremembers aggregate their power and share the rewards. Experience withBitcoin shows that the largest pools are often open, allowing anyone tojoin. It has long been known that a member can sabotage an open pool byseemingly joining it but never sharing its proofs of work. The poolshares its revenue with the attacker, and so each of its participantsearns less. We define and analyze a game where pools use some of theirparticipants to infiltrate other pools and perform such an attack. Withany number of pools, no-pool-attacks is not a Nash equilibrium. We studythe special cases where either two pools or any number of identicalpools play the game and the rest of the participants are uninvolved. Inboth of these cases there exists an equilibrium that constitutes atragedy of the commons where the participating pools attack one anotherand earn less than they would have if none had attacked. For two pools,the decision whether or not to attack is the miner’s dilemma, aninstance of the iterative prisoner’s dilemma. The game is played dailyby the active Bitcoin pools, which apparently choose not to attack. Ifthis balance breaks, the revenue of open pools might diminish, makingthem unattractive to participants.</p><p> An opendistributed system can be secured by requiring participantsto present proof ofwork and rewarding them for participation. TheBitcoin digital currencyintroduced this mechanism, which is adopted byalmost all contemporary digitalcurrencies and related services.</p><p> A naturalprocess leads participants of such systems to form pools,where membersaggregate their power and share the rewards. Experiencewith Bitcoin shows thatthe largest pools are often open, allowing anyoneto join. It has long beenknown that a member can sabotage an open poolby seemingly joining it but neversharing its proofs of work. The poolshares its revenue with the attacker, andso each of its participantsearns less.</p><p> We define andanalyze a game where pools use some of theirparticipants to infiltrate otherpools and perform such an attack. Withany number of pools, no-pool-attacks isnot a Nash equilibrium. We studythe special cases where either two pools orany number of identical poolsplay the game and the rest of the participantsare uninvolved. In both ofthese cases there exists an equilibrium thatconstitutes a tragedy of thecommons where the participating pools attack oneanother and earn lessthan they would have if none had attacked.</p><p> For two pools,the decision whether or not to attack is the miner’sdilemma, an instanceof the iterative prisoner’s dilemma. The game isplayed daily by the activeBitcoin pools, which apparently choose not toattack. If this balance breaks,the revenue of open pools might diminish,making them unattractive toparticipants.</p><p>一个开放的分布式系统可以通过要求参与者出示工作证明并奖励他们的参与来得到保障。比特币数字货币引入了这种机制，几乎所有当代数字货币和相关服务都采用这种机制。一个自然的过程引导这些系统的参与者形成一个池，在那里成员聚集他们的力量并分享奖励。比特币的经验表明，最大的矿池往往是开放的，允许任何人加入。长期以来，人们都知道，一个成员可以通过加入一个开放池来破坏它，但从不分享它的工作证明。该池与攻击者共享其收入，因此每个参与者的收入都较低。我们定义并分析一个游戏，在这个博弈中，池使用一些参与者渗透到其他池中并执行这样的攻击。对于任意数量的池，没有池攻击不是纳什均衡。我们研究两个矿池或任何数量相同的矿池池玩游戏的特殊情况，其余的参与者不受干扰。在这两种情况下，都存在着一种平衡，这构成了一场公地悲剧，即参与池之间相互攻击，收入低于如果没有人攻击的话所能获得的收入。对于两个矿池，决定是否攻击是矿工困境，一个反复囚徒困境的例子。该游戏每天由活跃的比特币池进行，显然这些池选择了不攻击。如果这种平衡打破，开放池的收入可能会减少，使其对参与者没有吸引力。</p><p>开放式分布式系统可以通过要求参与者出示工作证明并奖励他们的参与来获得安全保障。比特币数字货币引入了这种机制，几乎所有现代数字货币和相关服务都采用这种机制。</p><p>一个自然的过程会引导这些系统的参与者形成一个池，在那里，成员们可以分享他们的权力和奖励。比特币的经验表明，最大的矿池往往是开放的，允许任何人加入。长期以来人们都知道，一个成员可以通过加入一个开放的矿池来破坏它，但却从不分享它的工作证明。该池与攻击者共享其收入，因此每个参与者的收入都较低。</p><p>我们定义并分析一个博弈，在这个博弈中，矿池使用他们的一些参与者渗透到其他游泳池并执行这样的攻击。对于任意数量的池，没有池攻击不是纳什均衡。我们研究两个游泳池或任意多个相同的游泳池玩游戏的特殊情况，其余的参与者则不参与其中。在这两种情况下，都存在着一种平衡，即公共场所的悲剧，参与的泳池互相攻击，赚的比没有人攻击的时候少。对于两个池，决定是否攻击是矿工困境，一个反复囚徒困境的例子。这个游戏每天都由activebitcoin池进行，显然他们选择不攻击。如果这种平衡打破，开放式游泳池的收入可能会减少，使其对参与者没有吸引力。</p><p><strong>BibTex</strong></p><figure class="highlight dust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><code class="hljs dust"><span class="language-xml">@inproceedings</span><span class="hljs-template-variable">{Eyal15,</span><br><span class="hljs-template-variable"> author = {Ittay Eyal}</span><span class="language-xml">,</span><br><span class="language-xml"> title = </span><span class="hljs-template-variable">{The Miner's Dilemma}</span><span class="language-xml">,</span><br><span class="language-xml"> booktitle = </span><span class="hljs-template-variable">{2015 {IEEE}</span><span class="language-xml"> Symposium on Security and Privacy, </span><span class="hljs-template-variable">{SP}</span><span class="language-xml"> 2015, San Jose,</span><br><span class="language-xml"> CA, USA, May 17-21, 2015},</span><br><span class="language-xml"> pages = </span><span class="hljs-template-variable">{89--103}</span><span class="language-xml">,</span><br><span class="language-xml"> year = </span><span class="hljs-template-variable">{2015}</span><span class="language-xml">,</span><br><span class="language-xml"> crossref = </span><span class="hljs-template-variable">{DBLP:conf/sp/2015}</span><span class="language-xml">,</span><br><span class="language-xml"> url = </span><span class="hljs-template-variable">{https://doi.org/10.1109/SP.2015.13}</span><span class="language-xml">,</span><br><span class="language-xml"> doi = </span><span class="hljs-template-variable">{10.1109/SP.2015.13}</span><span class="language-xml">,</span><br><span class="language-xml"> timestamp = </span><span class="hljs-template-variable">{Wed, 16 Oct 2019 14:14:51 +0200}</span><span class="language-xml">,</span><br><span class="language-xml"> biburl = </span><span class="hljs-template-variable">{https://dblp.org/rec/bib/conf/sp/Eyal15}</span><span class="language-xml">,</span><br><span class="language-xml"> bibsource = </span><span class="hljs-template-variable">{dblp computer science bibliography, https://dblp.org}</span><span class="language-xml"></span><br><span class="language-xml">}</span><br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>15S&P_Bitcoin over Tor isn't a goodidea</strong></font><span id="tor"></span></p><p>比特币对Tor来说不是个好主意</p><p> Bitcoin is a decentralized P2P digital currency in which coins aregenerated by a distributed set of miners and transactions arebroadcasted via a peer-to-peer network. While Bitcoin provides somelevel of anonymity (or rather pseudonymity) by encouraging the users tohave any number of random-looking Bitcoin addresses, recent researchshows that this level of anonymity is rather low. This encourages usersto connect to the Bitcoin network through anonymizers like Tor andmotivates development of default Tor functionality for popular mobileSPV clients. In this paper we show that combining Tor and Bitcoincreates a new attack vector. A low-resource attacker can gain fullcontrol of information flows between all users who chose to use Bitcoinover Tor. In particular the attacker can link together user’stransactions regardless of pseudonyms used, control which Bitcoin blocksand transactions are relayed to user and can delay or discard user’stransactions and blocks. Moreover, we show how an attacker canfingerprint users and then recognize them and learn their IP addresseswhen they decide to connect to the Bitcoin network directly.</p><p>比特币是一种分布式的P2P数字货币，其中硬币由一组分散的矿工产生，交易通过对等网络广播。虽然比特币通过鼓励用户拥有任意数量的随机看起来的比特币地址来提供某种程度的匿名性（或更确切地说是假名），但最近的研究表明，这种匿名性水平相当低。这鼓励用户通过匿名者（如Tor）连接比特币网络，并推动流行移动SPV客户机的默认Tor功能的开发。本文证明了Tor和比特币的结合产生了一种新的攻击向量。低资源攻击者可以完全控制所有选择使用比特币而非Tor的用户之间的信息流。特别是，攻击者可以将用户的交易链接在一起，而不考虑使用的假名，控制将哪些比特币区块和交易中继给用户，并可以延迟或丢弃用户的交易和区块。此外，我们还演示了攻击者如何在决定直接连接比特币网络时，对用户进行指纹识别，然后识别他们并学习他们的IP地址。</p><p><strong>BibTex</strong></p><figure class="highlight dust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><code class="hljs dust"><span class="language-xml">@inproceedings</span><span class="hljs-template-variable">{BiryukovP15,</span><br><span class="hljs-template-variable"> author = {Alex Biryukov and</span><br><span class="hljs-template-variable"> Ivan Pustogarov}</span><span class="language-xml">,</span><br><span class="language-xml"> title = </span><span class="hljs-template-variable">{Bitcoin over Tor isn't a Good Idea}</span><span class="language-xml">,</span><br><span class="language-xml"> booktitle = </span><span class="hljs-template-variable">{2015 {IEEE}</span><span class="language-xml"> Symposium on Security and Privacy, </span><span class="hljs-template-variable">{SP}</span><span class="language-xml"> 2015, San Jose,</span><br><span class="language-xml"> CA, USA, May 17-21, 2015},</span><br><span class="language-xml"> pages = </span><span class="hljs-template-variable">{122--134}</span><span class="language-xml">,</span><br><span class="language-xml"> year = </span><span class="hljs-template-variable">{2015}</span><span class="language-xml">,</span><br><span class="language-xml"> crossref = </span><span class="hljs-template-variable">{DBLP:conf/sp/2015}</span><span class="language-xml">,</span><br><span class="language-xml"> url = </span><span class="hljs-template-variable">{https://doi.org/10.1109/SP.2015.15}</span><span class="language-xml">,</span><br><span class="language-xml"> doi = </span><span class="hljs-template-variable">{10.1109/SP.2015.15}</span><span class="language-xml">,</span><br><span class="language-xml"> timestamp = </span><span class="hljs-template-variable">{Wed, 16 Oct 2019 14:14:51 +0200}</span><span class="language-xml">,</span><br><span class="language-xml"> biburl = </span><span class="hljs-template-variable">{https://dblp.org/rec/bib/conf/sp/BiryukovP15}</span><span class="language-xml">,</span><br><span class="language-xml"> bibsource = </span><span class="hljs-template-variable">{dblp computer science bibliography, https://dblp.org}</span><span class="language-xml"></span><br><span class="language-xml">}</span><br></code></pre></td></tr></table></figure><p><br /></p><p><font size="5"><strong>17USENIX_SmartPool: Practical DecentralizedPooled Mining</strong></font><span id="smartpool"></span></p><p>智能池：实用分散式池挖矿</p><p> Cryptocurrenciessuch as Bitcoin and Ethereum are operated by ahandful of mining pools. Nearly95% of Bitcoin’s and 80% of Ethereum’smining power resides with less than tenand six mining poolsrespectively. Although miners benefit from low payoutvariance in pooledmining, centralized mining pools require members to trust thatpooloperators will remunerate them fairly. Furthermore, centralized poolsposethe risk of transaction censorship from pool operators, and openuppossibilities for collusion between pools for perpetrating severeattacks.</p><p> In this work, wepropose SMARTPOOL, a novel protocol design foradecentralized mining pool. Our protocol shows how one can leveragesmartcontracts, autonomous blockchainprograms, to decentralizecryptocurrency mining. SMARTPOOL gives transaction selection controlbackto miners while yielding lowvariance payouts. SMARTPOOL incurs miningfees lower thancentralized mining pools and is designed to scale to alarge number of miners.We implemented and deployed a robust SMARTPOOLimplementation on the Ethereum and Ethereum Classicnetworks. To date,our deployed pools have handled a peak hashrate of 30 GHsfrom Ethereumminers, resulting in 105 blocks, costing miners a mere 0:6% of blockrewards in transaction fees.</p><p>比特币和以太坊等加密货币由少数采矿池操作。比特币近95%和以太坊80%的采矿权分别位于少于Tenand和6个采矿池。尽管矿商从集中开采的低回报差异中获益，但集中开采池要求成员相信集中开采池运营商会公平地给予他们报酬。此外，集中池还存在来自池运营商的交易审查风险，并公开支持池之间串通实施严重攻击。</p><p> 在这项工作中，weproposesmartpool是一种新的集中式挖掘池协议设计。我们的协议展示了如何利用智能合约、自主区块链程序分散加密货币挖掘。SmartPool为矿工提供事务选择控制，同时产生低方差支出。智能池产生的采矿费用低于集中采矿池，旨在扩大到大量矿工。我们在以太坊和以太坊ClassicNetworks上实施并部署了强大的智能池实施。到目前为止，我们部署的池已经处理了以太坊矿工30GHS的峰值哈希率，导致105个区块，仅为交易费用中区块奖励的0:6%。</p><p><strong>BibTex</strong></p><figure class="highlight awk"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><code class="hljs awk">@inproceedings{LuuVTS17,<br> author = {Loi Luu and<br> Yaron Velner and<br> Jason Teutsch and<br> Prateek Saxena},<br> title = {SmartPool: Practical Decentralized Pooled Mining},<br> booktitle = {<span class="hljs-number">26</span>th {USENIX} Security Symposium, {USENIX} Security <span class="hljs-number">2017</span>, Vancouver,<br> BC, Canada, August <span class="hljs-number">16</span>-<span class="hljs-number">18</span>, <span class="hljs-number">2017</span>.},<br> pages = {<span class="hljs-number">1409</span>--<span class="hljs-number">1426</span>},<br> year = {<span class="hljs-number">2017</span>},<br> crossref = {DBLP:conf<span class="hljs-regexp">/uss/</span><span class="hljs-number">2017</span>},<br> url = {https:<span class="hljs-regexp">//</span>www.usenix.org<span class="hljs-regexp">/conference/u</span>senixsecurity17<span class="hljs-regexp">/technical-sessions/</span>presentation/luu},<br> timestamp = {Fri, <span class="hljs-number">01</span> Sep <span class="hljs-number">2017</span> <span class="hljs-number">12</span>:<span class="hljs-number">29</span>:<span class="hljs-number">11</span> +<span class="hljs-number">0200</span>},<br> biburl = {https:<span class="hljs-regexp">//</span>dblp.org<span class="hljs-regexp">/rec/</span>bib<span class="hljs-regexp">/conf/u</span>ss/LuuVTS17},<br> bibsource = {dblp computer science bibliography, https:<span class="hljs-regexp">//</span>dblp.org}<br>}<br></code></pre></td></tr></table></figure>]]></content>
<categories>
<category>论文与线索</category>
</categories>
</entry>
<entry>
<title>Hexo支持LaTex公式</title>
<link href="/2019/11/07/hexolatex/"/>
<url>/2019/11/07/hexolatex/</url>
<content type="html"><![CDATA[<p>问题：<strong>如何让Hexo的blog页面正常显示LaTex公式</strong></p><p>解决方法：</p><p>1、<code>npm uninstall hexo-math --save</code></p><p>2、<code>npm install hexo-renderer-mathjax --save</code></p><p>3、<code>npm uninstall hexo-renderer-marked --save</code></p><span id="more"></span><p>4、<code>npm install hexo-renderer-kramed --save</code></p><p>5、修改/<em>yourBlogFolder</em>/node_moudles/hexo-renderer-mathjax/mathjax.html</p><p>修改的是src中http......latest.js这一部分的内容，具体改成什么地址参见<ahref="%5Bhttps://www.mathjax.org/#gettingstarted%EF%BC%8C%E8%BF%99%E6%98%AF%E6%9C%80%E6%96%B0%E7%9A%84Mathjax%5D(https://www.mathjax.org/#gettingstarted，这是最新的Mathjax)">这里</a>的NEWS页面</p><p><imgsrc="https://tva1.sinaimg.cn/large/006y8mN6ly1g8pig7meshj319c0d2ju6.jpg" /></p><p>6、修改主题配置文件（themes>nest>_config.yml）<imgsrc="https://tva1.sinaimg.cn/large/006y8mN6ly1g8pi63fa83j314k0do0vl.jpg" /></p><p>7、在需要LaTex渲染的post的Front-matter里写上mathjax: true<img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g8piy0ceb1j31a20hy40k.jpg" style="zoom: 48%;" /></p>]]></content>
<categories>
<category>功能与技巧</category>
</categories>
<tags>
<tag>solution</tag>
<tag>latex</tag>
</tags>
</entry>
<entry>
<title>Hexo页面不更新</title>
<link href="/2019/11/06/nohexo/"/>
<url>/2019/11/06/nohexo/</url>
<content type="html"><![CDATA[<p>问题：<strong>执行hexo g -d后，github仓库更新了，但是blog页面没有更新</strong></p><p>解决方法：</p><span id="more"></span><ol type="1"><li><code>git remote add origin https://github.com/Kacikaci/Kacikaci.github.io.git</code></li><li><code>git remote -v</code></li><li><code>git remote rm Cuiwen</code></li></ol><p>总的来说就是，只留下origin</p><p><img src="https://tva1.sinaimg.cn/large/006y8mN6ly1g8o4xeoq5aj30qa08o77f.jpg" style="zoom: 50%;" /></p><p>或者-</p><p>也有可能是因为一篇post的标题太长或者标题中出现了“|”等符号，导致没有办法更新页面。这种时候，标题取简单一点，并且不要出现特别的符号就可以了。</p>]]></content>
<categories>
<category>功能与技巧</category>
</categories>
</entry>
</search>