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11 \usepackage{tikz} |
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30 |
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45 \definecolor{javared}{rgb}{0.6,0,0} % for strings |
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48 \definecolor{javadocblue}{rgb}{0.25,0.35,0.75} % javadoc |
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49 |
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50 \lstset{language=Java, |
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51 basicstyle=\ttfamily, |
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52 keywordstyle=\color{javapurple}\bfseries, |
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55 morecomment=[s][\color{javadocblue}]{/**}{*/}, |
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60 tabsize=2, |
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61 showspaces=false, |
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62 showstringspaces=false} |
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63 |
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64 \lstdefinelanguage{scala}{ |
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65 morekeywords={abstract,case,catch,class,def,% |
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73 sensitive=true, |
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76 morestring=[b]", |
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78 morestring=[b]""" |
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79 } |
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80 |
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81 \lstset{language=Scala, |
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82 basicstyle=\ttfamily, |
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83 keywordstyle=\color{javapurple}\bfseries, |
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84 stringstyle=\color{javagreen}, |
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85 commentstyle=\color{javagreen}, |
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86 morecomment=[s][\color{javadocblue}]{/**}{*/}, |
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87 numbers=left, |
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89 stepnumber=1, |
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90 numbersep=10pt, |
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91 tabsize=2, |
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92 showspaces=false, |
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93 showstringspaces=false} |
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94 |
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95 % beamer stuff |
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96 \renewcommand{\slidecaption}{APP 09, King's College London, 27 November 2012} |
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97 \newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}% for definitions |
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98 \newcommand{\bl}[1]{\textcolor{blue}{#1}} |
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99 |
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100 \begin{document} |
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101 |
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102 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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103 \mode<presentation>{ |
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104 \begin{frame}<1>[t] |
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105 \frametitle{% |
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106 \begin{tabular}{@ {}c@ {}} |
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107 \\ |
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108 \LARGE Access Control and \\[-3mm] |
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109 \LARGE Privacy Policies (9)\\[-6mm] |
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110 \end{tabular}}\bigskip\bigskip\bigskip |
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111 |
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112 %\begin{center} |
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113 %\includegraphics[scale=1.3]{pics/barrier.jpg} |
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114 %\end{center} |
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115 |
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116 \normalsize |
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117 \begin{center} |
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118 \begin{tabular}{ll} |
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119 Email: & christian.urban at kcl.ac.uk\\ |
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120 Of$\!$fice: & S1.27 (1st floor Strand Building)\\ |
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121 Slides: & KEATS (also homework is there)\\ |
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122 \end{tabular} |
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123 \end{center} |
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124 |
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125 \end{frame}} |
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126 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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127 |
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128 |
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129 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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130 \mode<presentation>{ |
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131 \begin{frame}[c] |
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132 \frametitle{Last Week} |
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133 |
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134 Recall, the Schroeder-Needham (1978) protocol is vulnerable to replay attacks. |
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135 |
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136 \begin{center} |
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137 \begin{tabular}{@{}r@ {\hspace{1mm}}l@{}} |
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138 \bl{$A \rightarrow S :$} & \bl{$A, B, N_A$}\\ |
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139 \bl{$S \rightarrow A :$} & \bl{$\{N_A, B, K_{AB},\{K_{AB}, A\}_{K_{BS}} \}_{K_{AS}}$}\\ |
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140 \bl{$A \rightarrow B :$} & \bl{$\{K_{AB}, A\}_{K_{BS}} $}\\ |
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141 \bl{$B \rightarrow A :$} & \bl{$\{N_B\}_{K_{AB}}$}\\ |
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142 \bl{$A \rightarrow B :$} & \bl{$\{N_B-1\}_{K_{AB}}$}\\ |
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143 \end{tabular} |
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144 \end{center}\pause |
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145 |
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146 Fix: Replace messages 2 and 3 to include a timestamp:\bigskip |
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147 |
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148 \begin{minipage}{1.1\textwidth} |
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149 \begin{center} |
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150 \begin{tabular}{@{\hspace{-2mm}}r@ {\hspace{1mm}}l@{}} |
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151 \bl{$S \rightarrow A :$} & \bl{$\{N_A, B, K_{\!AB}, T_S, \!\{K_{\!AB}, A, T_S\}_{K_{BS}} \}_{K_{AS}}$}\\ |
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152 \bl{$A \rightarrow B :$} & \bl{$\{K_{AB}, A, T_S\}_{K_{BS}} $}\\ |
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153 \end{tabular} |
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154 \end{center} |
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155 \end{minipage} |
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156 |
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157 \end{frame}} |
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158 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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159 |
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160 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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161 \mode<presentation>{ |
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162 \begin{frame}[t] |
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163 \frametitle{Denning-Sacco Protocol} |
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164 |
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165 Denning-Sacco (1981) suggested to add the timestamp, but omit the handshake:\bigskip |
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166 |
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167 \begin{minipage}{1.1\textwidth} |
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168 \begin{center} |
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169 \begin{tabular}{@{\hspace{-2mm}}r@ {\hspace{1mm}}l@{}} |
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170 \bl{$A \rightarrow S :$} & \bl{$A, B, N_A$}\\ |
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171 \bl{$S \rightarrow A :$} & \bl{$\{N_A, B, K_{\!AB}, T_S, \!\{K_{\!AB}, A, T_S\}_{K_{BS}} \}_{K_{AS}}$}\\ |
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172 \bl{$A \rightarrow B :$} & \bl{$\{K_{AB}, A, T_S\}_{K_{BS}} $}\\ |
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173 \textcolor{lightgray}{$B \rightarrow A :$} & \textcolor{lightgray}{$\{N_B\}_{K_{AB}}$}\\ |
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174 \textcolor{lightgray}{$A \rightarrow B :$} & \textcolor{lightgray}{$\{N_B-1\}_{K_{AB}}$}\\ |
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175 \end{tabular} |
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176 \end{center} |
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177 \end{minipage}\bigskip |
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178 |
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179 they argue \bl{$A$} and \bl{$B$} can check that the messages are not replays of earlier |
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180 runs, by checking the time difference when the protocol is last used |
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181 \end{frame}} |
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182 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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183 |
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184 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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185 \mode<presentation>{ |
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186 \begin{frame}[t] |
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187 \frametitle{Denning-Sacco-Lowe Protocol} |
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188 |
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189 Lowe (1997) disagreed and said the handshake should be kept, |
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190 otherwise:\bigskip |
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191 |
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192 \begin{minipage}{1.1\textwidth} |
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193 \begin{center} |
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194 \begin{tabular}{@{\hspace{-7mm}}r@ {\hspace{1mm}}l@{}} |
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195 \bl{$A \rightarrow S :$} & \bl{$A, B, N_A$}\\ |
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196 \bl{$S \rightarrow A :$} & \bl{$\{N_A, B, K_{\!AB}, T_S, \!\{K_{\!AB}, A, T_S\}_{K_{BS}} \}_{K_{AS}}$}\\ |
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197 \bl{$A \rightarrow B :$} & \bl{$\{K_{AB}, A, T_S\}_{K_{BS}} $}\\ |
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198 \bl{$I(A) \rightarrow B :$} & \bl{$\{K_{AB}, A, T_S\}_{K_{BS}} $}\hspace{5mm}\textcolor{black}{replay}\\ |
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199 \end{tabular} |
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200 \end{center} |
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201 \end{minipage}\bigskip |
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202 |
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203 When is this a problem?\pause\medskip |
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204 |
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205 Assume \bl{$B$} is a bank and the message is ``Draw \pounds{1000} from \bl{$A$}'s |
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206 account and transfer it to \bl{$I$}.'' |
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207 \end{frame}} |
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208 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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209 |
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210 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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211 \mode<presentation>{ |
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212 \begin{frame}[t] |
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213 \frametitle{Privacy} |
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214 |
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215 \begin{minipage}{1.05\textwidth} |
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216 \begin{itemize} |
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217 \item we \alert{do} want that government data is made public (free maps for example) |
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218 \item we \alert{do not} want that medical data becomes public (similarly tax data, school |
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219 records, job offers)\bigskip |
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220 \item personal information can potentially lead to fraud |
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221 (identity theft) |
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222 \end{itemize}\pause |
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223 |
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224 {\bf ``The reality'':} |
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225 \only<2>{\begin{itemize} |
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226 \item London Health Programmes lost in June unencrypted details of more than 8 million people |
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227 (no names, but postcodes and details such as gender, age and ethnic origin) |
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228 \end{itemize}} |
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229 \only<3>{\begin{itemize} |
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230 \item also in June Sony got hacked: over 1M users' personal information, including passwords, email addresses, home addresses, dates of birth, and all Sony opt-in data associated with their accounts. |
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231 \end{itemize}} |
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232 \end{minipage} |
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233 |
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234 \end{frame}} |
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235 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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236 |
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237 |
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238 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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239 \mode<presentation>{ |
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240 \begin{frame}[c] |
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241 \frametitle{Privacy and Big Data} |
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242 |
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243 Selected sources of ``Big Data'': |
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244 |
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245 \begin{itemize} |
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246 \item Facebook |
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247 \begin{itemize} |
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248 \item 40+ Billion photos (100 PB) |
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249 \item 6 Billion messages daily (5 - 10 TB) |
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250 \item 900 Million users |
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251 \end{itemize} |
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252 \item Common Crawl |
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253 \begin{itemize} |
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254 \item covers 3.8 Billion webpages (2012 dataset) |
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255 \item 50 TB of data |
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256 \end{itemize} |
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257 \item Google |
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258 \begin{itemize} |
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259 \item 20 PB daily (2008) |
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260 \end{itemize} |
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261 \item Twitter |
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262 \begin{itemize} |
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263 \item 7 Million users in the UK |
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264 \item a company called Datasift is allowed to mine all tweets since 2010 |
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265 \item they charge 10k per month for other companies to target advertisement |
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266 \end{itemize} |
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267 \end{itemize}\pause |
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268 |
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269 |
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270 \end{frame}} |
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271 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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272 |
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273 |
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274 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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275 \mode<presentation>{ |
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276 \begin{frame}[c] |
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277 \frametitle{Cookies} |
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278 |
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279 ``We have published a new cookie policy. It explains what cookies are |
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280 and how we use them on our site. To learn more about cookies and |
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281 their benefits, please view our cookie policy.\medskip |
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282 |
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283 If you'd like to disable cookies on this device, please view our information |
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284 pages on 'How to manage cookies'. Please be aware that parts of the |
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285 site will not function correctly if you disable cookies. \medskip |
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286 |
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287 By closing this |
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288 message, you consent to our use of cookies on this device in accordance |
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289 with our cookie policy unless you have disabled them.'' |
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290 |
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291 |
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292 \end{frame}} |
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293 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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294 |
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295 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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296 \mode<presentation>{ |
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297 \begin{frame}[c] |
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298 \frametitle{Scare Tactics} |
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299 |
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300 ``As we explain in our Cookie Policy, cookies help you to get the most |
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301 out of our websites.\medskip |
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302 |
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303 If you do disable our cookies you may find that certain sections of our |
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304 website do not work. For example, you may have difficulties logging in |
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305 or viewing articles.'' |
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306 |
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307 |
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308 |
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309 |
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310 \end{frame}} |
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311 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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312 |
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313 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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314 \mode<presentation>{ |
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315 \begin{frame}[c] |
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316 \frametitle{Netflix Prize} |
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317 |
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318 Anonymity is \alert{necessary} for privacy, but \alert{not} enough!\bigskip |
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319 |
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320 \begin{itemize} |
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321 \item Netflix offered in 2006 (and every year until 2010) a 1 Mio \$ prize for improving their movie rating algorithm |
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322 \item dataset contained 10\% of all Netflix users (appr.~500K) |
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323 \item names were removed, but included numerical ratings as well as times of rating |
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324 \item average user rated 200 movies |
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325 \item some information was \alert{perturbed} (i.e., slightly modified) |
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326 \end{itemize} |
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327 |
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328 \hfill{\bf\alert{All OK?}} |
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329 |
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330 \end{frame}} |
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331 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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332 |
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333 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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334 \mode<presentation>{ |
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335 \begin{frame}[c] |
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336 \frametitle{Re-identification Attack} |
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337 |
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338 Two researchers analysed the data: |
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339 |
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340 \begin{itemize} |
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341 \item with 8 ratings (2 of them can be wrong) and dates that have a 14-day error, 98\% of the |
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342 records can be identified |
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343 \item for 68\% only two ratings and dates are sufficient (for movie ratings outside the top 500)\bigskip\pause |
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344 \item they took 50 samples from IMDb (where people can reveal their identity) |
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345 \item 2 of them uniquely identified entries in the Netflix database (either by movie rating or by dates) |
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346 \end{itemize} |
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347 |
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348 \end{frame}} |
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349 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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350 |
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351 |
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352 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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353 \mode<presentation>{ |
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354 \begin{frame}[c] |
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355 \frametitle{} |
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356 |
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357 \begin{itemize} |
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358 \item Birth data, postcode and gender (unique for\\ 87\% of the US population) |
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359 \item Preferences in movies (99\% of 500K for 8 ratings) |
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360 \end{itemize}\bigskip |
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361 |
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362 Therefore best practices / or even law: |
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363 |
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364 \begin{itemize} |
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365 \item only year dates (age: 90 years or over), |
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366 \item no postcodes (sector data is OK, similarly in the US)\\ |
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367 \textcolor{gray}{no names, addresses, account numbers, licence plates} |
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368 \item disclosure information needs to be retained for 5 years |
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369 \end{itemize} |
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370 |
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371 \end{frame}} |
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372 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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373 |
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374 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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375 \mode<presentation>{ |
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376 \begin{frame}[c] |
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377 \frametitle{How to Safely Disclose Information?} |
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378 |
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379 \only<1>{ |
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380 \begin{itemize} |
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381 \item Assume you make a survey of 100 randomly chosen people. |
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382 \item Say 99\% of the people in the 10 - 40 age group have seen the |
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383 Gangnam video on youtube.\bigskip |
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384 |
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385 \item What can you infer about the rest of the population? |
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386 \end{itemize}} |
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387 \only<2>{ |
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388 \begin{itemize} |
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389 \item Is it possible to re-identify data later, if more data is released. \bigskip\bigskip\pause |
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390 |
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391 \item Not even releasing only aggregate information prevents re-identification attacks. |
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392 (GWAS was a public database of gene-frequency studies linked to diseases; |
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393 you only needed enough data about phenotype (hair, eyes, skin colour...) in order |
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394 to identify whether an individual was part of the study --- DB closed in 2008) |
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395 \end{itemize}} |
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396 |
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397 \end{frame}} |
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398 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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399 |
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400 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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401 \mode<presentation>{ |
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402 \begin{frame}[c] |
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403 \frametitle{Differential Privacy} |
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404 |
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405 \begin{center} |
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406 User\;\;\;\; |
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407 \begin{tabular}{c} |
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408 tell me \bl{$f(x)$} $\Rightarrow$\\ |
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409 $\Leftarrow$ \bl{$f(x) + \text{noise}$} |
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410 \end{tabular} |
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411 \;\;\;\;\begin{tabular}{@{}c} |
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412 Database\\ |
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413 \bl{$x_1, \ldots, x_n$} |
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414 \end{tabular} |
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415 \end{center} |
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416 |
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417 |
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418 \begin{itemize} |
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419 \item \bl{$f(x)$} can be released, if \bl{$f$} is insensitive to |
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420 individual entries \bl{$x_1, \ldots, x_n$}\\ |
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421 \item Intuition: whatever is learned from the dataset would be learned regardless of whether |
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422 \bl{$x_i$} participates\bigskip\pause |
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423 |
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424 \item Noised needed in order to prevent:\\ Christian's salary $=$ |
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425 \begin{center} |
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426 \bl{\large$\Sigma$} all staff $-$ \bl{\large$\Sigma$} all staff $\backslash$ Christian |
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427 \end{center} |
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428 \end{itemize} |
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429 |
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430 \end{frame}} |
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431 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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432 |
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433 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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434 \mode<presentation>{ |
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435 \begin{frame}[c] |
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436 \frametitle{Adding Noise} |
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437 |
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438 Adding noise is not as trivial as one would wish: |
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439 |
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440 \begin{itemize} |
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441 \item If I ask how many of three have seen the Gangnam video and get a result |
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442 as follows |
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443 |
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444 \begin{center} |
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445 \begin{tabular}{l|c} |
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446 Alice & yes\\ |
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447 Bob & no\\ |
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448 Charlie & yes\\ |
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449 \end{tabular} |
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450 \end{center} |
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451 |
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452 then I have to add a noise of \bl{$1$}. So answers would be in the |
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453 range of \bl{$1$} to \bl{$3$} |
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454 |
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455 \bigskip |
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456 \item But if I ask five questions for all the dataset (has seen Gangnam video, is male, below 30, \ldots), |
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457 then one individual can change the dataset by \bl{$5$} |
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458 \end{itemize} |
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459 |
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460 \end{frame}} |
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461 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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462 |
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463 |
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464 |
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465 |
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466 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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467 \mode<presentation>{ |
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468 \begin{frame}[c] |
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469 \frametitle{\begin{tabular}{@{}c@{}}Tor, Anonymous Webbrowsing\end{tabular}} |
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470 |
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471 \begin{itemize} |
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472 \item initially developed by US Navy Labs, but then opened up to the world |
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473 \item network of proxy notes |
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474 \end{itemize} |
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475 |
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476 \end{frame}} |
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477 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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478 |
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479 |
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480 |
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481 |
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482 \end{document} |
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483 |
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484 %%% Local Variables: |
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485 %%% mode: latex |
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486 %%% TeX-master: t |
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487 %%% End: |
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488 |