<story><title>Apple and Google partner on Covid-19 contact tracing technology</title><url>https://www.apple.com/newsroom/2020/04/apple-and-google-partner-on-covid-19-contact-tracing-technology/</url></story><parent_chain><item><author>The_Double</author><text>There is surprisingly little discussion about the actual spec here. It looks really good to me!&lt;p&gt;- Advertisements change every 15 minutes, are not trackable unless keys are shared.&lt;p&gt;- The only central bit is a repository of &amp;quot;infected&amp;quot; daily keys.&lt;p&gt;- No knowledge about contacts is shared with a central authority.&lt;p&gt;Nothing is shared unless you are infected and decide to share your keys, which are only valid for one day. I don&amp;#x27;t see how you could have a real argument against this unless you are a privacy extremist. It also seems more privacy friendly than the Singapore or German apps.</text></item></parent_chain><comment><author>jka</author><text>In widely distributed and important spec like this it may be useful to look for what is conspicuously absent or unstated, rather than simply reading the precise positive language.&lt;p&gt;To my mind this phrase under &amp;#x27;Privacy Considerations&amp;#x27; in the Cryptography Specification stands out:&lt;p&gt;&amp;quot;A server operator implementing this protocol does not learn who users have been in proximity with or users’ location unless it also has the unlikely capability to scan advertisements from users who recently reported Diagnosis Keys.&amp;quot;&lt;p&gt;That phrase explicitly mentions that &lt;i&gt;server operators&lt;/i&gt; cannot learn about user proximities.&lt;p&gt;What I reckon may be unstated there is that it could be possible for adversaries with sidechannel &amp;#x2F; network monitoring capability to learn those kind of details about users (i.e. internet, cell data, and other data network operators).&lt;p&gt;If such a side door did exist, it would seem in the public interest to be aware of the scope of the availability of that data, especially given the potential (physical, social) vulnerability and risk of those users.&lt;p&gt;I&amp;#x27;d also like to be proven wrong about the possibility of such sidechannel attacks by anyone who understands the spec in more detail.&lt;p&gt;[1] - &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;covid19-static.cdn-apple.com&amp;#x2F;applications&amp;#x2F;covid19&amp;#x2F;current&amp;#x2F;static&amp;#x2F;contact-tracing&amp;#x2F;pdf&amp;#x2F;ContactTracing-CryptographySpecification.pdf&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;covid19-static.cdn-apple.com&amp;#x2F;applications&amp;#x2F;covid19&amp;#x2F;cu...&lt;/a&gt;</text></comment>
<story><title>Apple and Google partner on Covid-19 contact tracing technology</title><url>https://www.apple.com/newsroom/2020/04/apple-and-google-partner-on-covid-19-contact-tracing-technology/</url></story><parent_chain><item><author>The_Double</author><text>There is surprisingly little discussion about the actual spec here. It looks really good to me!&lt;p&gt;- Advertisements change every 15 minutes, are not trackable unless keys are shared.&lt;p&gt;- The only central bit is a repository of &amp;quot;infected&amp;quot; daily keys.&lt;p&gt;- No knowledge about contacts is shared with a central authority.&lt;p&gt;Nothing is shared unless you are infected and decide to share your keys, which are only valid for one day. I don&amp;#x27;t see how you could have a real argument against this unless you are a privacy extremist. It also seems more privacy friendly than the Singapore or German apps.</text></item></parent_chain><comment><author>FartyMcFarter</author><text>&amp;gt;  I don&amp;#x27;t see how you could have a real argument against this unless you are a privacy extremist.&lt;p&gt;The authors of DP-3T (which seems quite similar to this spec) have a huge list of privacy caveats in their whitepaper [1], in section &amp;quot;5.4 Summary of centralised&amp;#x2F;decentralised design trade-offs&amp;quot;.&lt;p&gt;I haven&amp;#x27;t seen any analysis on how the Apple&amp;#x2F;Google spec prevents those problems.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;github.com&amp;#x2F;DP-3T&amp;#x2F;documents&amp;#x2F;raw&amp;#x2F;master&amp;#x2F;DP3T%20White%20Paper.pdf&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;github.com&amp;#x2F;DP-3T&amp;#x2F;documents&amp;#x2F;raw&amp;#x2F;master&amp;#x2F;DP3T%20White%2...&lt;/a&gt;</text></comment>