<!doctype html><!-- This is a valid HTML5 document. --> | |||||
<!-- Screen readers, SEO, extensions and so on. --> | |||||
<html lang="fr"> | |||||
<!-- Has to be within the first 1024 bytes, hence before the <title> | |||||
See: https://www.w3.org/TR/2012/CR-html5-20121217/document-metadata.html#charset --> | |||||
<meta charset="utf-8"> | |||||
<!-- Why no `X-UA-Compatible` meta: https://stackoverflow.com/a/6771584 --> | |||||
<!-- The viewport meta is quite crowded and we are responsible for that. | |||||
See: https://codepen.io/tigt/post/meta-viewport-for-2015 --> | |||||
<meta name="viewport" content="width=device-width,initial-scale=1"> | |||||
<!-- Required to make a valid HTML5 document. --> | |||||
<title>Temporary Contact Number based Contact Tracing (archive) — David Larlet</title> | |||||
<!-- Generated from https://realfavicongenerator.net/ such a mess. --> | |||||
<link rel="apple-touch-icon" sizes="180x180" href="/static/david/icons2/apple-touch-icon.png"> | |||||
<link rel="icon" type="image/png" sizes="32x32" href="/static/david/icons2/favicon-32x32.png"> | |||||
<link rel="icon" type="image/png" sizes="16x16" href="/static/david/icons2/favicon-16x16.png"> | |||||
<link rel="manifest" href="/static/david/icons2/site.webmanifest"> | |||||
<link rel="mask-icon" href="/static/david/icons2/safari-pinned-tab.svg" color="#07486c"> | |||||
<link rel="shortcut icon" href="/static/david/icons2/favicon.ico"> | |||||
<meta name="msapplication-TileColor" content="#f0f0ea"> | |||||
<meta name="msapplication-config" content="/static/david/icons2/browserconfig.xml"> | |||||
<meta name="theme-color" content="#f0f0ea"> | |||||
<!-- Thank you Florens! --> | |||||
<link rel="stylesheet" href="/static/david/css/style_2020-02-24.css"> | |||||
<!-- See https://www.zachleat.com/web/comprehensive-webfonts/ for the trade-off. --> | |||||
<link rel="preload" href="/static/david/css/fonts/triplicate_t4_poly_regular.woff2" as="font" type="font/woff2" crossorigin> | |||||
<link rel="preload" href="/static/david/css/fonts/triplicate_t4_poly_bold.woff2" as="font" type="font/woff2" crossorigin> | |||||
<link rel="preload" href="/static/david/css/fonts/triplicate_t4_poly_italic.woff2" as="font" type="font/woff2" crossorigin> | |||||
<meta name="robots" content="noindex, nofollow"> | |||||
<meta content="origin-when-cross-origin" name="referrer"> | |||||
<!-- Canonical URL for SEO purposes --> | |||||
<link rel="canonical" href="https://lucumr.pocoo.org/2020/4/9/tcn-contact-tracing/"> | |||||
<body class="remarkdown h1-underline h2-underline h3-underline hr-center ul-star pre-tick"> | |||||
<article> | |||||
<h1>Temporary Contact Number based Contact Tracing</h1> | |||||
<h2><a href="https://lucumr.pocoo.org/2020/4/9/tcn-contact-tracing/">Source originale du contenu</a></h2> | |||||
<p class="date">written on Thursday, April 9, 2020 | |||||
</p> | |||||
<p>I have already talked here before about <a class="reference external" href="https://lucumr.pocoo.org/2020/4/3/contact-tracing/">privacy preserving contact | |||||
tracing</a> to fight Covid-19 but I figured I | |||||
give an update to this. I have spent the last week now investigating | |||||
different approaches to this and my view has changed quite a bit.</p> | |||||
<p>I strongly believe that contact tracing through phone apps is one of our | |||||
best chances to return to normal and without losing our civil liberties. | |||||
If you want to understand why, have a look at <a class="reference external" href="https://lucumr.pocoo.org/2020/4/3/contact-tracing/">previous post about this | |||||
topic</a>.</p> | |||||
<div class="section" id="two-fundamental-approaches"> | |||||
<h2>Two Fundamental Approaches</h2> | |||||
<p>In the previous post I talked in favour of a partially centralized | |||||
approach. This was largely because I felt that one of the inherent | |||||
problems of any privacy preserving contact tracing system could be | |||||
somewhat mitigated. That downside is that a person could always use any | |||||
such contact tracing system in a way where they could determine that | |||||
another person they met tested positive for covid-19 later. With a | |||||
system that has support from a central authority this still cannot be | |||||
prevented, but such behavior could be detected as abusive. However I am | |||||
not quite convinced that this would just be security by obscurity and that | |||||
the more correct way to deal with this is to just fundamentally | |||||
communicate to users that this is an inherent property of the system.</p> | |||||
<p>So the disclaimer to any app has to be: if you do not want that other | |||||
people discover when you will test positive for covid-19 you should not | |||||
use any contact tracing apps. Which is also why I strongly believe that | |||||
any such system absolutely needs to be voluntary.</p> | |||||
<p>So if I no longer believe in favour of the centralized approach, what do I | |||||
prefer then? Quite simply put an approach based on temporary contact | |||||
numbers, short <a class="reference external" href="https://tcn-coalition.org/">TCNs</a>. These protocols are | |||||
fundamentally decentralized and give us some other benefits.</p> | |||||
</div> | |||||
<div class="section" id="reality-on-the-ground"> | |||||
<h2>Reality on the Ground</h2> | |||||
<p>What makes application based contact tracing very interesting is that they | |||||
take advantage of working on top of a widely deployed piece of hardware: | |||||
smart phones. Specifically smartphones which support Bluetooth low | |||||
energy (BLE). If you hold an AirPods case close to your iPhone you will | |||||
notice that something happens on your screen. BLE is what enables that.</p> | |||||
<p>The downside of this is that BLE comes with some restrictions. The two | |||||
most relevant ones are the payload size. BLE comes with different modes | |||||
and different platforms call this in different ways but the most | |||||
compatible and energy preserving modes restrict us to under 30 bytes of | |||||
payload. That's not enough to make fancy public key cryptography work | |||||
which would be necessary for centralized approaches to play to their | |||||
advantages. This is also why systems that currently follow the | |||||
centralized approach will typically exchange a short ID and the extra | |||||
payload is then actually exchanged through the cloud or <a class="reference external" href="https://en.wikipedia.org/wiki/Bluetooth_Low_Energy#GATT_operations">GATT</a>. | |||||
The former makes a system that could be somewhat decentralized much more | |||||
centralized.</p> | |||||
<p>TCN based protocols instead will exchange just random identifiers instead. | |||||
Most TCN based protocols currently suggest between 16 and 26 bytes of | |||||
effectively random data which is easier to work with.</p> | |||||
<p>Another complexity is that at present iOS devices in background cannot | |||||
discover each other. This limitation might be solvable by Apple and it | |||||
appears various groups are currently in contact with Apple to see what can | |||||
be done. Interestingly an iOS device with the app in background can be | |||||
discovered by an Android device so there might be a way to fix this.</p> | |||||
</div> | |||||
<div class="section" id="tcn-strawman-protocol"> | |||||
<h2>TCN Strawman Protocol</h2> | |||||
<p>The TCN strawman protocol is the most basic of all these protocols. It | |||||
was first written down by the <a class="reference external" href="https://www.coepi.org/">Co-Epi project</a> | |||||
and is very easy to explain.</p> | |||||
<ol class="arabic simple"> | |||||
<li>all mobile phones randomly generate TCNs and remember and broadcast | |||||
these.</li> | |||||
<li>all mobile phones check against a server which publishes TCNs that are | |||||
known to be covid-19 positive.</li> | |||||
<li>all mobile phones check their local contact list against the downloaded | |||||
list locally for an intersection.</li> | |||||
</ol> | |||||
<p>Step 2 is the only one where a central system is necessary. For instance | |||||
this could be the server of the Austrian Red Cross which publishes TCNs. | |||||
Since the TCNs of encounters are only stored on the devices they have to | |||||
get on contact with covid-19 tested positive individuals first.</p> | |||||
<p>The strawman protocol wouldn't work in practice at the peak of the | |||||
infection because of the sheer data requirements. However there are | |||||
various cryptographic tricks which are floating around to reduce the size | |||||
of the data set.</p> | |||||
</div> | |||||
<div class="section" id="dp-3t"> | |||||
<h2>DP-3T</h2> | |||||
<p><a class="reference external" href="https://github.com/DP-3T/documents/">DP-3T</a> is currently one of the | |||||
most promising protocols here. It has a low cost variant which satisfies | |||||
most of the qualities of the strawman protocol while reducing the amount | |||||
of data greatly (to around 1.5MB of data per day for a peak infection rate | |||||
of 40.000 infections a day). Additionally it comes with a protocol | |||||
extension (âUnlinkable decentralized proximity tracingâ) which improves on | |||||
the simple protocol in a few important aspects. Specifically it makes it | |||||
significantly harder for an adversary to track or identify infected users | |||||
at the cost of higher bandwidth requirements.</p> | |||||
<p>A simple version of the protocol is easily explained:</p> | |||||
<ol class="arabic simple"> | |||||
<li>A device generates a secret key. Each day the user derives a new | |||||
version of the secret key by feeding it into a ratchet like a SHA256 | |||||
hash function.</li> | |||||
<li>Each day the device generates TCNs out of the day's secret key for | |||||
instance by using a AES in counter mode. If for instance we want to | |||||
switch TCNs every 15 minutes we would need to generate 4 * 24 * 16 bytes | |||||
worth of TCNs to have enough for a day.</li> | |||||
<li>Devices now broadcast a random TCN for the day for 15 minutes each.</li> | |||||
<li>When a device encounters another person and they consider the contact | |||||
long enough, they record the approximate time of day and the TCN | |||||
encountered.</li> | |||||
<li>When a user tests covid-19 positive they upload the secret key of the | |||||
first day of infection and generate a new secret key.</li> | |||||
<li>Other devices now download the secret key for that user and generate | |||||
all possible TCNs locally and check for infection. They only need to | |||||
generate 14 derivations of the secret key and the 96 TCNs for each day.</li> | |||||
</ol> | |||||
<p>In the more complex version the device uploads seeds of the secret keys | |||||
for all time windows in the infection window. On the backend server a | |||||
<a class="reference external" href="https://en.wikipedia.org/wiki/Cuckoo_filter">cuckoo filter</a> is created | |||||
every 4 hours and the seeds are inserted. Because Cuckoo filters have a | |||||
small probability of producing false positives parameters need to be | |||||
selected appropriately to reduce this risk. The upside is that the sets | |||||
of identifiers used by the same user are hidden.</p> | |||||
</div> | |||||
<div class="section" id="pepp-pt-and-local-governments"> | |||||
<h2>PEPP-PT and Local Governments</h2> | |||||
<p>So this leads us to <a class="reference external" href="https://www.pepp-pt.org/">PEPP-PT</a>. It would | |||||
appear that PEPP-PT is evaluating DP-3T as the reference protocol and | |||||
they are going to open source the code with the idea to support local | |||||
authorities in implementing their own version. Officially they have not | |||||
decided between centralized or TCN approaches yet, but there seems to be a | |||||
high chance it will be the latter. The concept is also very simple. | |||||
Simple enough that if you want to explain this system to others, there is | |||||
also a nice little <a class="reference external" href="https://ncase.me/contact-tracing/">comic strip available</a> that explains it.</p> | |||||
<p>If your local government is planning on implementing a covid tracing app | |||||
it might be worth directing them towards <a class="reference external" href="https://github.com/Co-Epi">Co-Epi</a>. It already has an implementation | |||||
of many of the same ideas in their GitHub repository. If they do want a | |||||
centralized approach the Singaporean government Open Sourced their | |||||
application under GPL3 under the name <a class="reference external" href="https://bluetrace.io/">BlueTrace</a>. It avoids largely unnecessary cloud | |||||
infrastructure from what I can tell.</p> | |||||
</div> | |||||
</article> | |||||
<hr> | |||||
<footer> | |||||
<p> | |||||
<a href="/david/" title="Aller à l’accueil">🏠</a> • | |||||
<a href="/david/log/" title="Accès au flux RSS">🤖</a> • | |||||
<a href="http://larlet.com" title="Go to my English profile" data-instant>🇨🇦</a> • | |||||
<a href="mailto:david%40larlet.fr" title="Envoyer un courriel">📮</a> • | |||||
<abbr title="Hébergeur : Alwaysdata, 62 rue Tiquetonne 75002 Paris, +33184162340">🧚</abbr> | |||||
</p> | |||||
</footer> | |||||
<script src="/static/david/js/instantpage-3.0.0.min.js" type="module" defer></script> | |||||
</body> | |||||
</html> |
title: Temporary Contact Number based Contact Tracing | |||||
url: https://lucumr.pocoo.org/2020/4/9/tcn-contact-tracing/ | |||||
hash_url: 7f71531b565d7a8b0a99100786687cfd | |||||
<p class="date">written on Thursday, April 9, 2020 | |||||
</p><p>I have already talked here before about <a class="reference external" href="https://lucumr.pocoo.org/2020/4/3/contact-tracing/">privacy preserving contact | |||||
tracing</a> to fight Covid-19 but I figured I | |||||
give an update to this. I have spent the last week now investigating | |||||
different approaches to this and my view has changed quite a bit.</p> | |||||
<p>I strongly believe that contact tracing through phone apps is one of our | |||||
best chances to return to normal and without losing our civil liberties. | |||||
If you want to understand why, have a look at <a class="reference external" href="https://lucumr.pocoo.org/2020/4/3/contact-tracing/">previous post about this | |||||
topic</a>.</p> | |||||
<div class="section" id="two-fundamental-approaches"> | |||||
<h2>Two Fundamental Approaches</h2> | |||||
<p>In the previous post I talked in favour of a partially centralized | |||||
approach. This was largely because I felt that one of the inherent | |||||
problems of any privacy preserving contact tracing system could be | |||||
somewhat mitigated. That downside is that a person could always use any | |||||
such contact tracing system in a way where they could determine that | |||||
another person they met tested positive for covid-19 later. With a | |||||
system that has support from a central authority this still cannot be | |||||
prevented, but such behavior could be detected as abusive. However I am | |||||
not quite convinced that this would just be security by obscurity and that | |||||
the more correct way to deal with this is to just fundamentally | |||||
communicate to users that this is an inherent property of the system.</p> | |||||
<p>So the disclaimer to any app has to be: if you do not want that other | |||||
people discover when you will test positive for covid-19 you should not | |||||
use any contact tracing apps. Which is also why I strongly believe that | |||||
any such system absolutely needs to be voluntary.</p> | |||||
<p>So if I no longer believe in favour of the centralized approach, what do I | |||||
prefer then? Quite simply put an approach based on temporary contact | |||||
numbers, short <a class="reference external" href="https://tcn-coalition.org/">TCNs</a>. These protocols are | |||||
fundamentally decentralized and give us some other benefits.</p> | |||||
</div> | |||||
<div class="section" id="reality-on-the-ground"> | |||||
<h2>Reality on the Ground</h2> | |||||
<p>What makes application based contact tracing very interesting is that they | |||||
take advantage of working on top of a widely deployed piece of hardware: | |||||
smart phones. Specifically smartphones which support Bluetooth low | |||||
energy (BLE). If you hold an AirPods case close to your iPhone you will | |||||
notice that something happens on your screen. BLE is what enables that.</p> | |||||
<p>The downside of this is that BLE comes with some restrictions. The two | |||||
most relevant ones are the payload size. BLE comes with different modes | |||||
and different platforms call this in different ways but the most | |||||
compatible and energy preserving modes restrict us to under 30 bytes of | |||||
payload. That's not enough to make fancy public key cryptography work | |||||
which would be necessary for centralized approaches to play to their | |||||
advantages. This is also why systems that currently follow the | |||||
centralized approach will typically exchange a short ID and the extra | |||||
payload is then actually exchanged through the cloud or <a class="reference external" href="https://en.wikipedia.org/wiki/Bluetooth_Low_Energy#GATT_operations">GATT</a>. | |||||
The former makes a system that could be somewhat decentralized much more | |||||
centralized.</p> | |||||
<p>TCN based protocols instead will exchange just random identifiers instead. | |||||
Most TCN based protocols currently suggest between 16 and 26 bytes of | |||||
effectively random data which is easier to work with.</p> | |||||
<p>Another complexity is that at present iOS devices in background cannot | |||||
discover each other. This limitation might be solvable by Apple and it | |||||
appears various groups are currently in contact with Apple to see what can | |||||
be done. Interestingly an iOS device with the app in background can be | |||||
discovered by an Android device so there might be a way to fix this.</p> | |||||
</div> | |||||
<div class="section" id="tcn-strawman-protocol"> | |||||
<h2>TCN Strawman Protocol</h2> | |||||
<p>The TCN strawman protocol is the most basic of all these protocols. It | |||||
was first written down by the <a class="reference external" href="https://www.coepi.org/">Co-Epi project</a> | |||||
and is very easy to explain.</p> | |||||
<ol class="arabic simple"> | |||||
<li>all mobile phones randomly generate TCNs and remember and broadcast | |||||
these.</li> | |||||
<li>all mobile phones check against a server which publishes TCNs that are | |||||
known to be covid-19 positive.</li> | |||||
<li>all mobile phones check their local contact list against the downloaded | |||||
list locally for an intersection.</li> | |||||
</ol> | |||||
<p>Step 2 is the only one where a central system is necessary. For instance | |||||
this could be the server of the Austrian Red Cross which publishes TCNs. | |||||
Since the TCNs of encounters are only stored on the devices they have to | |||||
get on contact with covid-19 tested positive individuals first.</p> | |||||
<p>The strawman protocol wouldn't work in practice at the peak of the | |||||
infection because of the sheer data requirements. However there are | |||||
various cryptographic tricks which are floating around to reduce the size | |||||
of the data set.</p> | |||||
</div> | |||||
<div class="section" id="dp-3t"> | |||||
<h2>DP-3T</h2> | |||||
<p><a class="reference external" href="https://github.com/DP-3T/documents/">DP-3T</a> is currently one of the | |||||
most promising protocols here. It has a low cost variant which satisfies | |||||
most of the qualities of the strawman protocol while reducing the amount | |||||
of data greatly (to around 1.5MB of data per day for a peak infection rate | |||||
of 40.000 infections a day). Additionally it comes with a protocol | |||||
extension (âUnlinkable decentralized proximity tracingâ) which improves on | |||||
the simple protocol in a few important aspects. Specifically it makes it | |||||
significantly harder for an adversary to track or identify infected users | |||||
at the cost of higher bandwidth requirements.</p> | |||||
<p>A simple version of the protocol is easily explained:</p> | |||||
<ol class="arabic simple"> | |||||
<li>A device generates a secret key. Each day the user derives a new | |||||
version of the secret key by feeding it into a ratchet like a SHA256 | |||||
hash function.</li> | |||||
<li>Each day the device generates TCNs out of the day's secret key for | |||||
instance by using a AES in counter mode. If for instance we want to | |||||
switch TCNs every 15 minutes we would need to generate 4 * 24 * 16 bytes | |||||
worth of TCNs to have enough for a day.</li> | |||||
<li>Devices now broadcast a random TCN for the day for 15 minutes each.</li> | |||||
<li>When a device encounters another person and they consider the contact | |||||
long enough, they record the approximate time of day and the TCN | |||||
encountered.</li> | |||||
<li>When a user tests covid-19 positive they upload the secret key of the | |||||
first day of infection and generate a new secret key.</li> | |||||
<li>Other devices now download the secret key for that user and generate | |||||
all possible TCNs locally and check for infection. They only need to | |||||
generate 14 derivations of the secret key and the 96 TCNs for each day.</li> | |||||
</ol> | |||||
<p>In the more complex version the device uploads seeds of the secret keys | |||||
for all time windows in the infection window. On the backend server a | |||||
<a class="reference external" href="https://en.wikipedia.org/wiki/Cuckoo_filter">cuckoo filter</a> is created | |||||
every 4 hours and the seeds are inserted. Because Cuckoo filters have a | |||||
small probability of producing false positives parameters need to be | |||||
selected appropriately to reduce this risk. The upside is that the sets | |||||
of identifiers used by the same user are hidden.</p> | |||||
</div> | |||||
<div class="section" id="pepp-pt-and-local-governments"> | |||||
<h2>PEPP-PT and Local Governments</h2> | |||||
<p>So this leads us to <a class="reference external" href="https://www.pepp-pt.org/">PEPP-PT</a>. It would | |||||
appear that PEPP-PT is evaluating DP-3T as the reference protocol and | |||||
they are going to open source the code with the idea to support local | |||||
authorities in implementing their own version. Officially they have not | |||||
decided between centralized or TCN approaches yet, but there seems to be a | |||||
high chance it will be the latter. The concept is also very simple. | |||||
Simple enough that if you want to explain this system to others, there is | |||||
also a nice little <a class="reference external" href="https://ncase.me/contact-tracing/">comic strip available</a> that explains it.</p> | |||||
<p>If your local government is planning on implementing a covid tracing app | |||||
it might be worth directing them towards <a class="reference external" href="https://github.com/Co-Epi">Co-Epi</a>. It already has an implementation | |||||
of many of the same ideas in their GitHub repository. If they do want a | |||||
centralized approach the Singaporean government Open Sourced their | |||||
application under GPL3 under the name <a class="reference external" href="https://bluetrace.io/">BlueTrace</a>. It avoids largely unnecessary cloud | |||||
infrastructure from what I can tell.</p> | |||||
</div> |
<!doctype html><!-- This is a valid HTML5 document. --> | |||||
<!-- Screen readers, SEO, extensions and so on. --> | |||||
<html lang="fr"> | |||||
<!-- Has to be within the first 1024 bytes, hence before the <title> | |||||
See: https://www.w3.org/TR/2012/CR-html5-20121217/document-metadata.html#charset --> | |||||
<meta charset="utf-8"> | |||||
<!-- Why no `X-UA-Compatible` meta: https://stackoverflow.com/a/6771584 --> | |||||
<!-- The viewport meta is quite crowded and we are responsible for that. | |||||
See: https://codepen.io/tigt/post/meta-viewport-for-2015 --> | |||||
<meta name="viewport" content="width=device-width,initial-scale=1"> | |||||
<!-- Required to make a valid HTML5 document. --> | |||||
<title>How Contact Tracing Can Foil COVID-19 & Big Brother (archive) — David Larlet</title> | |||||
<!-- Generated from https://realfavicongenerator.net/ such a mess. --> | |||||
<link rel="apple-touch-icon" sizes="180x180" href="/static/david/icons2/apple-touch-icon.png"> | |||||
<link rel="icon" type="image/png" sizes="32x32" href="/static/david/icons2/favicon-32x32.png"> | |||||
<link rel="icon" type="image/png" sizes="16x16" href="/static/david/icons2/favicon-16x16.png"> | |||||
<link rel="manifest" href="/static/david/icons2/site.webmanifest"> | |||||
<link rel="mask-icon" href="/static/david/icons2/safari-pinned-tab.svg" color="#07486c"> | |||||
<link rel="shortcut icon" href="/static/david/icons2/favicon.ico"> | |||||
<meta name="msapplication-TileColor" content="#f0f0ea"> | |||||
<meta name="msapplication-config" content="/static/david/icons2/browserconfig.xml"> | |||||
<meta name="theme-color" content="#f0f0ea"> | |||||
<!-- Thank you Florens! --> | |||||
<link rel="stylesheet" href="/static/david/css/style_2020-02-24.css"> | |||||
<!-- See https://www.zachleat.com/web/comprehensive-webfonts/ for the trade-off. --> | |||||
<link rel="preload" href="/static/david/css/fonts/triplicate_t4_poly_regular.woff2" as="font" type="font/woff2" crossorigin> | |||||
<link rel="preload" href="/static/david/css/fonts/triplicate_t4_poly_bold.woff2" as="font" type="font/woff2" crossorigin> | |||||
<link rel="preload" href="/static/david/css/fonts/triplicate_t4_poly_italic.woff2" as="font" type="font/woff2" crossorigin> | |||||
<meta name="robots" content="noindex, nofollow"> | |||||
<meta content="origin-when-cross-origin" name="referrer"> | |||||
<!-- Canonical URL for SEO purposes --> | |||||
<link rel="canonical" href="https://ncase.me/contact-tracing/"> | |||||
<body class="remarkdown h1-underline h2-underline h3-underline hr-center ul-star pre-tick"> | |||||
<article> | |||||
<h1>How Contact Tracing Can Foil COVID-19 & Big Brother</h1> | |||||
<h2><a href="https://ncase.me/contact-tracing/">Source originale du contenu</a></h2> | |||||
<p> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0001.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0002.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0003.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0004.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0005.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0006.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0007.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0008.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0009.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0010.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0011.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0012.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0013.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0014.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0015.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0016.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0017.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0018.png?v=3"/> | |||||
</p> | |||||
<p> | |||||
<a href="https://ncase.me/contact-tracing/comic.zip">Download this comic as a .zip!</a> | |||||
</p> | |||||
<p> | |||||
Sources: | |||||
<a href="https://github.com/DP-3T/documents">DP-3T</a>, | |||||
<a href="https://github.com/TCNCoalition/TCN">TCN Protocol</a>, | |||||
<a href="https://science.sciencemag.org/content/early/2020/03/30/science.abb6936">Ferretti & Wymant et al</a> | |||||
</p> | |||||
<p> | |||||
<a href="https://creativecommons.org/publicdomain/zero/1.0/deed.en">CC0/Public Domain</a> | |||||
</p> | |||||
<p> | |||||
By Nicky Case | |||||
(<a href="https://ncase.me/">site</a> · | |||||
<a href="https://www.patreon.com/ncase">patreon</a>) | |||||
</p> | |||||
<p> | |||||
With huge help from | |||||
<a href="http://carmelatroncoso.com/">Prof Carmelo Troncoso</a> & | |||||
<a href="https://people.epfl.ch/marcel.salathe">Prof Marcel Salathé</a> | |||||
</p> | |||||
</article> | |||||
<hr> | |||||
<footer> | |||||
<p> | |||||
<a href="/david/" title="Aller à l’accueil">🏠</a> • | |||||
<a href="/david/log/" title="Accès au flux RSS">🤖</a> • | |||||
<a href="http://larlet.com" title="Go to my English profile" data-instant>🇨🇦</a> • | |||||
<a href="mailto:david%40larlet.fr" title="Envoyer un courriel">📮</a> • | |||||
<abbr title="Hébergeur : Alwaysdata, 62 rue Tiquetonne 75002 Paris, +33184162340">🧚</abbr> | |||||
</p> | |||||
</footer> | |||||
<script src="/static/david/js/instantpage-3.0.0.min.js" type="module" defer></script> | |||||
</body> | |||||
</html> |
title: How Contact Tracing Can Foil COVID-19 & Big Brother | |||||
url: https://ncase.me/contact-tracing/ | |||||
hash_url: c8a8edb7bc65f4ed6b0edc18010434cc | |||||
<p> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0001.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0002.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0003.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0004.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0005.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0006.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0007.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0008.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0009.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0010.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0011.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0012.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0013.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0014.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0015.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0016.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0017.png?v=3"/> | |||||
<img src="https://ncase.me/contact-tracing/panels/panel0018.png?v=3"/> | |||||
</p> | |||||
<p> | |||||
<a href="https://ncase.me/contact-tracing/comic.zip">Download this comic as a .zip!</a> | |||||
</p> | |||||
<p> | |||||
Sources: | |||||
<a href="https://github.com/DP-3T/documents">DP-3T</a>, | |||||
<a href="https://github.com/TCNCoalition/TCN">TCN Protocol</a>, | |||||
<a href="https://science.sciencemag.org/content/early/2020/03/30/science.abb6936">Ferretti & Wymant et al</a> | |||||
</p> | |||||
<p> | |||||
<a href="https://creativecommons.org/publicdomain/zero/1.0/deed.en">CC0/Public Domain</a> | |||||
</p> | |||||
<p> | |||||
By Nicky Case | |||||
(<a href="https://ncase.me/">site</a> · | |||||
<a href="https://www.patreon.com/ncase">patreon</a>) | |||||
</p> | |||||
<p> | |||||
With huge help from | |||||
<a href="http://carmelatroncoso.com/">Prof Carmelo Troncoso</a> & | |||||
<a href="https://people.epfl.ch/marcel.salathe">Prof Marcel Salathé</a> | |||||
</p> |
<li><a href="/david/cache/2020/99c5bddeed5760b748ba9b219270d75d/" title="Accès à l'article caché">Ecological crises and equitable futures</a> (<a href="https://esra.nz/ecological-crises-equitable-futures/" title="Accès à l'article original">original</a>)</li> | <li><a href="/david/cache/2020/99c5bddeed5760b748ba9b219270d75d/" title="Accès à l'article caché">Ecological crises and equitable futures</a> (<a href="https://esra.nz/ecological-crises-equitable-futures/" title="Accès à l'article original">original</a>)</li> | ||||
<li><a href="/david/cache/2020/7f71531b565d7a8b0a99100786687cfd/" title="Accès à l'article caché">Temporary Contact Number based Contact Tracing</a> (<a href="https://lucumr.pocoo.org/2020/4/9/tcn-contact-tracing/" title="Accès à l'article original">original</a>)</li> | |||||
<li><a href="/david/cache/2020/2c6ccd57b9f0f1c39706013d026de507/" title="Accès à l'article caché">L’affaire de la Ligue du LOL, ou la fabrique de l’oubli</a> (<a href="https://medium.com/@florence.porcel/laffaire-de-la-ligue-du-lol-ou-la-fabrique-de-l-oubli-df4ad3f5f2b5" title="Accès à l'article original">original</a>)</li> | <li><a href="/david/cache/2020/2c6ccd57b9f0f1c39706013d026de507/" title="Accès à l'article caché">L’affaire de la Ligue du LOL, ou la fabrique de l’oubli</a> (<a href="https://medium.com/@florence.porcel/laffaire-de-la-ligue-du-lol-ou-la-fabrique-de-l-oubli-df4ad3f5f2b5" title="Accès à l'article original">original</a>)</li> | ||||
<li><a href="/david/cache/2020/c8a8edb7bc65f4ed6b0edc18010434cc/" title="Accès à l'article caché">How Contact Tracing Can Foil COVID-19 & Big Brother</a> (<a href="https://ncase.me/contact-tracing/" title="Accès à l'article original">original</a>)</li> | |||||
<li><a href="/david/cache/2020/fc97310297178a549eab5c5f9e8a334f/" title="Accès à l'article caché">Why 543 KB keep me up at night</a> (<a href="https://www.matuzo.at/blog/why-543kb-keep-me-up-at-night/" title="Accès à l'article original">original</a>)</li> | <li><a href="/david/cache/2020/fc97310297178a549eab5c5f9e8a334f/" title="Accès à l'article caché">Why 543 KB keep me up at night</a> (<a href="https://www.matuzo.at/blog/why-543kb-keep-me-up-at-night/" title="Accès à l'article original">original</a>)</li> | ||||
<li><a href="/david/cache/2020/1d190443e06aa99b44dd2a4d55b1b58e/" title="Accès à l'article caché">The Secretive Company That Might End Privacy as We Know It</a> (<a href="https://www.nytimes.com/2020/01/18/technology/clearview-privacy-facial-recognition.html" title="Accès à l'article original">original</a>)</li> | <li><a href="/david/cache/2020/1d190443e06aa99b44dd2a4d55b1b58e/" title="Accès à l'article caché">The Secretive Company That Might End Privacy as We Know It</a> (<a href="https://www.nytimes.com/2020/01/18/technology/clearview-privacy-facial-recognition.html" title="Accès à l'article original">original</a>)</li> |