<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom" ><generator uri="https://jekyllrb.com/" version="4.4.1">Jekyll</generator><link href="/feed.xml" rel="self" type="application/atom+xml" /><link href="/" rel="alternate" type="text/html" /><updated>2026-07-10T18:34:44+00:00</updated><id>/feed.xml</id><title type="html">Cryptology and Data Security</title><subtitle>Cryptology and data security research group, Institute of Computer Science, University of Bern.</subtitle><author><name>Cryptology and Data Security Research Group</name></author><entry><title type="html">Crypto x AI Convergence</title><link href="/2026/06/08/aic3.html" rel="alternate" type="text/html" title="Crypto x AI Convergence" /><published>2026-06-08T00:00:00+00:00</published><updated>2026-06-08T00:00:00+00:00</updated><id>/2026/06/08/aic3</id><content type="html" xml:base="/2026/06/08/aic3.html"><![CDATA[<p>The <a href="//ic3research.org">Initiative for CryptoCurrencies and Contracts (IC3)</a>
analyzes how the convergence of two emerging technologies, crypto and AI, can
help or harm users in a new overview titled <a href="//aic3.io"><em>Crypto x AI, AI x Crypto: A Survey</em></a>.</p>

<p><a href="//aic3.io"><img src="/assets/img/crypto_x_ai.png" alt="Crypto x AI, AI x CRYPTO" width="80%" class="center-image" /></a></p>

<p>Over two dozen computer scientists and researchers from industry and academic
institutions including Cornell Tech, Carnegie Mellon University, Princeton
University, Technion, Yale University, and University of Bern have released
comprehensive research addressing the intersection of crypto and AI.</p>

<p>The survey published by IC3 serves as a guide for future research and
development, offering key insights into what crypto can do for AI and vice
versa, enumerating open problems, identifying security risks, new areas of
research, and common myths and misconceptions.</p>

<p>“There is a tremendous amount of material and papers in this space, both from
the research community and industry, and it can be difficult to make sense of
it all. Our goal with this survey was to highlight and summarize what we
currently know, and perhaps more importantly, surface gaps that the research
and practice communities can address,” said the survey’s co-editor Giulia
Fanti.</p>

<p>This survey offers a clear-eyed view of the opportunities and challenges of
crypto and AI. For example, AI could make blockchains more autonomous and
intelligent, but could also introduce new forms of market abuse and
collusion. Key findings include:</p>

<p>AI can make crypto more “usable and flexible.” Models can help blockchains
process real-world data, enhance analytics and fraud detection, improve smart
contract security, and execute tasks based on high-level human objectives.
AI-powered trading systems can enable collusion between autonomous agents and
create unfair insider advantages through opaque strategies.  Crypto tools and
infrastructure can create more secure and trustworthy data pipelines for AI
model training.  Although there is much excitement about decentralizing AI
pipelines—from training to inference to data sourcing and evaluation—there is
relatively little quantitative comparison showing if and how decentralization
helps end metrics, like costs to AI providers or users.</p>

<p>“Crypto is a ‘hard’ technology, built on cryptographic primitives with
rigorous security properties and programs that enforce unambiguous results. AI
is a ‘soft’ technology: No one fully understands or can fully trust the models
on which it depends. Combining the two naively can be like soldering Jell-O,”
said co-editor Ari Juels. “Combined well, though, crypto can channel AI’s
fluid power into secure and reliable systems. Our survey’s goal is to guide
the community toward the areas of promise—and there are a few—within the
crypto × AI vision.”</p>

<p>The survey outlines areas for future research and development, acting as an
essential guide for businesses and technologists. These insights are essential
for organizations looking to capitalize on new economic opportunities and
secure a competitive advantage, while actively identifying and mitigating
emerging threats.</p>

<p><a href="//aic3.io"><strong>Access the survey “Crypto x AI, AI x Crypto</strong></a>.</p>

<p>The CRYPTO group is a member of the <a href="//ic3research.org">Initiative for CryptoCurrencies and
Contracts (IC3)</a>); <a href="https://www.ziv.unibe.ch/ueber_uns/personen/personen_abt_prof_eggen/dr_iur_sillaber_christian/index_ger.html">Christian
Sillaber</a>
of the Institute for Civil Law as well as <a href="//crypto.unibe.ch/cc/">Christian
Cachin</a> contributed to the survey.</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[The Initiative for CryptoCurrencies and Contracts (IC3) analyzes how the convergence of two emerging technologies, crypto and AI, can help or harm users in a new overview titled Crypto x AI, AI x Crypto: A Survey.]]></summary></entry><entry><title type="html">Welcome Jonathan Bernhard</title><link href="/2026/04/14/jonathan.bernhard.html" rel="alternate" type="text/html" title="Welcome Jonathan Bernhard" /><published>2026-04-14T00:00:00+00:00</published><updated>2026-04-14T00:00:00+00:00</updated><id>/2026/04/14/jonathan.bernhard</id><content type="html" xml:base="/2026/04/14/jonathan.bernhard.html"><![CDATA[<p>In April 2026 <a href="/jb/">Jonathan Bernhard</a> has become a member of the CRYPTO
research group as a Ph.D. student.  He previously completed a M.Sc. in
Computer Science at the <a href="//www.unifr.ch/inf/">University of Fribourg</a> and in
the <a href="//mcs.unibnf.ch">Swiss Joint Master of Computer Science</a>, where he
already worked on his thesis with the group.  Welcome!</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[In April 2026 Jonathan Bernhard has become a member of the CRYPTO research group as a Ph.D. student. He previously completed a M.Sc. in Computer Science at the University of Fribourg and in the Swiss Joint Master of Computer Science, where he already worked on his thesis with the group. Welcome!]]></summary></entry><entry><title type="html">Digital Shaper 2026</title><link href="/2026/03/26/digital_shaper.html" rel="alternate" type="text/html" title="Digital Shaper 2026" /><published>2026-03-26T00:00:00+00:00</published><updated>2026-03-26T00:00:00+00:00</updated><id>/2026/03/26/digital_shaper</id><content type="html" xml:base="/2026/03/26/digital_shaper.html"><![CDATA[<p><a href="/cc/">Christian Cachin</a> has been named one of 100 <strong><a href="//www.bilanz.ch/digital-shapers/digital-shapers-2026-eine-neue-ara-der-digitalisierung/v952zld">Digital Shapers 2026</a></strong> by Bilanz, the biweekly Swiss business magazine.
The magazine recognized him in the category of <em>Defenders</em> for his research on <a href="//www.bilanz.ch/digital-shapers/digitale-koepfe-der-schweiz-defenders-digital-shapers-2026/34zfder">secure protocols for cryptocurrencies</a>.</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[Christian Cachin has been named one of 100 Digital Shapers 2026 by Bilanz, the biweekly Swiss business magazine. The magazine recognized him in the category of Defenders for his research on secure protocols for cryptocurrencies.]]></summary></entry><entry><title type="html">Welcome Ulysse Pavloff</title><link href="/2026/03/11/ulysse_pavloff.html" rel="alternate" type="text/html" title="Welcome Ulysse Pavloff" /><published>2026-03-11T00:00:00+00:00</published><updated>2026-03-11T00:00:00+00:00</updated><id>/2026/03/11/ulysse_pavloff</id><content type="html" xml:base="/2026/03/11/ulysse_pavloff.html"><![CDATA[<p><a href="/up/">Ulysse Pavloff</a> has joined the CRYPTO research group in March 2026 as a
postdoctoral researcher.  He completed his PhD in Computer Science at
Paris-Saclay University in 2024 and specializes in blockchain and game theory.
Welcome!</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[Ulysse Pavloff has joined the CRYPTO research group in March 2026 as a postdoctoral researcher. He completed his PhD in Computer Science at Paris-Saclay University in 2024 and specializes in blockchain and game theory. Welcome!]]></summary></entry><entry><title type="html">Workshop on Secure Systems</title><link href="/2026/01/16/workshop_secure_systems.html" rel="alternate" type="text/html" title="Workshop on Secure Systems" /><published>2026-01-16T00:00:00+00:00</published><updated>2026-01-16T00:00:00+00:00</updated><id>/2026/01/16/workshop_secure_systems</id><content type="html" xml:base="/2026/01/16/workshop_secure_systems.html"><![CDATA[<p>The <a href="//crypto.unibe.ch">Cryptology and Data Security Research Group</a> organizes
a workshop on the theme of <em>secure systems</em> :</p>

<h3 id="university-of-bern"><a href="//www.unibe.ch">University of Bern</a></h3>

<h3 id="16-february-2026">16 February 2026</h3>

<h3 id="hauptgebäude-hochschulstrasse-4-room-033"><a href="//www.unibe.ch/universitaet/campus__und__infrastruktur/lageplaene__und__hoerraeume/gebaeudeplaene/1_hauptgebaeude/index_ger.html">Hauptgebäude</a>, Hochschulstrasse 4, Room 033</h3>

<p><img src="/assets/img/unibe_hg_novembermorgen.jpg" alt="University of Bern" width="100%" class="center-image" /></p>

<table>
  <thead>
    <tr>
      <th style="text-align: right"> </th>
      <th>Schedule</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td style="text-align: right">9:30</td>
      <td><strong><a href="/cc">Christian Cachin</a></strong>, University of Bern</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td>Welcome</td>
    </tr>
    <tr>
      <td style="text-align: right">9:30-10:30</td>
      <td><strong><a href="//profiles.imperial.ac.uk/prp">Peter Pietzuch</a></strong>, Imperial College London</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td>Keynote: Improving Cloud Security with Hardware Memory Capabilities</td>
    </tr>
    <tr>
      <td style="text-align: right">10:30-10:50</td>
      <td>Break</td>
    </tr>
    <tr>
      <td style="text-align: right">11:00-11:30</td>
      <td><strong><a href="//crypto.unibe.ch/fxw">François-Xavier Wicht</a></strong>, University of Bern</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td>Censorship-Resistant BitTorrent Trackers</td>
    </tr>
    <tr>
      <td style="text-align: right">11:30-12:00</td>
      <td><a href="//www.unine.ch/iiun/presentation/equipe/"><strong>Mpoki Mwaisela</strong></a>, University of Neuchatel</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td>IM-PIR: In-Memory Private Information Retrieval</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td> </td>
    </tr>
    <tr>
      <td style="text-align: right">12:15-14:00</td>
      <td><strong>Lunch</strong> (details to be announced)</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td> </td>
    </tr>
    <tr>
      <td style="text-align: right">14:00-14:45</td>
      <td><strong><a href="//research.ibm.com/people/anil-kurmus">Anil Kurmus</a></strong>, IBM Research - Zurich</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td>Speculative Memory Errors</td>
    </tr>
    <tr>
      <td style="text-align: right">14:45-15:15</td>
      <td><a href="//www.unine.ch/iiun/presentation/equipe/"><strong>Louis Vialar</strong></a>, University of Neuchatel</td>
    </tr>
    <tr>
      <td style="text-align: right"> </td>
      <td>SECUREFUSION: A Versatile Proxy for Transparent DBMS Encryption</td>
    </tr>
  </tbody>
</table>

<h3 id="register-here-to-attend"><a href="https://forms.office.com/e/XBcEbCpmnE">Register here to attend</a></h3>

<h3 id="advance-registration-is-necessary-until-12-february-2026">Advance registration is necessary until 12 February 2026.</h3>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[The Cryptology and Data Security Research Group organizes a workshop on the theme of secure systems :]]></summary></entry><entry><title type="html">New results on asymmetric trust</title><link href="/2025/12/16/asymmetric_model.html" rel="alternate" type="text/html" title="New results on asymmetric trust" /><published>2025-12-16T00:00:00+00:00</published><updated>2025-12-16T00:00:00+00:00</updated><id>/2025/12/16/asymmetric_model</id><content type="html" xml:base="/2025/12/16/asymmetric_model.html"><![CDATA[<p>The <a href="//doi.org/10.1007/s00446-024-00469-1">asymmetric trust model</a> lets each
participant in a distributed system make its own trust assumptions about
others, captured by an asymmetric quorum system. This contrasts with ordinary,
<a href="//doi.org/10.1007/s004460050050">symmetric quorum systems</a> and threshold
models, where trust assumptions are uniformly shared among
participants. Fundamental problems like reliable broadcast and consensus are
unsolvable in the asymmetric model if quorum systems satisfy only the
classical properties of consistency and availability. Existing approaches
overcome this by introducing stronger assumptions.</p>

<p>In <a href="//doi.org/10.48550/arXiv.2509.09493">recent work</a> that was published at
the <a href="//conferences.info.uaic.ro/opodis2025/">OPODIS 2025 conference</a>, CRYPTO
team member <a href="/jv/">Juan Villacis</a> with coauthors <a href="//iamores.github.io/">Ignacio Amores
Sesar</a> from the University of Aarhus and Simon Holmgaard
Kamp of Ruhr-Universität Bochum have shown that some of these assumptions are
overly restrictive, so much so that they effectively eliminate the benefits of
asymmetric trust. To address this, they have proposed a new approach to
characterize asymmetric problems and, building upon it, they introduce
algorithms for reliable broadcast and consensus that require weaker
assumptions than previous solutions.</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[The asymmetric trust model lets each participant in a distributed system make its own trust assumptions about others, captured by an asymmetric quorum system. This contrasts with ordinary, symmetric quorum systems and threshold models, where trust assumptions are uniformly shared among participants. Fundamental problems like reliable broadcast and consensus are unsolvable in the asymmetric model if quorum systems satisfy only the classical properties of consistency and availability. Existing approaches overcome this by introducing stronger assumptions.]]></summary></entry><entry><title type="html">Ph.D. degree for David Lehnherr</title><link href="/2025/12/10/phd-david.html" rel="alternate" type="text/html" title="Ph.D. degree for David Lehnherr" /><published>2025-12-10T00:00:00+00:00</published><updated>2025-12-10T00:00:00+00:00</updated><id>/2025/12/10/phd-david</id><content type="html" xml:base="/2025/12/10/phd-david.html"><![CDATA[<p><a href="/dl/">David Lehnherr</a> has successfully defended his Ph.D. thesis on 8 December 2025; the thesis is titled “Simplicial Structures for Epistemic Reasoning in Multi-agent Systems”. As the title reveals, this work is truly interdisciplinary and relates to logic and to distributed computing, spanning the fields between the research groups on <a href="//www.inf.unibe.ch/research/ltg/index_eng.html">Logic and Theory</a> and <a href="//crypto.unibe.ch/">Distributed Computing and Cryptography</a>.</p>

<p>As external examiner <a href="//sites.google.com/site/hansvanditmarsch/">Hans van Ditmarsch</a> joined from CNRS, IRIT, University of Toulouse.</p>

<p>Congratulations!</p>

<p><img src="/assets/img/phd-2025-david.jpg" alt="David, Hans, Thomas, Christian" width="80%" class="center-image" /></p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[David Lehnherr has successfully defended his Ph.D. thesis on 8 December 2025; the thesis is titled “Simplicial Structures for Epistemic Reasoning in Multi-agent Systems”. As the title reveals, this work is truly interdisciplinary and relates to logic and to distributed computing, spanning the fields between the research groups on Logic and Theory and Distributed Computing and Cryptography.]]></summary></entry><entry><title type="html">Scaling privacy-preserving cryptocurrencies with toxic decoys</title><link href="/2025/07/11/decoys.html" rel="alternate" type="text/html" title="Scaling privacy-preserving cryptocurrencies with toxic decoys" /><published>2025-07-11T00:00:00+00:00</published><updated>2025-07-11T00:00:00+00:00</updated><id>/2025/07/11/decoys</id><content type="html" xml:base="/2025/07/11/decoys.html"><![CDATA[<p>The research paper <a href="//eprint.iacr.org/2025/1124">Toxic Decoys: A Path to Scaling Privacy-Preserving
Cryptocurrencies</a> has been accepted for
publication in the <a href="//petsymposium.org">Proceedings on Privacy Enhancing Technologies
(PoPETs)</a> and will be presented at corresponding
symposium, <a href="//petsymposium.org/2025/">PETS 2025</a>, which takes place in
Washington, DC, from July 14-19, 2025.</p>

<p>This work tackles the ever-growing storage demands of anonymous
cryptocurrencies. It introduces a new scheme that randomly partitions the
fresh outputs of transactions into fixed-size bins. Subsequent transactions
reference these outputs when they transfer the tokens further.</p>

<p>The basic idea is that once a bin has been referenced as many times as its
size, it can safely be pruned from the ledger. This preserves both privacy and
security, but reduces the data that needs to be stored on the distributed
ledger. Randomization ensures that attackers cannot predict in which bin an
output will be placed. This prevents targeted flooding, allowing the system to
scale by increasing the number of bins while remaining resilient under
adversarial conditions. The research paper establishes this result by formally
defining a cryptocurrency and its unpredictability, untraceability, and
scalability notions. The work also presents a construction using Merkle trees
that illustrates how partitioning and pruning are possible over a well-known
authenticated data structure.</p>

<p>A detailed simulation of the new technique, using a transaction data set
gathered from the <a href="//www.getmonero.org">Monero cryptocurrency</a>, shows that the
storage space can be reduced by approximately 60% while maintaining the same
degree of privacy.</p>

<p>For more information, see <a href="//cryptobern.github.io/toxic_decoys/">this blog post</a> that explains the approach in more depth.</p>

<p>This work appears in the <a href="//petsymposium.org/popets/2025/">Proceedings on Privacy Enhancing Technologies
2025</a>.  Congratulations to <a href="/fxw/">François-Xavier
Wicht</a> for this success.</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[The research paper Toxic Decoys: A Path to Scaling Privacy-Preserving Cryptocurrencies has been accepted for publication in the Proceedings on Privacy Enhancing Technologies (PoPETs) and will be presented at corresponding symposium, PETS 2025, which takes place in Washington, DC, from July 14-19, 2025.]]></summary></entry><entry><title type="html">DAG-based asymmetric consensus</title><link href="/2025/06/11/asymmetric_dag.html" rel="alternate" type="text/html" title="DAG-based asymmetric consensus" /><published>2025-06-11T00:00:00+00:00</published><updated>2025-06-11T00:00:00+00:00</updated><id>/2025/06/11/asymmetric_dag</id><content type="html" xml:base="/2025/06/11/asymmetric_dag.html"><![CDATA[<p>The research paper <a href="//arxiv.org/abs/2505.17891">DAG-based Consensus with Asymmetric
Trust</a> has been accepted for presentation and
publication at the <a href="//www.podc.org/podc2025/">PODC 2025 conference</a>, the 44th
ACM Symposium on Principles of Distributed Computing, which is held in Santa
María Huatulco, Mexico, in June 2025.  This work addresses the
asymmetric-trust model, in which each participant is free to make its own
subjective and individual trust assumptions about others.  The paper shows the
first asymmetric protocol for computing a common core, equivalent to that in
the threshold model.  Implementing this primitive then leads to the first
randomized asynchronous DAG-based consensus protocol with asymmetric quorums,</p>

<p><a href="/jv/">Juan Villacis</a> will present this work there – congratulations!</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[The research paper DAG-based Consensus with Asymmetric Trust has been accepted for presentation and publication at the PODC 2025 conference, the 44th ACM Symposium on Principles of Distributed Computing, which is held in Santa María Huatulco, Mexico, in June 2025. This work addresses the asymmetric-trust model, in which each participant is free to make its own subjective and individual trust assumptions about others. The paper shows the first asymmetric protocol for computing a common core, equivalent to that in the threshold model. Implementing this primitive then leads to the first randomized asynchronous DAG-based consensus protocol with asymmetric quorums,]]></summary></entry><entry><title type="html">Best student paper award for David Lehnherr</title><link href="/2025/05/22/best_paper_award.html" rel="alternate" type="text/html" title="Best student paper award for David Lehnherr" /><published>2025-05-22T00:00:00+00:00</published><updated>2025-05-22T00:00:00+00:00</updated><id>/2025/05/22/best_paper_award</id><content type="html" xml:base="/2025/05/22/best_paper_award.html"><![CDATA[<p>The research paper <a href="//doi.org/10.1007/978-3-031-91736-3_11">Simplicial Belief</a>
has been accepted to the <a href="//www.torontomu.ca/sirocco-2025/">SIROCCO 2025
conference</a>, the 32nd International
Colloquium On Structural Information and Communication Complexity.  SIROCCO is
devoted to the study of the interplay between structural knowledge,
communication, and computing in decentralized systems of multiple
communicating entities.</p>

<p>More importantly, the paper has also won the <strong>best student paper award</strong> at
SIROCCO 2025.</p>

<p>Congratulations to <a href="/dl">David Lehnherr</a>!</p>]]></content><author><name>Cryptology and Data Security Research Group</name></author><summary type="html"><![CDATA[The research paper Simplicial Belief has been accepted to the SIROCCO 2025 conference, the 32nd International Colloquium On Structural Information and Communication Complexity. SIROCCO is devoted to the study of the interplay between structural knowledge, communication, and computing in decentralized systems of multiple communicating entities.]]></summary></entry></feed>