1. reproduce.debian.net
2. Fifty Years of Open Source Software Supply Chain Security
3. 4th CHAINS Software Supply Chain Workshop
4. Mailing list updates
5. Canonicalization for Unreproducible Builds in Java
6. OSS Rebuild adds new TUI features
7. Distribution roundup
8. diffoscope & strip-nondeterminism
9. Website updates
10. Reproducibility testing framework
11. Upstream patches

reproduce.debian.net The last few months have seen the introduction, development and deployment of reproduce.debian.net. In technical terms, this is an instance of rebuilderd, our server designed monitor the official package repositories of Linux distributions and attempt to reproduce the observed results there. This month, however, we are pleased to announce that reproduce.debian.net now tests all the Debian trixie architectures except s390x and mips64el. The ppc64el architecture was added through the generous support of Oregon State University Open Source Laboratory (OSUOSL), and we can support the armel architecture thanks to CodeThink.

Fifty Years of Open Source Software Supply Chain Security Russ Cox has published a must-read article in ACM Queue on Fifty Years of Open Source Software Supply Chain Security. Subtitled, For decades, software reuse was only a lofty goal. Now it s very real. , Russ article goes on to outline the history and original goals of software supply-chain security in the US military in the early 1970s, all the way to the XZ Utils backdoor of 2024. Through that lens, Russ explores the problem and how it has changed, and hasn t changed, over time. He concludes as follows:

We are all struggling with a massive shift that has happened in the past 10 or 20 years in the software industry. For decades, software reuse was only a lofty goal. Now it s very real. Modern programming environments such as Go, Node and Rust have made it trivial to reuse work by others, but our instincts about responsible behaviors have not yet adapted to this new reality. We all have more work to do.

4th CHAINS Software Supply Chain Workshop Convened as part of the CHAINS research project at the KTH Royal Institute of Technology in Stockholm, Sweden, the 4th CHAINS Software Supply Chain Workshop occurred during April. During the workshop, there were a number of relevant workshops, including:

• Signature, Attestations and Reproducible Builds
• Does Functional Package Management Enable Reproducible Builds at Scale?
• Causes and Mitigations of Unreproducible Builds in Java [paper]
• Fixing Breaking Dependency Updates Using LLMs
• The caveats of vulnerability analysis
• maven-lockfile (Lockfiles for Java and Maven)
• observer (Generating SBOMs for C/C++)
• dirty-waters (Transparency checks for software supply chains)
• A supply chain competition. Martin Schwaighofer, the winner, created a recap video (20m43s).
• Finally, 8 posters on dependency introspection, diverse double compilation, dependency management, VEX and SBOM.

The full listing of the agenda is available on the workshop s website.

Mailing list updates On our mailing list this month:

• Luca DiMaio of Chainguard posted to the list reporting that they had successfully implemented reproducible filesystem images with both ext4 and an EFI system partition. They go on to list the various methods, and the thread generated at least fifteen replies.
• David Wheeler announced that the OpenSSF is building a glossary of sorts in order that they consistently use the same meaning for the same term and, moreover, that they have drafted a definition for reproducible build . The thread generated a significant number of replies on the definition, leading to a potential update to the Reproducible Build s own definition.
• Lastly, kpcyrd posted to the list with a timely reminder and update on their repro-env tool. As first reported in our July 2023 report, kpcyrd mentions that:

  My initial interest in reproducible builds was how do I distribute pre-compiled binaries on GitHub without people raising security concerns about them . I ve cycled back to this original problem about 5 years later and built a tool that is meant to address this. [ ]

Canonicalization for Unreproducible Builds in Java Aman Sharma, Benoit Baudry and Martin Monperrus have published a new scholarly study related to reproducible builds within Java. Titled Canonicalization for Unreproducible Builds in Java, the article s abstract is as follows:

[ ] Achieving reproducibility at scale remains difficult, especially in Java, due to a range of non-deterministic factors and caveats in the build process. In this work, we focus on reproducibility in Java-based software, archetypal of enterprise applications. We introduce a conceptual framework for reproducible builds, we analyze a large dataset from Reproducible Central and we develop a novel taxonomy of six root causes of unreproducibility. We study actionable mitigations: artifact and bytecode canonicalization using OSS-Rebuild and jNorm respectively. Finally, we present Chains-Rebuild, a tool that raises reproducibility success from 9.48% to 26.89% on 12,283 unreproducible artifacts. To sum up, our contributions are the first large-scale taxonomy of build unreproducibility causes in Java, a publicly available dataset of unreproducible builds, and Chains-Rebuild, a canonicalization tool for mitigating unreproducible builds in Java.

A full PDF of their article is available from arXiv.

OSS Rebuild adds new TUI features OSS Rebuild aims to automate rebuilding upstream language packages (e.g. from PyPI, crates.io and npm registries) and publish signed attestations and build definitions for public use. OSS Rebuild ships a text-based user interface (TUI) for viewing, launching, and debugging rebuilds. While previously requiring ownership of a full instance of OSS Rebuild s hosted infrastructure, the TUI now supports a fully local mode of build execution and artifact storage. Thanks to Giacomo Benedetti for his usage feedback and work to extend the local-only development toolkit. Another feature added to the TUI was an experimental chatbot integration that provides interactive feedback on rebuild failure root causes and suggests fixes.

Distribution roundup In Debian this month:

• Roland Clobus posted another status report on reproducible ISO images on our mailing list this month, with the summary that all live images build reproducibly from the online Debian archive .
• Debian developer Simon Josefsson published another two reproducibility-related blog posts this month, the first on the topic of Verified Reproducible Tarballs. Simon sardonically challenges the reader as follows: Do you want a supply-chain challenge for the Easter weekend? Pick some well-known software and try to re-create the official release tarballs from the corresponding Git checkout. Is anyone able to reproduce anything these days? After that, they also published a blog post on Building Debian in a GitLab Pipeline using their multi-stage rebuild approach.
• Roland also posted to our mailing list to highlight that there is now another tool in Debian that generates reproducible output, equivs . This is a tool to create trivial Debian packages that might Depend on other packages. As Roland writes, building the [equivs] package has been reproducible for a while, [but] now the output of the [tool] has become reproducible as well .
• Lastly, 9 reviews of Debian packages were added, 10 were updated and 10 were removed this month adding to our extensive knowledge about identified issues.

The IzzyOnDroid Android APK repository made more progress in April. Thanks to funding by NLnet and Mobifree, the project was also to put more time into their tooling. For instance, developers can now easily run their own verification builder in less than 5 minutes . This currently supports Debian-based systems, but support for RPM-based systems is incoming.

• The rbuilder_setup tool can now setup the entire framework within less than five minutes. The process is configurable, too, so everything from just the basics to verify builds up to a fully-fledged RB environment is also possible.
• This tool works on Debian, RedHat and Arch Linux, as well as their derivates. The project has received successful reports from Debian, Ubuntu, Fedora and some Arch Linux derivates so far.
• Documentation on how to work with reproducible builds (making apps reproducible, debugging unreproducible packages, etc) is available in the project s wiki page.
• Future work is also in the pipeline, including documentation, guidelines and helpers for debugging.

NixOS defined an Outreachy project for improving build reproducibility. In the application phase, NixOS saw some strong candidates providing contributions, both on the NixOS side and upstream: guider-le-ecit analyzed a libpinyin issue. Tessy James fixed an issue in arandr and helped analyze one in libvlc that led to a proposed upstream fix. Finally, 3pleX fixed an issue which was accepted in upstream kitty, one in upstream maturin, one in upstream python-sip and one in the Nix packaging of python-libbytesize. Sadly, the funding for this internship fell through, so NixOS were forced to abandon their search. Lastly, in openSUSE news, Bernhard M. Wiedemann posted another monthly update for their work there.

diffoscope & strip-nondeterminism diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made the following changes, including preparing and uploading a number of versions to Debian:

• Use the --walk argument over the potentially dangerous alternative --scan when calling out to zipdetails(1). [ ]
• Correct a longstanding issue where many >-based version tests used in conditional fixtures were broken. This was used to ensure that specific tests were only run when the version on the system was newer than a particular number. Thanks to Colin Watson for the report (Debian bug #1102658) [ ]
• Address a long-hidden issue in the test_versions testsuite as well, where we weren t actually testing the greater-than comparisons mentioned above, as it was masked by the tests for equality. [ ]
• Update copyright years. [ ]

In strip-nondeterminism, however, Holger Levsen updated the Continuous Integration (CI) configuration in order to use the standard Debian pipelines via debian/salsa-ci.yml instead of using .gitlab-ci.yml. [ ]

Website updates Once again, there were a number of improvements made to our website this month including:

• Aman Sharma added OSS-Rebuild s stabilize tool to the Tools page. [ ][ ]
• Chris Lamb added a configure.ac (GNU Autotools) example for using SOURCE_DATE_EPOCH. [ ]. Chris also updated the SOURCE_DATE_EPOCH snippet and move the archive metadata to a more suitable location. [ ]
• Denis Carikli added GNU Boot to our ever-evolving Projects page.

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework running primarily at tests.reproducible-builds.org in order to check packages and other artifacts for reproducibility. In April, a number of changes were made by Holger Levsen, including:

• reproduce.debian.net-related:
  • Add armel.reproduce.debian.net to support the armel architecture. [ ][ ]
  • Add a new ARM node, codethink05. [ ][ ]
  • Add ppc64el.reproduce.debian.net to support testing of the ppc64el architecture. [ ][ ][ ]
  • Improve the reproduce.debian.net front page. [ ][ ]
  • Make various changes to the ppc64el nodes. [ ][ ]9[ ][ ]
  • Make various changes to the arm64 and armhf nodes. [ ][ ][ ][ ]
  • Various changes related to the rebuilderd-worker entry point. [ ][ ][ ]
  • Create and deploy a pkgsync script. [ ][ ][ ][ ][ ][ ][ ][ ]
  • Fix the monitoring of the riscv64 architecture. [ ][ ]
  • Make a number of changes related to starting the rebuilderd service. [ ][ ][ ][ ]
• Backup-related:
  • Backup the rebuilder databases every week. [ ][ ][ ][ ]
  • Improve the node health checks. [ ][ ]
• Misc:
  • Re-use existing connections to the SSH proxy node on the riscv64 nodes. [ ][ ]
  • Node maintenance. [ ][ ][ ]

In addition:

• Jochen Sprickerhof fixed the risvc64 host names [ ] and requested access to all the rebuilderd nodes [ ].
• Mattia Rizzolo updated the self-serve rebuild scheduling tool, replacing the deprecated SSO -style authentication with OpenIDC which authenticates against salsa.debian.org. [ ][ ][ ]
• Roland Clobus updated the configuration for the osuosl3 node to designate 4 workers for bigger builds. [ ]

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

• Bernhard M. Wiedemann
  • lout
  • mpiP
  • libabigail
  • cython
  • mpiP
  • godot
  • gnome-text-editor
  • clisp
  • rpm
  • Fiona
  • qtdoc
• Chris Hofstaedtler:
  • #1104512 filed against command-not-found.
  • #1104517 filed against command-not-found.
  • #1104535 filed against cc65.
• Chris Lamb:
  • #1102659 filed against vcsh.
  • #1103797 filed against schism.
  • #1103798 filed against magic-wormhole-mailbox-server.
  • #1103800 filed against openvpn3-client.
• James Addison:
  • #1102760 filed against apg.
• Jochen Sprickerhof:
  • #1103288 filed against courier.
  • #1103563 filed against cross-toolchain-base.

Finally, if you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

• IRC: #reproducible-builds on irc.oftc.net.
• Mastodon: @reproducible_builds@fosstodon.org
• Mailing list: rb-general@lists.reproducible-builds.org

Hi Joseph and all drivers of the "End of 10" campaign, On behalf of the entire Debian project, I would like to say that we proudly join your great campaign. We stand with you in promoting Free Software, defending users' freedoms, and protecting our planet by avoiding unnecessary hardware waste. Thank you for leading this important initiative.

Andreas Tille Debian Project Leader

1. DFSG Team
2. Archive Team (responsible for DAK maintenance and process tooling, including releases)

1. The MIA process, which handles inactive or unreachable maintainers.
2. Package Salvaging, which allows contributors to take over maintenance if conditions are met.
3. Non-Maintainer Uploads (NMUs), which are limited to specific, well-defined fixes (which do not include things like migration to Salsa).

• Encourage an idempotently rebuildable Debian archive, i.e., a Debian archive that can be 100% bit-by-bit identically rebuilt using Debian itself.
• Construct a smaller number of binary *.deb packages based on Guix binaries that when used as build inputs (potentially iteratively) leads to 100% bit-by-bit identical packages as in step 1.
• Encourage a freedom respecting distribution, similar to Trisquel, from this idempotently rebuildable Debian.

sed -i 's/ deb$/ deb deb-src/' /etc/apt/sources.list.d/*.sources
apt-get -o Acquire::Check-Valid-Until=false update
apt-get dist-upgrade -q -y
apt-get install -q -y --no-install-recommends build-essential fakeroot
env DEBIAN_FRONTEND=noninteractive \
    apt-get build-dep -y --only-source $PACKAGE=$VERSION
useradd -m build
DDB_BUILDDIR=/build/reproducible-path
chgrp build $DDB_BUILDDIR
chmod g+w $DDB_BUILDDIR
su build -c "apt-get source --only-source $PACKAGE=$VERSION" > ../$PACKAGE_$VERSION.build
cd $DDB_BUILDDIR
su build -c "dpkg-buildpackage"
cd ..
mkdir out
mv -v $(find $DDB_BUILDDIR -maxdepth 1 -type f) out/

if ! grep -q '^pool/**' .gitattributes; then
    git lfs track 'pool/**'
    git add .gitattributes
    git commit -m"Track pool/* with Git-LFS." .gitattributes
fi
POOLDIR=$(if test "$(echo "$PACKAGE"   cut -c1-3)" = "lib"; then C=4; else C=1; fi; echo "$DDB_PACKAGE"   cut -c1-$C)
mkdir -pv pool/main/$POOLDIR/
rm -rfv pool/main/$POOLDIR/$PACKAGE
mv -v out pool/main/$POOLDIR/$PACKAGE
git add pool
git commit -m"Add $PACKAGE." -m "$CI_JOB_URL" -m "$VERSION" -a
if test "$ DDB_GIT_TOKEN:- " = ""; then
    echo "SKIP: Skipping git push due to missing DDB_GIT_TOKEN (see README)."
else
    git push -o ci.skip
fi

• Optimize the stage-N build process by identifying the transitive closure of build dependencies from some initial set of packages.
• Create a build orchestrator that launches pipelines based on the previous list of packages, as necessary to fill the archive with necessary packages. Currently I m using a basic /bin/sh for loop around curl to trigger GitLab CI/CD pipelines with names derived from https://popcon.debian.org/.
• Create and publish a dists/ sub-directory, so that it is possible to use the newly built packages in the stage-1 build phase.
• Produce diffoscope-style differences of built packages, both stage0 against official binaries and between stage0 and stage1.
• Create the stage-1 build containers and stage-1 archive.
• Review build failures. On amd64 and arm64 the list is small (below 10 out of ~5000 builds), but on riscv64 there is some icache-related problem that affects Java JVM that triggers build failures.
• Provide GitLab pipeline based builds of the Debian docker container images, cloud-images, debian-live CD and debian-installer ISO s.
• Provide integration with Sigstore and Sigsum for signing of Debian binaries with transparency-safe properties.
• Implement a simple replacement for dpkg and apt using /bin/sh for use during bootstrapping when neither packaging tools are available.

Debian LTS contributors In March, 20 contributors have been paid to work on Debian LTS, their reports are available:

• Adrian Bunk did 51.5h (out of 0.0h assigned and 51.5h from previous period).
• Andreas Henriksson did 20.0h (out of 20.0h assigned).
• Andrej Shadura did 6.0h (out of 10.0h assigned), thus carrying over 4.0h to the next month.
• Bastien Roucari s did 20.0h (out of 20.0h assigned).
• Ben Hutchings did 12.0h (out of 12.0h assigned and 12.0h from previous period), thus carrying over 12.0h to the next month.
• Chris Lamb did 18.0h (out of 18.0h assigned).
• Daniel Leidert did 26.0h (out of 23.0h assigned and 3.0h from previous period).
• Emilio Pozuelo Monfort did 37.0h (out of 36.5h assigned and 0.75h from previous period), thus carrying over 0.25h to the next month.
• Guilhem Moulin did 8.25h (out of 11.0h assigned and 9.0h from previous period), thus carrying over 11.75h to the next month.
• Jochen Sprickerhof did 18.0h (out of 24.25h assigned and 3.0h from previous period), thus carrying over 9.25h to the next month.
• Lee Garrett did 10.25h (out of 0.0h assigned and 42.0h from previous period), thus carrying over 31.75h to the next month.
• Lucas Kanashiro did 4.0h (out of 0.0h assigned and 56.0h from previous period), thus carrying over 52.0h to the next month.
• Markus Koschany did 27.25h (out of 27.25h assigned).
• Roberto C. S nchez did 8.25h (out of 7.0h assigned and 17.0h from previous period), thus carrying over 15.75h to the next month.
• Santiago Ruano Rinc n did 17.5h (out of 19.75h assigned and 5.25h from previous period), thus carrying over 7.5h to the next month.
• Sean Whitton did 7.0h (out of 7.0h assigned).
• Sylvain Beucler did 32.0h (out of 31.0h assigned and 1.25h from previous period), thus carrying over 0.25h to the next month.
• Thorsten Alteholz did 11.0h (out of 11.0h assigned).
• Tobias Frost did 7.75h (out of 12.0h assigned), thus carrying over 4.25h to the next month.
• Utkarsh Gupta did 15.0h (out of 15.0h assigned).

Evolution of the situation In March, we have released 31 DLAs.

• Notable security updates:
  • linux-6.1 (1 2)and linux, prepared by Ben Hutchings, fixed an extensive list of vulnerabilities
  • firefox-esr, prepared by Emilio Pozuelo Monfort, fixed a variety of vulnerabilities
  • intel-microcode, prepared by Tobias Frost, fixed several local privilege escalation, denial of service, and information disclosure vulnerabilities
  • vim, prepared by Sean Whitton, fixed a multitude of vulnerabilities, including many application crashes, buffer overflows, and out-of-bounds reads

The recent trend of contributions from contributors external to the formal LTS team has continued. LTS contributor Sylvain Beucler reviewed and facilitated an update to openvpn proposed by Aquila Macedo, resulting in the publication of DLA 4079-1. Thanks a lot to Aquila for preparing the update. The LTS Team continues to make contributions to the current stable Debian release, Debian 12 (codename bookworm ). LTS contributor Bastien Roucari s prepared a stable upload of krb5 to ensure that fixes made in the LTS release, Debian 11 (codename bullseye ) were also made available to stable users. Additional stable updates, for tomcat10 and jetty9, were prepared by LTS contributor Markus Koschany. And, finally, LTS contributor Utkarsh Gupta prepared stable updates for rails and ruby-rack. LTS contributor Emilio Pozuelo Monfort has continued his ongoing improvements to the Debian security tracker and its associated tooling, making the data contained in the tracker more reliable and easing interaction with it. The ckeditor3 package, which has been EOL by upstream for some time, is still depended upon by the PHP Horde packages in Debian. Sylvain, along with Bastien, did monumental work in coordinating with maintainers, security team fellows, and other Debian teams, to formally declare the EOL of the ckeditor3 package in Debian 11 and in Debian 12. Additionally, as a result of this work Sylvain has worked towards the removal of ckeditor3 as a dependency by other packages in order to facilitate the complete removal of ckeditor3 from all future Debian releases.

Thanks to our sponsors Sponsors that joined recently are in bold.

• Platinum sponsors:
  • Toshiba Corporation (for 114 months)
  • Civil Infrastructure Platform (CIP) (for 82 months)
  • VyOS Inc (for 47 months)
• Gold sponsors:
  • Roche Diagnostics International AG (for 125 months)
  • Akamai - Linode (for 119 months)
  • Babiel GmbH (for 108 months)
  • Plat Home (for 108 months)
  • University of Oxford (for 65 months)
  • Deveryware (for 52 months)
  • EDF SA (for 36 months)
  • Dataport A R (for 12 months)
  • CERN (for 9 months)
• Silver sponsors:
  • Domeneshop AS (for 129 months)
  • Nantes M tropole (for 123 months)
  • Univention GmbH (for 115 months)
  • Universit Jean Monnet de St Etienne (for 115 months)
  • Ribbon Communications, Inc. (for 109 months)
  • Exonet B.V. (for 99 months)
  • Leibniz Rechenzentrum (for 93 months)
  • Minist re de l Europe et des Affaires trang res (for 77 months)
  • Cloudways by DigitalOcean (for 66 months)
  • Dinahosting SL (for 64 months)
  • Bauer Xcel Media Deutschland KG (for 59 months)
  • Platform.sh SAS (for 59 months)
  • Moxa Inc. (for 53 months)
  • sipgate GmbH (for 50 months)
  • OVH US LLC (for 48 months)
  • Tilburg University (for 48 months)
  • GSI Helmholtzzentrum f r Schwerionenforschung GmbH (for 40 months)
  • Soliton Systems K.K. (for 37 months)
  • THINline s.r.o. (for 13 months)
  • Copenhagen Airports A/S (for 6 months)
• Bronze sponsors:
  • Evolix (for 130 months)
  • Seznam.cz, a.s. (for 130 months)
  • Linuxhotel GmbH (for 127 months)
  • Intevation GmbH (for 126 months)
  • Daevel SARL (for 125 months)
  • Bitfolk LTD (for 124 months)
  • Megaspace Internet Services GmbH (for 124 months)
  • Greenbone AG (for 123 months)
  • NUMLOG (for 123 months)
  • WinGo AG (for 123 months)
  • Entr ouvert (for 114 months)
  • Adfinis AG (for 112 months)
  • Laboratoire LEGI - UMR 5519 / CNRS (for 106 months)
  • Tesorion (for 106 months)
  • Bearstech (for 98 months)
  • LiHAS (for 98 months)
  • Catalyst IT Ltd (for 92 months)
  • Supagro (for 88 months)
  • Demarcq SAS (for 86 months)
  • Universit Grenoble Alpes (for 72 months)
  • TouchWeb SAS (for 65 months)
  • SPiN AG (for 61 months)
  • CoreFiling (for 57 months)
  • Institut des sciences cognitives Marc Jeannerod (for 52 months)
  • Observatoire des Sciences de l Univers de Grenoble (for 49 months)
  • Tem Innovations GmbH (for 44 months)
  • WordFinder.pro (for 43 months)
  • CNRS DT INSU R sif (for 42 months)
  • Alter Way (for 35 months)
  • Institut Camille Jordan (for 25 months)
  • SOBIS Software GmbH (for 9 months)
  • Tuxera Inc.

• bluez
• nss
• libmojolicious-perl
• uw-imap
• dnsmasq
• firmware-nonfree
• activemq
• frr
• libmodbus

• CI/CD pipelines: We used CI/CD pipelines on salsa.debian.org all the times to automate tasks such as building, linting, and testing packages. For any package I worked on that lacked CI/CD integration, setting it up became my first step.
• autopkgtest: There s a strong emphasis on autopkgtest as the mechanism for running functional tests and ensuring that security patches don t introduce regressions. I contributed by both extending existing test suites and writing new ones from scratch.
• Toolchain complexity for older releases: Working with older Debian versions like Jessie brought some unique challenges. Getting a development environment up and running often meant troubleshooting issues with sbuild chroots, qemu images, and other tools that don t just work like they tend to on Debian stable.
• Community collaboration: The people involved in LTS and ELTS are extremely helpful and collaborative. Requests for help, code reviews, and general feedback were usually answered quickly.
• Shared ownership: This collaborative culture also meant that contributors would regularly pick up work left by others or hand off their own tasks when needed. That mutual support made a big difference.
• Backporting security fixes: This is probably the most intense and most rewarding activity. It involves manually adapting patches to work on older codebases when upstream patches don t apply cleanly. This requires deep code understanding and thorough testing.
• Upstream collaboration: Reaching out to upstream developers was a key part of my workflow. I often asked if they could provide patches for older versions or at least review my backports. Sometimes they were available, but most of the time, the responsibility remained on us.
• Diverse tech stack: The work exposed me to a wide range of programming languages and frameworks Python, Java, C, Perl, and more. Unsurprisingly, some modern languages (like Go) are less prevalent in older releases like Jessie.
• Security team interaction: I had frequent contact with the core Debian Security Team the folks responsible for security in Debian stable. This gave me a broader perspective on how Debian handles security holistically.

The Evolution of Open Source Open source won. Over the 25+ years I ve been involved in the open source movement, I ve witnessed its remarkable evolution. Today, Linux powers billions of devices from tiny embedded systems and Android smartphones to massive cloud datacenters and even space stations. Examine any modern large-scale digital system, and you ll discover it s built upon thousands of open source projects. I feel the priority for the open source movement should no longer be increasing adoption, but rather solving how to best maintain the vast ecosystem of software. This requires building robust institutions and processes to secure proper resourcing and ensure the collaborative development process remains efficient and leads to ever-increasing quality of software.

What is Special About Debian? Debian, established in 1993 by Ian Murdock, stands as one of these institutions that has demonstrated exceptional resilience. There is no single authority, but instead a complex web of various stakeholders, each with their own goals and sources of funding. Every idea needs to be championed at length to a wide audience and implemented through a process of organic evolution. Thanks to this approach, Debian has been consistently delivering production-quality, universally useful software for over three decades. Having been a Debian Developer for more than ten years, I m well-positioned to contribute meaningfully to this community. If your organization relies on Debian or its derivatives such as Ubuntu, and you re interested in funding cyber infrastructure maintenance by sponsoring Debian work, please don t hesitate to reach out. This could include package maintenance and version currency, improving automated upgrade testing, general quality assurance and supply chain security enhancements.

Best way to reach me is by e-mail otto at debian.org. You can also book a 15-minute chat with me for a quick introduction.

Grow or Die My four-year tenure as a Software Development Manager at Amazon Web Services was very interesting. I m grateful for my time at AWS and proud of my team s accomplishments, particularly for creating an open source contribution process that got Amazon from zero to the largest external contributor to the MariaDB open source database. During this time, I got to experience and witness a plethora of interesting things. I will surely share some of my key learnings in future blog posts. Unfortunately, the rate of progress in this mammoth 1.5 million employee organization was slowing down, and I didn t feel I learned much new in the last years. This realization, combined with the opportunity cost of not spending enough time on new cutting-edge technology, motivated me to take this leap. Being a full-time open source developer may not be financially the most lucrative idea, but I think it is an excellent way to force myself to truly assess what is important on a global scale and what areas I want to contribute to. Working fully on open source presents a fascinating duality: you re not bound by any external resource or schedule limitations, and can the progress you make is directly proportional to how much energy you decide to invest. Yet, you also depend on collaboration with people you might never meet and who are not financially incentivized to collaborate. This will undoubtedly expose me to all kinds of challenges. But what would be better in fostering holistic personal growth? I know that deep down in my DNA, I am not made to stay cozy or to do easy things. I need momentum. OK, let s get going

• Computing pointers past &array[size+1]. I found no cases where the resulting pointers were actually used, but the mere computation is still undefined behavior. These were fixed by adjusting the code to avoid computing pointers like this. The result was clearer code, which is good.
• Signed arithmetic overflow in PRNG code. There are several linear congruential PRNGs in the library which used signed integer arithmetic. The rand48 generator carefully used unsigned short values. Of course, in C, the arithmetic performed on them is done with signed ints if int is wider than short. C specifies signed overflow as undefined, but both gcc and clang generate the expected code anyways. The fixes here were simple; just switch the computations to unsigned arithmetic, adjusting types and inserting casts as required.
• Passing pointers to the middle of a data structure. For example, free takes a pointer to the start of an allocation. The management structure appears just before that in memory; computing the address of which appears to be undefined behavior to the compiler. The only fix I could do here was to disable the sanitizer in functions doing these computations -- the sanitizer was mis-detecting correct code and it doesn't provide a way to skip checks on a per-operator basis.
• Null pointer plus or minus zero. C says that any arithmetic with the NULL pointer is undefined, even when the value being added or subtracted is zero. The fix here was to create a macro, enabled only when the sanitizer is enabled, which checks for this case and skips the arithmetic.
• Discarded computations which overflow. A couple of places computed a value, then checked if that would have overflowed and discard the result. Even though the program doesn't depend upon the computation, its mere presence is undefined behavior. These were fixed by moving the computation into an else clause in the overflow check. This inserts an extra branch instruction, which is annoying.
• Signed integer overflow in math code. There's a common pattern in various functions that want to compare against 1.0. Instead of using the floating point equality operator, they do the computation using the two 32-bit halves with ((hi - 0x3ff00000) lo) == 0. It's efficient, but because most of these functions store the 'hi' piece in a signed integer (to make checking the sign bit fast), the result is undefined when hi is a large negative value. These were fixed by inserting casts to unsigned types as the results were always tested for equality.

    #define lsl(__x,__s) ((sizeof(__x) == sizeof(char)) ?                   \
                          (__typeof(__x)) ((unsigned char) (__x) << (__s)) :  \
                          (sizeof(__x) == sizeof(short)) ?                  \
                          (__typeof(__x)) ((unsigned short) (__x) << (__s)) : \
                          (sizeof(__x) == sizeof(int)) ?                    \
                          (__typeof(__x)) ((unsigned int) (__x) << (__s)) :   \
                          (sizeof(__x) == sizeof(long)) ?                   \
                          (__typeof(__x)) ((unsigned long) (__x) << (__s)) :  \
                          (sizeof(__x) == sizeof(long long)) ?              \
                          (__typeof(__x)) ((unsigned long long) (__x) << (__s)) : \
                          __undefined_shift_size(__x, __s))

    int
    __asr_int(int x, int s)  
        return x < 0 ? ~(~x >> s) : x >> s;
     

    #define asr(__x,__s) ((sizeof(__x) == sizeof(char)) ?           \
                          (__typeof(__x))__asr_char(__x, __s) :       \
                          (sizeof(__x) == sizeof(short)) ?          \
                          (__typeof(__x))__asr_short(__x, __s) :      \
                          (sizeof(__x) == sizeof(int)) ?            \
                          (__typeof(__x))__asr_int(__x, __s) :        \
                          (sizeof(__x) == sizeof(long)) ?           \
                          (__typeof(__x))__asr_long(__x, __s) :       \
                          (sizeof(__x) == sizeof(long long)) ?      \
                          (__typeof(__x))__asr_long_long(__x, __s):   \
                          __undefined_shift_size(__x, __s))

for (ix = -1022, i = hx << 11; i > 0; i <<= 1)
    ix -= 1;

hx += n << 20;
if (hx >> 20 <= 0)
    /* do sub-normal things */

1. setlocale/newlocale didn't check for NULL locale names
2. qsort was using uintptr_t to swap data around. On MSP430 in 'large' mode, that's a 20-bit type inside a 32-bit representation.
3. random() was returning values in int range rather than long.
4. m68k assembly for memcpy was broken for sizes > 64kB.
5. freopen returned NULL, even on success
6. The optimized version of memrchr was always performing unaligned accesses.
7. String to float conversion had a table missing four values. This caused an array access overflow which resulted in imprecise values in some cases.
8. vfwscanf mis-parsed floating point values by assuming that wchar_t was unsigned.

    p = malloc(sizeof(*p) * c);

What makes communications secure? When most people are talking about secure communications, they mean some combination of these properties:

1. Privacy - nobody except the intended recipient can decode a message.
2. Authentication - guarantees that the person you are chatting with really is the intended recipient.
3. Ephemerality - preventing a record of the communication from being stored. That is, making it more like a conversation around the table than a written email.
4. Anonymity - keeping your set of contacts to yourself and even obfuscating the fact that communications are occurring.

If you think about it, most people care the most about the first two. In fact, authentication is a key part of privacy. There is an attack known as man in the middle in which somebody pretends to be the intended recipient. The interceptor reads the messages, and then passes them on to the real intended recipient. So we can t really have privacy without authentication. I ll have more to say about these later. For now, let s discuss attack scenarios.

What compromises security? There are a number of ways that security can be compromised. Let s think through some of them:

Communications infrastructure snooping Let s say you used no encryption at all, and connected to public WiFi in a coffee shop to send your message. Who all could potentially see it?

• The owner of the coffee shop s WiFi
• The coffee shop s Internet provider
• The recipient s Internet provider
• Any Internet providers along the network between the sender and the recipient
• Any government or institution that can compel any of the above to hand over copies of the traffic
• Any hackers that compromise any of the above systems

Back in the early days of the Internet, most traffic had no encryption. People were careful about putting their credit cards into webpages and emails because they knew it was easy to intercept them. We have been on a decades-long evolution towards more pervasive encryption, which is a good thing. Text messages (SMS) follow a similar path to the above scenario, and are unencrypted. We know that all of the above are ways people s texts can be compromised; for instance, governments can issue search warrants to obtain copies of texts, and China is believed to have a persistent hack into western telcos. SMS fails all four of our attributes of secure communication above (privacy, authentication, ephemerality, and anonymity). Also, think about what information is collected from SMS and by who. Texts you send could be retained in your phone, the recipient s phone, your phone company, their phone company, and so forth. They might also live in cloud backups of your devices. You only have control over your own phone s retention. So defenses against this involve things like:

• Strong end-to-end encryption, so no intermediate party even the people that make the app can snoop on it.
• Using strong authentication of your peers
• Taking steps to prevent even app developers from being able to see your contact list or communication history

You may see some other apps saying they use strong encryption or use the Signal protocol. But while they may do that for some or all of your message content, they may still upload your contact list, history, location, etc. to a central location where it is still vulnerable to these kinds of attacks. When you think about anonymity, think about it like this: if you send a letter to a friend every week, every postal carrier that transports it even if they never open it or attempt to peak inside will be able to read the envelope and know that you communicate on a certain schedule with that friend. The same can be said of SMS, email, or most encrypted chat operators. Signal s design prevents it from retaining even this information, though nation-states or ISPs might still be able to notice patterns (every time you send something via Signal, your contact receives something from Signal a few milliseconds later). It is very difficult to provide perfect anonymity from well-funded adversaries, even if you can provide very good privacy.

Device compromise Let s say you use an app with strong end-to-end encryption. This takes away some of the easiest ways someone could get to your messages. But it doesn t take away all of them. What if somebody stole your phone? Perhaps the phone has a password, but if an attacker pulled out the storage unit, could they access your messages without a password? Or maybe they somehow trick or compel you into revealing your password. Now what? An even simpler attack doesn t require them to steal your device at all. All they need is a few minutes with it to steal your SIM card. Now they can receive any texts sent to your number - whether from your bank or your friend. Yikes, right? Signal stores your data in an encrypted form on your device. It can protect it in various ways. One of the most important protections is ephemerality - it can automatically delete your old texts. A text that is securely erased can never fall into the wrong hands if the device is compromised later. An actively-compromised phone, though, could still give up secrets. For instance, what if a malicious keyboard app sent every keypress to an adversary? Signal is only as secure as the phone it runs on but still, it protects against a wide variety of attacks.

Untrustworthy communication partner Perhaps you are sending sensitive information to a contact, but that person doesn t want to keep it in confidence. There is very little you can do about that technologically; with pretty much any tool out there, nothing stops them from taking a picture of your messages and handing the picture off.

Environmental compromise Perhaps your device is secure, but a hidden camera still captures what s on your screen. You can take some steps against things like this, of course.

Human error Sometimes humans make mistakes. For instance, the reason a reporter got copies of messages recently was because a participant in a group chat accidentally added him (presumably that participant meant to add someone else and just selected the wrong name). Phishing attacks can trick people into revealing passwords or other sensitive data. Humans are, quite often, the weakest link in the chain.

Protecting yourself So how can you protect yourself against these attacks? Let s consider:

• Use a secure app like Signal that uses strong end-to-end encryption where even the provider can t access your messages
• Keep your software and phone up-to-date
• Be careful about phishing attacks and who you add to chat rooms
• Be aware of your surroundings; don t send sensitive messages where people might be looking over your shoulder with their eyes or cameras

There are other methods besides Signal. For instance, you could install GnuPG (GPG) on a laptop that has no WiFi card or any other way to connect it to the Internet. You could always type your messages on that laptop, encrypt them, copy the encrypted text to a floppy disk (or USB device), take that USB drive to your Internet computer, and send the encrypted message by email or something. It would be exceptionally difficult to break the privacy of messages in that case (though anonymity would be mostly lost). Even if someone got the password to your secure laptop, it wouldn t do them any good unless they physically broke into your house or something. In some ways, it is probably safer than Signal. (For more on this, see my article How gapped is your air?) But, that approach is hard to use. Many people aren t familiar with GnuPG. You don t have the convenience of sending a quick text message from anywhere. Security that is hard to use most often simply isn t used. That is, you and your friends will probably just revert back to using insecure SMS instead of this GnuPG approach because SMS is so much easier. Signal strikes a unique balance of providing very good security while also being practical, easy, and useful. For most people, it is the most secure option available. Signal is also open source; you don t have to trust that it is as secure as it says, because you can inspect it for yourself. Also, while it s not federated, I previously addressed that.

Government use If you are a government, particularly one that is highly consequential to the world, you can imagine that you are a huge target. Other nations are likely spending billions of dollars to compromise your communications. Signal itself might be secure, but if some other government can add spyware to your phones, or conduct a successful phishing attack, you can still have your communications compromised. I have no direct knowledge, but I think it is generally understood that the US government maintains communications networks that are entirely separate from the Internet and can only be accessed from secure physical locations and secure rooms. These can be even more secure than the average person using Signal because they can protect against things like environmental compromise, human error, and so forth. The scandal in March of 2025 happened because government employees were using Signal rather than official government tools for sensitive information, had taken advantage of Signal s ephemerality (laws require records to be kept), and through apparent human error had directly shared this information with a reporter. Presumably a reporter would have lacked access to the restricted communications networks in the first place, so that wouldn t have been possible. This doesn t mean that Signal is bad. It just means that somebody that can spend billions of dollars on security can be more secure than you. Signal is still a great tool for people, and in many cases defeats even those that can spend lots of dollars trying to defeat it. And remember - to use those restricted networks, you have to go to specific rooms in specific buildings. They are still not as convenient as what you carry around in your pocket.

Conclusion Signal is practical security. Do you want phone companies reading your messages? How about Facebook or X? Have those companies demonstrated that they are completely trustworthy throughout their entire history? I say no. So, go install Signal. It s the best, most practical tool we have.

---

This post is also available on my website, where it may be periodically updated.

Debian LTS contributors In February, 18 contributors have been paid to work on Debian LTS, their reports are available:

• Abhijith PA did 10.0h (out of 8.0h assigned and 6.0h from previous period), thus carrying over 4.0h to the next month.
• Adrian Bunk did 12.0h (out of 0.0h assigned and 63.5h from previous period), thus carrying over 51.5h to the next month.
• Andrej Shadura did 10.0h (out of 6.0h assigned and 4.0h from previous period).
• Bastien Roucari s did 20.0h (out of 20.0h assigned).
• Ben Hutchings did 12.0h (out of 8.0h assigned and 16.0h from previous period), thus carrying over 12.0h to the next month.
• Chris Lamb did 18.0h (out of 18.0h assigned).
• Daniel Leidert did 23.0h (out of 20.0h assigned and 6.0h from previous period), thus carrying over 3.0h to the next month.
• Emilio Pozuelo Monfort did 53.0h (out of 53.0h assigned and 0.75h from previous period), thus carrying over 0.75h to the next month.
• Guilhem Moulin did 11.0h (out of 3.25h assigned and 16.75h from previous period), thus carrying over 9.0h to the next month.
• Jochen Sprickerhof did 27.0h (out of 30.0h assigned), thus carrying over 3.0h to the next month.
• Lee Garrett did 11.75h (out of 9.5h assigned and 44.25h from previous period), thus carrying over 42.0h to the next month.
• Markus Koschany did 40.0h (out of 40.0h assigned).
• Roberto C. S nchez did 7.0h (out of 14.75h assigned and 9.25h from previous period), thus carrying over 17.0h to the next month.
• Santiago Ruano Rinc n did 19.75h (out of 21.75h assigned and 3.25h from previous period), thus carrying over 5.25h to the next month.
• Sean Whitton did 6.0h (out of 6.0h assigned).
• Sylvain Beucler did 52.5h (out of 14.75h assigned and 39.0h from previous period), thus carrying over 1.25h to the next month.
• Thorsten Alteholz did 11.0h (out of 11.0h assigned).
• Tobias Frost did 17.0h (out of 17.0h assigned).

Evolution of the situation In February, we have released 38 DLAs.

• Notable security updates:
  • pam-u2f, prepared by Patrick Winnertz, fixed an authentication bypass vulnerability
  • openjdk-17, prepared by Emilio Pozuelo Monfort, fixed an authorization bypass/information disclosure vulnerability
  • firefox-esr, prepared by Emilio Pozuelo Monfort, fixed several vulnerabilities
  • thunderbird, prepared by Emilio Pozuelo Monfort, fixed several vulnerabilities
  • postgresql-13, prepared by Christoph Berg, fixed an SQL injection vulnerability
  • freerdp2, prepared by Tobias Frost, fixed several vulnerabilities
  • openssh, prepared by Colin Watson, fixed a machine-in-the-middle vulnerability

LTS contributors Emilio Pozuelo Monfort and Santiago Ruano Rinc n coordinated the administrative aspects of LTS updates of postgresql-13 and pam-u2f, which were prepared by the respective maintainers, to whom we are most grateful. As has become the custom of the LTS team, work is under way on a number of package updates targeting Debian 12 (codename bookworm ) with fixes for a variety of vulnerabilities. In February, Guilhem Moulin prepared an upload of sssd, while several other updates are still in progress. Bastien Roucari s prepared an upload of krb5 for unstable as well. Given the importance of the Debian Security Tracker to the work of the LTS Team, we regularly contribute improvements to it. LTS contributor Emilio Pozuelo Monfort reviewed and merged a change to improve performance, and then dealt with unexpected issues that arose as a result. He also made improvements in the processing of CVEs which are not applicable to Debian. Looking to the future (the release of Debian 13, codename trixie , and beyond), LTS contributor Santiago Ruano Rinc n has initiated a conversation among the broader community involved in the development of Debian. The purpose of the discussion is to explore ways to improve the long term supportability of packages in Debian, specifically by focusing effort on ensuring that each Debian release contains the best supported upstream version of packages with a history of security issues.

Thanks to our sponsors Sponsors that joined recently are in bold.

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• Bronze sponsors:
  • Evolix (for 129 months)
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  • Catalyst IT Ltd (for 91 months)
  • Supagro (for 87 months)
  • Demarcq SAS (for 85 months)
  • Universit Grenoble Alpes (for 71 months)
  • TouchWeb SAS (for 64 months)
  • SPiN AG (for 60 months)
  • CoreFiling (for 56 months)
  • Institut des sciences cognitives Marc Jeannerod (for 51 months)
  • Observatoire des Sciences de l Univers de Grenoble (for 48 months)
  • Tem Innovations GmbH (for 43 months)
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  • Alter Way (for 34 months)
  • Institut Camille Jordan (for 24 months)
  • SOBIS Software GmbH (for 8 months)
  • Tuxera Inc.

• Release artifacts should be built in a way that can be reproduced by others
• It should be possible to build a project from source tarball that doesn t contain any generated or vendor files (e.g., in the style of git-archive).

Version Handling To build usable binaries from a minimal tarballs, it need to know which version number it is. Traditionally this information was stored inside configure.ac in git. However I use gnulib s git-version-gen to infer the version number from the git tag or git commit instead. The git tag information is not available in a git-archive tarball. My solution to this was to make use of the export-subst feature of the .gitattributes file. I store the file .tarball-version-git in git containing the magic cookie like this:

$Format:%(describe)$

With this, git-archive will replace with a useful version identifier on export, see the libtasn1 patch to achieve this. To make use of this information, the git-version-gen script was enhanced to read this information, see the gnulib patch. This is invoked by ./configure to figure out which version number the package is for.

Translations We want translations to be included in the minimal source tarball for it to be buildable. Traditionally these files are retrieved by the maintainer from the Translation project when running ./bootstrap, however there are two problems with this. The first one is that there is no strong authentication or versioning information on this data, the tools just download and place whatever wget downloaded into your source tree (printf-style injection attack anyone?). We could improve this (e.g., publish GnuPG signed translations messages with clear versioning), however I did not work on that further. The reason is that I want to support offline builds of packages. Downloading random things from the Internet during builds does not work when building a Debian package, for example. The translation project could solve this by making a monthly tarball with their translations available, for distributors to pick up and provide as a separate package that could be used as a build dependency. However that is not how these tools and projects are designed. Instead I reverted back to storing translations in git, something that I did for most projects back when I was using CVS 20 years ago. Hooking this into ./bootstrap and gettext workflow can be tricky (ideas for improvement most welcome!), but I used a simple approach to store all directly downloaded po/*.po files directly as po/*.po.in and make the ./bootstrap tool move them in place, see the libidn2 commit followed by the actual make update-po commit with all the translations where one essential step is:

# Prime po/*.po from fall-back copy stored in git.
for poin in po/*.po.in; do
    po=$(echo $poin   sed 's/.in//')
    test -f $po   cp -v $poin $po
done
ls po/*.po   sed 's .*/ ; s \.po$ ' > po/LINGUAS

Fetching vendor files like gnulib Most build dependencies are in the shape of You need a C compiler . However some come in the shape of source-code files intended to be vendored , and gnulib is a huge repository of such files. The latter is a problem when building from a minimal git archive. It is possible to consider translation files as a class of vendor files, since they need to be copied verbatim into the project build directory for things to work. The same goes for *.m4 macros from the GNU Autoconf Archive. However I m not confident that the solution for all vendor files must be the same. For translation files and for Autoconf Archive macros, I have decided to put these files into git and merge them manually occasionally. For gnulib files, in some projects like OATH Toolkit I also store all gnulib files in git which effectively resolve this concern. (Incidentally, the reason for doing so was originally that running ./bootstrap took forever since there is five gnulib instances used, which is no longer the case since gnulib-tool was rewritten in Python.) For most projects, however, I rely on ./bootstrap to fetch a gnulib git clone when building. I like this model, however it doesn t work offline. One way to resolve this is to make the gnulib git repository available for offline use, and I ve made some effort to make this happen via a Gnulib Git Bundle and have explained how to implement this approach for Debian packaging. I don t think that is sufficient as a generic solution though, it is mostly applicable to building old releases that uses old gnulib files. It won t work when building from CI/CD pipelines, for example, where I have settled to use a crude way of fetching and unpacking a particular gnulib snapshot, see this Libntlm patch. This is much faster than working with git submodules and cloning gnulib during ./bootstrap. Essentially this is doing:

GNULIB_REVISION=$(. bootstrap.conf >&2; echo $GNULIB_REVISION)
wget -nv https://gitlab.com/libidn/gnulib-mirror/-/archive/$GNULIB_REVISION/gnulib-mirror-$GNULIB_REVISION.tar.gz
gzip -cd gnulib-mirror-$GNULIB_REVISION.tar.gz   tar xf -
rm -fv gnulib-mirror-$GNULIB_REVISION.tar.gz
export GNULIB_SRCDIR=$PWD/gnulib-mirror-$GNULIB_REVISION
./bootstrap --no-git
./configure
make

Test the git-archive tarball This goes without saying, but if you don t test that building from a git-archive style tarball works, you are likely to regress at some point. Use CI/CD techniques to continuously test that a minimal git-archive tarball leads to a usable build.

Mission Accomplished So that wasn t hard, was it? You should now be able to publish a minimal git-archive tarball and users should be able to build your project from it. I recommend naming these archives as PROJECT-vX.Y.Z-src.tar.gz replacing PROJECT with your project name and X.Y.Z with your version number. The archive should have only one sub-directory named PROJECT-vX.Y.Z/ containing all the source-code files. This differentiate it against traditional PROJECT-X.Y.Z.tar.gz tarballs in that it embeds the git tag (which typically starts with v) and contains a wildcard-friendly -src substring. Alas there is no consistency around this naming pattern, and GitLab, GitHub, Codeberg etc all seem to use their own slightly incompatible variant. Let s go on to see what is needed to achieve reproducible make dist source tarballs. This is the release artifact that most users use, and they often contain lots of generated files and vendor files. These files are included to make it easy to build for the user. What are the challenges to make these reproducible?

Build dependencies causing different generated content The first part is to realize that if you use tool X with version A to generate a file that goes into the tarball, version B of that tool may produce different outputs. This is a generic concern and it cannot be solved. We want our build tools to evolve and produce better outputs over time. What can be addressed is to avoid needless differences. For example, many tools store timestamps and versioning information in the generated files. This causes needless differences, which makes audits harder. I have worked on some of these, like Autoconf Archive timestamps but solving all of these examples will take a long time, and some upstream are reluctant to incorporate these changes. My approach meanwhile is to build things using similar environments, and compare the outputs for differences. I ve found that the various closely related forks of GNU/Linux distributions are useful for this. Trisquel 11 is based on Ubuntu 22.04, and building my projects using both and comparing the differences only give me the relevant differences to improve. This can be extended to compare AlmaLinux with RockyLinux (for both versions 8 and 9), Devuan 5 against Debian 12, PureOS 10 with Debian 11, and so on.

Timestamps Sometimes tools store timestamps in files in a way that is harder to fix. Two notable examples of this are *.po translation files and Texinfo manuals. For translation files, I have resolved this by making sure the files use a predictable POT-Creation-Date timestamp, and I set it to the modification timestamps of the NEWS file in the repository (which I set to the git commit of the latest commit elsewhere) like this:

dist-hook: po-CreationDate-to-mtime-NEWS
.PHONY: po-CreationDate-to-mtime-NEWS
po-CreationDate-to-mtime-NEWS: mtime-NEWS-to-git-HEAD
  $(AM_V_GEN)for p in $(distdir)/po/*.po $(distdir)/po/$(PACKAGE).pot; do \
    if test -f "$$p"; then \
      $(SED) -e 's,POT-Creation-Date: .*\\n",POT-Creation-Date: '"$$(env LC_ALL=C TZ=UTC0 stat --format=%y $(srcdir)/NEWS   cut -c1-16,31-)"'\\n",' < $$p > $$p.tmp && \
      if cmp $$p $$p.tmp > /dev/null; then \
        rm -f $$p.tmp; \
      else \
        mv $$p.tmp $$p; \
      fi \
    fi \
  done

Similarily, I set a predictable modification time of the texinfo source file like this:

dist-hook: mtime-NEWS-to-git-HEAD
.PHONY: mtime-NEWS-to-git-HEAD
mtime-NEWS-to-git-HEAD:
  $(AM_V_GEN)if test -e $(srcdir)/.git \
                && command -v git > /dev/null; then \
    touch -m -t "$$(git log -1 --format=%cd \
      --date=format-local:%Y%m%d%H%M.%S)" $(srcdir)/NEWS; \
  fi

However I ve realized that this needs to happen earlier and probably has to be run during ./configure time, because the doc/version.texi file is generated on first build before running make dist and for some reason the file is not rebuilt at release time. The Automake texinfo integration is a bit inflexible about providing hooks to extend the dependency tracking. The method to address these differences isn t really important, and they change over time depending on preferences. What is important is that the differences are eliminated.

ChangeLog Traditionally ChangeLog files were manually prepared, and still is for some projects. I maintain git2cl but recently I ve settled with gnulib s gitlog-to-changelog because doing so avoids another build dependency (although the output formatting is different and arguable worse for my git commit style). So the ChangeLog files are generated from git history. This means a shallow clone will not produce the same ChangeLog file depending on how deep it was cloned. For Libntlm I simply disabled use of generated ChangeLog because I wanted to support an even more extreme form of reproducibility: I wanted to be able to reproduce the full make dist source archives from a minimal git-archive source archive. However for other projects I ve settled with a middle ground. I realized that for git describe to produce reproducible outputs, the shallow clone needs to include the last release tag. So it felt acceptable to assume that the clone is not minimal, but instead has some but not all of the history. I settled with the following recipe to produce ChangeLog's covering all changes since the last release.

dist-hook: gen-ChangeLog
.PHONY: gen-ChangeLog
gen-ChangeLog:
  $(AM_V_GEN)if test -e $(srcdir)/.git; then			\
    LC_ALL=en_US.UTF-8 TZ=UTC0					\
    $(top_srcdir)/build-aux/gitlog-to-changelog			\
       --srcdir=$(srcdir) --					\
       v$(PREV_VERSION)~.. > $(distdir)/cl-t &&			\
         printf '\n\nSee the source repo for older entries\n'	\
         >> $(distdir)/cl-t &&					\
         rm -f $(distdir)/ChangeLog &&				\
         mv $(distdir)/cl-t $(distdir)/ChangeLog;  		\
  fi

I m undecided about the usefulness of generated ChangeLog files within make dist archives. Before we have stable and secure archival of git repositories widely implemented, I can see some utility of this in case we lose all copies of the upstream git repositories. I can sympathize with the concept of ChangeLog files died when we started to generate them from git logs: the files no longer serve any purpose, and we can ask people to go look at the git log instead of reading these generated non-source files.

Long-term reproducible trusted build environment Distributions comes and goes, and old releases of them goes out of support and often stops working. Which build environment should I chose to build the official release archives? To my knowledge only Guix offers a reliable way to re-create an older build environment (guix gime-machine) that have bootstrappable properties for additional confidence. However I had two difficult problems here. The first one was that I needed Guix container images that were usable in GitLab CI/CD Pipelines, and this side-tracked me for a while. The second one delayed my effort for many months, and I was inclined to give up. Libidn distribute a C# implementation. Some of the C# source code files included in the release tarball are generated. By what? You guess it, by a C# program, with the source code included in the distribution. This means nobody could reproduce the source tarball of Libidn without trusting someone elses C# compiler binaries, which were built from binaries of earlier releases, chaining back into something that nobody ever attempts to build any more and likely fail to build due to bit-rot. I had two basic choices, either remove the C# implementation from Libidn (which may be a good idea for other reasons, since the C and C# are unrelated implementations) or build the source tarball on some binary-only distribution like Trisquel. Neither felt appealing to me, but a late christmas gift of a reproducible Mono came to Guix that resolve this.

Embedded images in Texinfo manual For Libidn one section of the manual has an image illustrating some concepts. The PNG, PDF and EPS outputs were generated via fig2dev from a *.fig file (hello 1985!) that I had stored in git. Over time, I had also started to store the generated outputs because of build issues. At some point, it was possible to post-process the PDF outputs with grep to remove some timestamps, however with compression this is no longer possible and actually the grep command I used resulted in a 0-byte output file. So my embedded binaries in git was no longer reproducible. I first set out to fix this by post-processing things properly, however I then realized that the *.fig file is not really easy to work with in a modern world. I wanted to create an image from some text-file description of the image. Eventually, via the Guix manual on guix graph, I came to re-discover the graphviz language and tool called dot (hello 1993!). All well then? Oh no, the PDF output embeds timestamps. Binary editing of PDF s no longer work through simple grep, remember? I was back where I started, and after some (soul- and web-) searching I discovered that Ghostscript (hello 1988!) pdfmarks could be used to modify things here. Cooperating with automake s texinfo rules related to make dist proved once again a worthy challenge, and eventually I ended up with a Makefile.am snippet to build images that could be condensed into:

info_TEXINFOS = libidn.texi
libidn_TEXINFOS += libidn-components.png
imagesdir = $(infodir)
images_DATA = libidn-components.png
EXTRA_DIST += components.dot
DISTCLEANFILES = \
  libidn-components.eps libidn-components.png libidn-components.pdf
libidn-components.eps: $(srcdir)/components.dot
  $(AM_V_GEN)$(DOT) -Nfontsize=9 -Teps < $< > $@.tmp
  $(AM_V_at)! grep %%CreationDate $@.tmp
  $(AM_V_at)mv $@.tmp $@
libidn-components.pdf: $(srcdir)/components.dot
  $(AM_V_GEN)$(DOT) -Nfontsize=9 -Tpdf < $< > $@.tmp
# A simple sed on CreationDate is no longer possible due to compression.
# 'exiftool -CreateDate' is alternative to 'gs', but adds ~4kb to file.
# Ghostscript add <1kb.  Why can't 'dot' avoid setting CreationDate?
  $(AM_V_at)printf '[ /ModDate ()\n  /CreationDate ()\n  /DOCINFO pdfmark\n' > pdfmarks
  $(AM_V_at)$(GS) -q -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=$@.tmp2 $@.tmp pdfmarks
  $(AM_V_at)rm -f $@.tmp pdfmarks
  $(AM_V_at)mv $@.tmp2 $@
libidn-components.png: $(srcdir)/components.dot
  $(AM_V_GEN)$(DOT) -Nfontsize=9 -Tpng < $< > $@.tmp
  $(AM_V_at)mv $@.tmp $@
pdf-recursive: libidn-components.pdf
dvi-recursive: libidn-components.eps
ps-recursive: libidn-components.eps
info-recursive: $(top_srcdir)/.version libidn-components.png

Surely this can be improved, but I m not yet certain in what way is the best one forward. I like having a text representation as the source of the image. I m sad that the new image size is ~48kb compared to the old image size of ~1kb. I tried using exiftool -CreateDate as an alternative to GhostScript, but using it to remove the timestamp added ~4kb to the file size and naturally I was appalled by this ignorance of impending doom.

Test reproducibility of tarball Again, you need to continuously test the properties you desire. This means building your project twice using different environments and comparing the results. I ve settled with a small GitLab CI/CD pipeline job that perform bit-by-bit comparison of generated make dist archives. It also perform bit-by-bit comparison of generated git-archive artifacts. See the Libidn2 .gitlab-ci.yml 0-compare job which essentially is:

0-compare:
  image: alpine:latest
  stage: repro
  needs: [ B-AlmaLinux8, B-AlmaLinux9, B-RockyLinux8, B-RockyLinux9, B-Trisquel11, B-Ubuntu2204, B-PureOS10, B-Debian11, B-Devuan5, B-Debian12, B-gcc, B-clang, B-Guix, R-Guix, R-Debian12, R-Ubuntu2404, S-Trisquel10, S-Ubuntu2004 ]
  script:
  - cd out
  - sha256sum */*.tar.* */*/*.tar.*   sort   grep    -- -src.tar.
  - sha256sum */*.tar.* */*/*.tar.*   sort   grep -v -- -src.tar.
  - sha256sum */*.tar.* */*/*.tar.*   sort   uniq -c -w64   sort -rn
  - sha256sum */*.tar.* */*/*.tar.*   grep    -- -src.tar.   sort   uniq -c -w64   grep -v '^      1 '
  - sha256sum */*.tar.* */*/*.tar.*   grep -v -- -src.tar.   sort   uniq -c -w64   grep -v '^      1 '
# Confirm modern git-archive tarball reproducibility
  - cmp b-almalinux8/src/*.tar.gz b-almalinux9/src/*.tar.gz
  - cmp b-almalinux8/src/*.tar.gz b-rockylinux8/src/*.tar.gz
  - cmp b-almalinux8/src/*.tar.gz b-rockylinux9/src/*.tar.gz
  - cmp b-almalinux8/src/*.tar.gz b-debian12/src/*.tar.gz
  - cmp b-almalinux8/src/*.tar.gz b-devuan5/src/*.tar.gz
  - cmp b-almalinux8/src/*.tar.gz r-guix/src/*.tar.gz
  - cmp b-almalinux8/src/*.tar.gz r-debian12/src/*.tar.gz
  - cmp b-almalinux8/src/*.tar.gz r-ubuntu2404/src/*v2.*.tar.gz
# Confirm old git-archive (export-subst but long git describe) tarball reproducibility
  - cmp b-trisquel11/src/*.tar.gz b-ubuntu2204/src/*.tar.gz
# Confirm really old git-archive (no export-subst) tarball reproducibility
  - cmp b-debian11/src/*.tar.gz b-pureos10/src/*.tar.gz
# Confirm 'make dist' generated tarball reproducibility
  - cmp b-almalinux8/*.tar.gz b-rockylinux8/*.tar.gz
  - cmp b-almalinux9/*.tar.gz b-rockylinux9/*.tar.gz
  - cmp b-pureos10/*.tar.gz b-debian11/*.tar.gz
  - cmp b-devuan5/*.tar.gz b-debian12/*.tar.gz
  - cmp b-trisquel11/*.tar.gz b-ubuntu2204/*.tar.gz
  - cmp b-guix/*.tar.gz r-guix/*.tar.gz
# Confirm 'make dist' from git-archive tarball reproducibility
  - cmp s-trisquel10/*.tar.gz s-ubuntu2004/*.tar.gz

Notice that I discovered that git archive outputs differ over time too, which is natural but a bit of a nuisance. The output of the job is illuminating in the way that all SHA256 checksums of generated tarballs are included, for example the libidn2 v2.3.8 job log:

$ sha256sum */*.tar.* */*/*.tar.*   sort   grep -v -- -src.tar.
368488b6cc8697a0a937b9eb307a014396dd17d3feba3881e6911d549732a293  b-trisquel11/libidn2-2.3.8.tar.gz
368488b6cc8697a0a937b9eb307a014396dd17d3feba3881e6911d549732a293  b-ubuntu2204/libidn2-2.3.8.tar.gz
59db2d045fdc5639c98592d236403daa24d33d7c8db0986686b2a3056dfe0ded  b-debian11/libidn2-2.3.8.tar.gz
59db2d045fdc5639c98592d236403daa24d33d7c8db0986686b2a3056dfe0ded  b-pureos10/libidn2-2.3.8.tar.gz
5bd521d5ecd75f4b0ab0fc6d95d444944ef44a84cad859c9fb01363d3ce48bb8  s-trisquel10/libidn2-2.3.8.tar.gz
5bd521d5ecd75f4b0ab0fc6d95d444944ef44a84cad859c9fb01363d3ce48bb8  s-ubuntu2004/libidn2-2.3.8.tar.gz
7f1dcdea3772a34b7a9f22d6ae6361cdcbe5513e3b6485d40100b8565c9b961a  b-almalinux8/libidn2-2.3.8.tar.gz
7f1dcdea3772a34b7a9f22d6ae6361cdcbe5513e3b6485d40100b8565c9b961a  b-rockylinux8/libidn2-2.3.8.tar.gz
8031278157ce43b5813f36cf8dd6baf0d9a7f88324ced796765dcd5cd96ccc06  b-clang/libidn2-2.3.8.tar.gz
8031278157ce43b5813f36cf8dd6baf0d9a7f88324ced796765dcd5cd96ccc06  b-debian12/libidn2-2.3.8.tar.gz
8031278157ce43b5813f36cf8dd6baf0d9a7f88324ced796765dcd5cd96ccc06  b-devuan5/libidn2-2.3.8.tar.gz
8031278157ce43b5813f36cf8dd6baf0d9a7f88324ced796765dcd5cd96ccc06  b-gcc/libidn2-2.3.8.tar.gz
8031278157ce43b5813f36cf8dd6baf0d9a7f88324ced796765dcd5cd96ccc06  r-debian12/libidn2-2.3.8.tar.gz
acf5cbb295e0693e4394a56c71600421059f9c9bf45ccf8a7e305c995630b32b  r-ubuntu2404/libidn2-2.3.8.tar.gz
cbdb75c38100e9267670b916f41878b6dbc35f9c6cbe60d50f458b40df64fcf1  b-almalinux9/libidn2-2.3.8.tar.gz
cbdb75c38100e9267670b916f41878b6dbc35f9c6cbe60d50f458b40df64fcf1  b-rockylinux9/libidn2-2.3.8.tar.gz
f557911bf6171621e1f72ff35f5b1825bb35b52ed45325dcdee931e5d3c0787a  b-guix/libidn2-2.3.8.tar.gz
f557911bf6171621e1f72ff35f5b1825bb35b52ed45325dcdee931e5d3c0787a  r-guix/libidn2-2.3.8.tar.gz

I m sure I have forgotten or suppressed some challenges (sprinkling LANG=C TZ=UTC0 helps) related to these goals, but my hope is that this discussion of solutions will inspire you to implement these concepts for your software project too. Please share your thoughts and additional insights in a comment below. Enjoy Happy Hacking in the course of practicing this!

Comparison of architecture and mainstream adoption potential

Protocol	Identity System	Example	Storage model	Cost for end users	Potential
Mastodon	Tied to server domain	@ottok@mastodon.social	Federated instances	Free (some instances charge)	High
Bluesky	Portable (DID)	ottoke.bsky.social	Federated instances	Free	Moderate
Farcaster	ENS (Ethereum)	@ottok	Blockchain + off-chain	Small gas fees	Moderate
Lens	NFT-based (Polygon)	@ottok	Blockchain + off-chain	Small gas fees	Niche
Nostr	Cryptographic Keys	npub16lc6uhqpg6dnqajylkhwuh3j7ynhcnje508tt4v6703w9kjlv9vqzz4z7f	Federated instances	Free (some instances charge)	Niche

1. Mastodon (ActivityPub) Mastodon was created in 2016 by Eugen Rochko, a German software developer who sought to provide a decentralized and user-controlled alternative to Twitter. It was built on the ActivityPub protocol, now standardized by W3C Social Web Working Group, to allow users to join independent servers while still communicating across the broader Mastodon network. Mastodon operates on a federated model, where multiple independently run servers communicate via ActivityPub. Each server sets its own moderation policies, leading to a decentralized but fragmented experience. The servers can alternatively be called instances, relays or nodes, depending on what vocabulary a protocol has standardized on.

• Identity: User identity is tied to the instance where they registered, represented as @username@instance.tld.
• Storage: Data is stored on individual instances, which federate messages to other instances based on their configurations.
• Cost: Free to use, but relies on instance operators willing to run the servers.

The protocol defines multiple activities such as:

• Creating a post
• Liking
• Sharing
• Following
• Commenting

Example Message in ActivityPub (JSON-LD Format)

json Copy

"@context": "https://www.w3.org/ns/activitystreams", "type": "Create", "actor": "https://mastodon.social/users/ottok", "object": "type": "Note", "content": "Hello from #Mastodon!", "published": "2025-03-03T12:00:00Z", "to": ["https://www.w3.org/ns/activitystreams#Public"]

 
 "@context": "https://www.w3.org/ns/activitystreams",
 "type": "Create",
 "actor": "https://mastodon.social/users/ottok",
 "object":  
 "type": "Note",
 "content": "Hello from #Mastodon!",
 "published": "2025-03-03T12:00:00Z",
 "to": ["https://www.w3.org/ns/activitystreams#Public"]
  
 

Servers communicate across different platforms by publishing activities to their followers or forwarding activities between servers. Standard HTTPS is used between servers for communication, and the messages use JSON-LD for data representation. The WebFinger protocol is used for user discovery. There is however no neat way for home server discovery yet. This means that if you are browsing e.g. Fosstodon and want to follow a user and press Follow, a dialog will pop up asking you to enter your own home server (e.g. mastodon.social) to redirect you there for actually executing the Follow action on with your account. Mastodon is open source under the AGPL at github.com/mastodon/mastodon. Anyone can operate their own instance. It just requires to run your own server and some skills to maintain a Ruby on Rails app with a PostgreSQL database backend, and basic understanding of the protocol to configure federation with other ActivityPub instances.

Popularity: Already established, but will it grow more? Mastodon has seen steady growth, especially after Twitter s acquisition in 2022, with some estimates stating it peaked at 10 million users across thousands of instances. However, its fragmented user experience and the complexity of choosing instances have hindered mainstream adoption. Still, it remains the most established decentralized alternative to Twitter. Note that Donald Trump s Truth Social is based on the Mastodon software but does not federate with the ActivityPub network. The ActivityPub protocol is the most widely used of its kind. One of the other most popular services is the Lemmy link sharing service, similar to Reddit. The larger ecosystem of ActivityPub is called Fediverse, and estimates put the total active user count around 6 million.

2. Bluesky (AT Protocol) Interestingly, Bluesky was conceived within Twitter in 2019 by Twitter founder Jack Dorsey. After being incubated as a Twitter-funded project, it spun off as an independent Public Benefit LLC in February 2022 and launched its public beta in February 2023. Bluesky runs on top of the Authenticated Transfer (AT) Protocol published at https://github.com/bluesky-social/atproto. The protocol enables portable identities and data ownership, meaning users can migrate between platforms while keeping their identity and content intact. In practice, however, there is only one popular server at the moment, which is Bluesky itself.

• Identity: Usernames are domain-based (e.g., @user.bsky.social).
• Storage: Content is theoretically federated among various servers.
• Cost: Free to use, but relies on instance operators willing to run the servers.

Example Message in AT Protocol (JSON Format)

json Copy

"repo": "did:plc:ottoke.bsky.social", "collection": "app.bsky.feed.post", "record": "$type": "app.bsky.feed.post", "text": "Hello from Bluesky!", "createdAt": "2025-03-03T12:00:00Z", "langs": ["en"]

 
 "repo": "did:plc:ottoke.bsky.social",
 "collection": "app.bsky.feed.post",
 "record":  
 "$type": "app.bsky.feed.post",
 "text": "Hello from Bluesky!",
 "createdAt": "2025-03-03T12:00:00Z",
 "langs": ["en"]
  
 

Popularity: Hybrid approach may have business benefits? Bluesky reported over 3 million users by 2024, probably getting traction due to its Twitter-like interface and Jack Dorsey s involvement. Its hybrid approach decentralized identity with centralized components could make it a strong candidate for mainstream adoption, assuming it can scale effectively.

3. Warpcast (Farcaster Network) Farcaster was launched in 2021 by Dan Romero and Varun Srinivasan, both former crypto exchange Coinbase executives, to create a decentralized but user-friendly social network. Built on the Ethereum blockchain, it could potentially offer a very attack-resistant communication medium. However, in my own testing, Farcaster does not seem to fully leverage what Ethereum could offer. First of all, there is no diversity in programs implementing the protocol as at the moment there is only Warpcast. In Warpcast the signup requires an initial 5 USD fee that is not payable in ETH, and users need to create a new wallet address on the Ethereum layer 2 network Base instead of simply reusing their existing Ethereum wallet address or ENS name. Despite this, I can understand why Farcaster may have decided to start out like this. Having a single client program may be the best strategy initially. One of the decentralized chat protocol Matrix founders, Matthew Hodgson, shared in his FOSDEM 2025 talk that he slightly regrets focusing too much on developing the protocol instead of making sure the app to use it is attractive to end users. So it may be sensible to ensure Warpcast gets popular first, before attempting to make the Farcaster protocol widely used. As a protocol Farcaster s hybrid approach makes it more scalable than fully on-chain networks, giving it a higher chance of mainstream adoption if it integrates seamlessly with broader Web3 ecosystems.

• Identity: ENS (Ethereum Name Service) domains are used as usernames.
• Storage: Messages are stored in off-chain hubs, while identity is on-chain.
• Cost: Users must pay gas fees for some operations but reading and posting messages is mostly free.

Example Message in Farcaster (JSON Format)

json Copy

"fid": 766579, "username": "ottok", "custodyAddress": "0x127853e48be3870172baa4215d63b6d815d18f21", "connectedWallet": "0x3ebe43aa3ae5b891ca1577d9c49563c0cee8da88", "text": "Hello from Farcaster!", "publishedAt": 1709424000, "replyTo": null, "embeds": []

 
 "fid": 766579,
 "username": "ottok",
 "custodyAddress": "0x127853e48be3870172baa4215d63b6d815d18f21",
 "connectedWallet": "0x3ebe43aa3ae5b891ca1577d9c49563c0cee8da88",
 "text": "Hello from Farcaster!",
 "publishedAt": 1709424000,
 "replyTo": null,
 "embeds": []
 

Popularity: Decentralized social media + decentralized payments a winning combo? Ethereum founder Vitalik Buterin (warpcast.com/vbuterin) and many core developers are active on the platform. Warpcast, the main client for Farcaster, has seen increasing adoption, especially among Ethereum developers and Web3 enthusiasts. I too have an profile at warpcast.com/ottok. However, the numbers are still very low and far from reaching network effects to really take off. Blockchain-based social media networks, particularly those built on Ethereum, are compelling because they leverage existing user wallets and persistent identities while enabling native payment functionality. When combined with decentralized content funding through micropayments, these blockchain-backed social networks could offer unique advantages that centralized platforms may find difficult to replicate, being decentralized both as a technical network and in a funding mechanism.

4. Hey.xyz (Lens Network) The Lens Protocol was developed by decentralized finance (DeFi) team Aave and launched in May 2022 to provide a user-owned social media network. While initially built on Polygon, it has since launched its own Layer 2 network called the Lens Network in February 2024. Lens is currently the main competitor to Farcaster. Lens stores profile ownership and references on-chain, while content is stored on IPFS/Arweave, enabling composability with DeFi and NFTs.

• Identity: Profile ownership is tied to NFTs on the Polygon blockchain.
• Storage: Content is on-chain and integrates with IPFS/Arweave (like NFTs).
• Cost: Users must pay gas fees for some operations but reading and posting messages is mostly free.

Example Message in Lens (JSON Format)

json Copy

"profileId": "@ottok", "contentURI": "ar://QmExampleHash", "collectModule": "0x23b9467334bEb345aAa6fd1545538F3d54436e96", "referenceModule": "0x0000000000000000000000000000000000000000", "timestamp": 1709558400

 
 "profileId": "@ottok",
 "contentURI": "ar://QmExampleHash",
 "collectModule": "0x23b9467334bEb345aAa6fd1545538F3d54436e96",
 "referenceModule": "0x0000000000000000000000000000000000000000",
 "timestamp": 1709558400
 

Popularity: Probably not as social media site, but maybe as protocol? The social media side of Lens is mainly the Hey.xyz website, which seems to have fewer users than Warpcast, and is even further away from reaching critical mass for network effects. The Lens protocol however has a lot of advanced features and it may gain adoption as the building block for many Web3 apps.

5. Primal.net (Nostr Network) Nostr (Notes and Other Stuff Transmitted by Relays) was conceptualized in 2020 by an anonymous developer known as fiatjaf. One of the primary design tenets was to be a censorship-resistant protocol and it is popular among Bitcoin enthusiasts, with Jack Dorsey being one of the public supporters. Unlike the Farcaster and Lens protocols, Nostr is not blockchain-based but just a network of relay servers for message distribution. If does however use public key cryptography for identities, similar to how wallets work in crypto.

• Identity: Public-private key pairs define identity (with prefix npub...).
• Storage: Content is federated among multiple servers, which in Nostr vocabulary are called relays.
• Cost: No gas fees, but relies on relay operators willing to run the servers.

Example Message in Nostr (JSON Format)

json Copy

"id": "note1xyz...", "pubkey": "npub1...", "kind": 1, "content": "Hello from Nostr!", "created_at": 1709558400, "tags": [], "sig": "sig1..."

 
 "id": "note1xyz...",
 "pubkey": "npub1...",
 "kind": 1,
 "content": "Hello from Nostr!",
 "created_at": 1709558400,
 "tags": [],
 "sig": "sig1..."
 

Popularity: If Jack Dorsey and Bitcoiners promote it enough? Primal.net as a web app is pretty solid, but it does not stand out much. While Jack Dorsey has shown support by donating $1.5 million to the protocol development in December 2021, its success likely depends on broader adoption by the Bitcoin community.

Will any of these replace X/Twitter? As usage patterns vary, the statistics are not fully comparable, but this overview of the situation in March 2025 gives a decent overview.

Platform	Total Accounts	Active Users	Growth Trend
Mastodon	~10 million	~1 million	Steady
Bluesky	~33 million	~1 million	Steady
Nostr	~41 million	~20 thousand	Steady
Farcaster	~850 thousand	~50 thousand	Flat
Lens	~140 thousand	~20 thousand	Flat

Mastodon and Bluesky have already reached millions of users, while Lens and Farcaster are growing within crypto communities. It is however clear that none of these are anywhere close to how popular X/Twitter is. In particular, Mastodon had a huge influx of users in the fall of 2022 when Twitter was acquired, but to challenge the incumbents the growth would need to significantly accelerate. We can all accelerate this development by embracing decentralized social media now alongside existing dominant platforms. Who knows, given the right circumstances maybe X.com leadership decides to change the operating model and start federating contents to break out from a walled garden model. The likelyhood of such development would increase if decentralized networks get popular, and the encumbents feel they need to participate to not lose out.

Past and future The idea of decentralized social media is not new. One early pioneer identi.ca launched in 2008, only two years after Twitter, using the OStatus protocol to promote decentralization. A few years later it evolved into pump.io with the ActivityPump protocol, and also forked into GNU Social that continued with OStatus. I remember when these happened, and that in 2010 also Diaspora launched with fairly large publicity. Surprisingly both of these still operate (I can still post both on identi.ca and diasp.org), but the activity fizzled out years ago. The protocol however survived partially and evolved into ActivityPub, which is now the backbone of the Fediverse. The evolution of decentralized social media over the next decade will likely parallel developments in democracy, freedom of speech and public discourse. While the early 2010s emphasized maximum independence and freedom, the late 2010s saw growing support for content moderation to combat misinformation. The AI era introduces new challenges, potentially requiring proof-of-humanity verification for content authenticity. Key factors that will determine success:

• User experience and ease of onboarding
• Network effects and critical mass of users
• Integration with existing web3 infrastructure
• Balance between decentralization and usability
• Sustainable economic models for infrastructure

This is clearly an area of development worth monitoring closely, as the next few years may determine which protocol becomes the de facto standard for decentralized social communication.

• Local campus press release - Computing institute press release - Engineering institute press release - Federal institute press release - Debian-br-eventos email Below you can check the list of talks.

uefi =   version = "0.33", features = ["panic_handler", "alloc", "global_allocator"]  

[toolchain]
targets = ["aarch64-unknown-uefi", "x86_64-unknown-uefi"]

$ convert -resize 1280x900 kier.jpg kier.full.jpg
$ convert -depth 8 kier.full.jpg rgba:kier.bin

const KIER: &[u8] = include_bytes!("../kier.bin");
const KIER_WIDTH: usize = 1280;
const KIER_HEIGHT: usize = 641;
const KIER_PIXEL_SIZE: usize = 4;

/// RGB Image to move around. This isn't the same as an
///  image::RgbImage , but we can associate the size of
/// the image along with the flat buffer of pixels.
struct RgbImage  
/// Size of the image as a tuple, as the
 /// (width, height)
 size: (usize, usize),
/// raw pixels we'll send to the display.
 inner: Vec<BltPixel>,
 
impl RgbImage  
/// Create a new  RgbImage .
 fn new(width: usize, height: usize) -> Self  
RgbImage  
size: (width, height),
inner: vec![BltPixel::new(0, 0, 0); width * height],
 
 
/// Take our pixels and request that the UEFI GOP
 /// display them for us.
 fn write(&self, gop: &mut GraphicsOutput) -> Result  
gop.blt(BltOp::BufferToVideo  
buffer: &self.inner,
src: BltRegion::Full,
dest: (0, 0),
dims: self.size,
 )
 
 
impl Index<(usize, usize)> for RgbImage  
type Output = BltPixel;
fn index(&self, idx: (usize, usize)) -> &BltPixel  
let (x, y) = idx;
&self.inner[y * self.size.0 + x]
 
 
impl IndexMut<(usize, usize)> for RgbImage  
fn index_mut(&mut self, idx: (usize, usize)) -> &mut BltPixel  
let (x, y) = idx;
&mut self.inner[y * self.size.0 + x]
 
 

fn praise() -> Result  
let gop_handle = boot::get_handle_for_protocol::<GraphicsOutput>()?;
let mut gop = boot::open_protocol_exclusive::<GraphicsOutput>(gop_handle)?;
// Get the (width, height) that is the minimum of
 // our image and the display we're using.
 let (width, height) = gop.current_mode_info().resolution();
let (width, height) = (width.min(KIER_WIDTH), height.min(KIER_HEIGHT));
let mut buffer = RgbImage::new(width, height);
for y in 0..height  
for x in 0..width  
let idx_r = ((y * KIER_WIDTH) + x) * KIER_PIXEL_SIZE;
let pixel = &mut buffer[(x, y)];
pixel.red = KIER[idx_r];
pixel.green = KIER[idx_r + 1];
pixel.blue = KIER[idx_r + 2];
 
 
buffer.write(&mut gop)?;
Ok(())
 

#[entry]
fn main() -> Status  
uefi::helpers::init().unwrap();
praise().unwrap();
boot::stall(100_000_000);
Status::SUCCESS
 

$ cargo build --release --target x86_64-unknown-uefi

Testing the UEFI Blob While I can definitely get my machine to boot these blobs to test, I figured I d save myself some time by using QEMU to test without a full boot. If you ve not done this sort of thing before, we ll need two packages, qemu and ovmf. It s a bit different than most invocations of qemu you may see out there so I figured it d be worth writing this down, too.

$ doas apt install qemu-system-x86 ovmf

qemu has a nice feature where it ll create us an EFI partition as a drive and attach it to the VM off a local directory so let s construct an EFI partition file structure, and drop our binary into the conventional location. If you haven t done this before, and are only interested in running this in a VM, don t worry too much about it, a lot of it is convention and this layout should work for you.

$ mkdir -p esp/efi/boot
$ cp target/x86_64-unknown-uefi/release/*.efi \
 esp/efi/boot/bootx64.efi

With all this in place, we can kick off qemu, booting it in UEFI mode using the ovmf firmware, attaching our EFI partition directory as a drive to our VM to boot off of.

$ qemu-system-x86_64 \
 -enable-kvm \
 -m 2048 \
 -smbios type=0,uefi=on \
 -bios /usr/share/ovmf/OVMF.fd \
 -drive format=raw,file=fat:rw:esp

If all goes well, soon you ll be met with the all knowing gaze of Chosen One, Kier Eagan. The thing that really impressed me about all this is this program worked first try it all went so boringly normal. Truly, kudos to the uefi crate maintainers, it s incredibly well done.

Booting a live system Sure, we could stop here, but anyone can open up an app window and see a picture of Kier Eagan, so I knew I needed to finish the job and boot a real machine up with this. In order to do that, we need to format a USB stick. BE SURE /dev/sda IS CORRECT IF YOU RE COPY AND PASTING. All my drives are NVMe, so BE CAREFUL if you use SATA, it may very well be your hard drive! Please do not destroy your computer over this.

$ doas fdisk /dev/sda
Welcome to fdisk (util-linux 2.40.4).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1):
First sector (2048-4014079, default 2048):
Last sector, +/-sectors or +/-size K,M,G,T,P  (2048-4014079, default 4014079):
Created a new partition 1 of type 'Linux' and of size 1.9 GiB.
Command (m for help): t
Selected partition 1
Hex code or alias (type L to list all): ef
Changed type of partition 'Linux' to 'EFI (FAT-12/16/32)'.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

Once that looks good (depending on your flavor of udev you may or may not need to unplug and replug your USB stick), we can go ahead and format our new EFI partition (BE CAREFUL THAT /dev/sda IS YOUR USB STICK) and write our EFI directory to it.

$ doas mkfs.fat /dev/sda1
$ doas mount /dev/sda1 /mnt
$ cp -r esp/efi /mnt
$ find /mnt
/mnt
/mnt/efi
/mnt/efi/boot
/mnt/efi/boot/bootx64.efi

Of course, naturally, devotion to Kier shouldn t mean backdooring your system. Disabling Secure Boot runs counter to the Core Principals, such as Probity, and not doing this would surely run counter to Verve, Wit and Vision. This bit does require that you ve taken the step to enroll a MOK and know how to use it, right about now is when we can use sbsign to sign our UEFI binary we want to boot from to continue enforcing Secure Boot. The details for how this command should be run specifically is likely something you ll need to work out depending on how you ve decided to manage your MOK.

$ doas sbsign \
 --cert /path/to/mok.crt \
 --key /path/to/mok.key \
 target/x86_64-unknown-uefi/release/*.efi \
 --output esp/efi/boot/bootx64.efi

I figured I d leave a signed copy of boot2kier at /boot/efi/EFI/BOOT/KIER.efi on my Dell XPS 13, with Secure Boot enabled and enforcing, just took a matter of going into my BIOS to add the right boot option, which was no sweat. I m sure there is a way to do it using efibootmgr, but I wasn t smart enough to do that quickly. I let er rip, and it booted up and worked great! It was a bit hard to get a video of my laptop, though but lucky for me, I have a Minisforum Z83-F sitting around (which, until a few weeks ago was running the annual http server to control my christmas tree ) so I grabbed it out of the christmas bin, wired it up to a video capture card I have sitting around, and figured I d grab a video of me booting a physical device off the boot2kier USB stick.

Attentive readers will notice the image of Kier is smaller then the qemu booted system which just means our real machine has a larger GOP display resolution than qemu, which makes sense! We could write some fancy resize code (sounds annoying), center the image (can t be assed but should be the easy way out here) or resize the original image (pretty hardware specific workaround). Additionally, you can make out the image being written to the display before us (the Minisforum logo) behind Kier, which is really cool stuff. If we were real fancy we could write blank pixels to the display before blitting Kier, but, again, I don t think I care to do that much work.

But now I must away If I wanted to keep this joke going, I d likely try and find a copy of the original video when Helly 100%s her file and boot into that or maybe play a terrible midi PC speaker rendition of Kier, Chosen One, Kier after rendering the image. I, unfortunately, don t have any friends involved with production (yet?), so I reckon all that s out for now. I ll likely stop playing with this the joke was done and I m only writing this post because of how great everything was along the way. All in all, this reminds me so much of building a homebrew kernel to boot a system into but like, good, though, and it s a nice reminder of both how fun this stuff can be, and how far we ve come. UEFI protocols are light-years better than how we did it in the dark ages, and the tooling for this is SO much more mature. Booting a custom UEFI binary is miles ahead of trying to boot your own kernel, and I can t believe how good the uefi crate is specifically. Praise Kier! Kudos, to everyone involved in making this so delightful .

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. If you like this or other open-source work I do, you can sponsor me at GitHub.

Debian LTS contributors In January, 20 contributors have been paid to work on Debian LTS, their reports are available:

• Abhijith PA did 8.0h (out of 14.0h assigned), thus carrying over 6.0h to the next month.
• Adrian Bunk did 36.5h (out of 47.75h assigned and 52.25h from previous period), thus carrying over 63.5h to the next month.
• Andrej Shadura did 11.0h (out of 11.0h assigned and 4.0h from previous period), thus carrying over 4.0h to the next month.
• Arturo Borrero Gonzalez did 9.0h (out of 10.0h assigned), thus carrying over 1.0h to the next month.
• Bastien Roucari s did 22.0h (out of 22.0h assigned).
• Ben Hutchings did 8.0h (out of 21.0h assigned and 3.0h from previous period), thus carrying over 16.0h to the next month.
• Chris Lamb did 18.0h (out of 18.0h assigned).
• Daniel Leidert did 20.0h (out of 23.0h assigned and 3.0h from previous period), thus carrying over 6.0h to the next month.
• Emilio Pozuelo Monfort did 34.0h (out of 7.0h assigned and 27.75h from previous period), thus carrying over 0.75h to the next month.
• Guilhem Moulin did 3.25h (out of 20.0h assigned), thus carrying over 16.75h to the next month.
• Jochen Sprickerhof did 23.0h (out of 15.0h assigned and 8.0h from previous period).
• Lee Garrett did 15.75h (out of 8.5h assigned and 51.5h from previous period), thus carrying over 44.25h to the next month.
• Lucas Kanashiro did 8.0h (out of 32.0h assigned and 32.0h from previous period), thus carrying over 56.0h to the next month.
• Markus Koschany did 40.0h (out of 40.0h assigned).
• Roberto C. S nchez did 14.75h (out of 13.5h assigned and 10.5h from previous period), thus carrying over 9.25h to the next month.
• Santiago Ruano Rinc n did 21.75h (out of 18.75h assigned and 6.25h from previous period), thus carrying over 3.25h to the next month.
• Sean Whitton did 8.5h (out of 8.5h assigned).
• Sylvain Beucler did 10.5h (out of 0.0h assigned and 49.5h from previous period), thus carrying over 39.0h to the next month.
• Thorsten Alteholz did 11.0h (out of 11.0h assigned).
• Tobias Frost did 12.0h (out of 12.0h assigned).

Evolution of the situation In January, we have released 33 DLAs. There were numerous security and non-security updates to Debian 11 (codename bullseye ) during January.

• Notable security updates:
  • rsync, prepared by Thorsten Alteholz, fixed several CVEs (including information leak and path traversal vulnerabilities)
  • tomcat9, prepared by Markus Koschany, fixed several CVEs (including denial of service and information disclosure vulnerabilities)
  • ruby2.7, prepared by Bastien Roucari s, fixed several CVEs (including denial of service vulnerabilities)
  • tiff, prepared by Adrian Bunk, fixed several CVEs (including NULL ptr, buffer overflow, use-after-free, and segfault vulnerabilities)
• Notable non-security updates:
  • linux-6.1, prepared by Ben Hutchings, has been packaged for bullseye (this was done specifically to provide a supported upgrade path for systems that currently use kernel packages from the bullseye-backports suite)
  • debian-security-support, prepared by Santiago Ruano Rinc n, which formalized the EOL of intel-mediasdk and node-matrix-js-sdk

In addition to the security and non-security updates targeting bullseye , various LTS contributors have prepared uploads targeting Debian 12 (codename bookworm ) with fixes for a variety of vulnerabilities. Abhijith PA prepared an upload of puma; Bastien Roucari s prepared an upload of node-postcss with fixes for data processing and denial of service vulnerabilities; Daniel Leidert prepared updates for setuptools, python-asyncssh, and python-tornado; Lee Garrett prepared an upload of ansible-core; and Guilhem Moulin prepared updates for python-urllib3, sqlparse, and opensc. Santiago Ruano Rinc n also worked on tracking and filing some issues about packages that need an update in recent releases to avoid regressions on upgrade. This relates to CVEs that were fixed in buster or bullseye, but remain open in bookworm. These updates, along with Santiago s work on identifying and tracking similar issues, underscore the LTS Team s commitment to ensuring that the work we do as part of LTS also benefits the current Debian stable release. LTS contributor Sean Whitton also prepared an upload of jinja2 and Santiago Ruano Rinc n prepared an upload of openjpeg2 for Debian unstable (codename sid ), as part of the LTS Team effort to assist with package uploads to unstable.

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