CLOCKSS

Developing a Library Digital Preservation Strategy

Matt Smithers — Wed, 22 Oct 2025 13:45:48 +0000

Digital scholarship is at the heart of today’s research and learning. Without a clear plan, valuable knowledge can slip away through format changes, platform shifts, technology failures, or simple aging. A library digital preservation strategy sets out what you’ll keep, how you’ll keep it safe, and who is responsible - so the scholarly record you steward stays accessible, usable, and trustworthy for your researchers and community, now and into the future.

Getting started
A preservation strategy is a simple plan that says what you’ll keep, how you’ll keep it safe, and who does what - so people can still read and reuse your content years from now. This page walks you through the essentials in plain language and shows where CLOCKSS fits in.

Why have a strategy?
Before choosing tools or vendors, be clear on why you’re preserving. Purpose keeps the work focused and makes it easy to explain to colleagues funders, and other stakeholders.

Keep access going: If a platform change goes wrong or a publisher closes, your readers aren’t stranded.
Show you’re trustworthy: Authors and readers can see a clear plan, and evidence that you safeguard their interests.
Work smarter: Agreed rules stop one-off decisions and endless changes.
Reduce risk: You address obsolescence, vendor lock-in, and rights issues up front.

Build your strategy in 10 simple steps
Use these steps as your starter template. Each step has a brief explanation and a small set of actions - no jargon required. (This is where the NASIG model digital preservation policy fits - see below.)

1) Set your goals (why preserve?)
Goals are your north star - start with 2 or 3 short statements everyone can remember.

“Keep long-term access to published articles, books and related files (figures, data, code).”

“Ensure continuity of access despite shifts in national policies and priorities.”

2) Decide the scope (what’s in / what’s out)
Scope stops scope creep. Say clearly what you’ll preserve now, and what you won’t -plus why.

Include: Publications (PDF, HTML, XML, EPUB), digitised files,, datasets & code, images/audio/video, and key metadata (DOIs, ORCIDs, RORs).
Exclude (and say why): Preliminary analyses or “throwaway” datasets that were later replaced by higher-quality versions., routine communications such as email exchanges or meeting notes about project logistics., or anything you don’t have rights to keep yet.

3) Make a quick inventory (what you have, where it lives)
A lightweight list gives you visibility without creating bureaucracy.

List main content groups, where files are stored, who owns them, and file types.
Mark priority content (high value or at risk), e.g., disseminated by small publishers or unique datasets.

4) Assign roles (who does what)
Named people = real accountability.

For selection, rights checks, transfer, ingest, integrity checks, monitoring, reporting, and incident response, name:
- A lead person and a back-up (so you aren’t dependent on one person).

5) Set short, simple policies (the rules)
One page per topic is enough to start; you can expand later.

Selection & appraisal: how you choose and review priorities.
File formats: keep originals; create preservation copies like PDF/A where useful.
Metadata: DOI, creators + ORCID, licence, relationships.
Integrity (checksums): create on arrival; re-check on a schedule.
Access & rights: what you can share and when (e.g., during a platform outage).
Security & recovery: who can access files; how quickly you can restore.

6) Map your workflow (how the work flows)
A simple “happy path” prevents confusion and delays.

Identify & authorise content preservation
Transfer files (API/SFTP/export) with a file list
Validate (virus scan; basic checks; verify the checksum)
Ingest into your repository/preservation system
Replicate to another, independent trusted archive
Monitor jobs and scheduled integrity checks
Report monthly (what came in, what passed, any issues)

7) Choose storage & partners (avoid single points of failure)
Resilience comes from independence and diversity - more than one copy, place, and technology.

Keep important content in at least three different preservation services with different funding, governance, and technologies.
Pair your internal systems with an independent, community-governed dark archive for disaster-level risks and platform changes. (This is where CLOCKSS fits - see below.)

8) Plan time and money (sustainability)
Preservation is a practice, not a project. Budget for it.

Make a simple 3-year view of people, time, storage, memberships, and audits.
Set up a small steering group (library /IT/research office) that meets quarterly.

9) Set a few measures (prove it works)
A handful of metrics keeps you honest and shows progress.

Time from publication to “preserved copy.”
% of files with a recent checksum.
% of titles protected by an independent archive.

10) Improve steadily (don’t set-and-forget)
Small, regular improvements beat big, rare overhauls.

Review priorities each quarter.
Run one restore drill per year for each big content type (text, AV, data).
Fix gaps and update policies as you learn.

Common pitfalls (and easy fixes)
Most problems are predictable. Here’s how to dodge them without fuss.

“Backups = preservation.” Backups restore systems; preservation restores content even if the original system/vendor is gone. Use both.
“Cloud services = preservation.” Cloud storage is like renting space in someone else’s filing cabinet. You can put your files there, share them, and get them back easily but if you stop paying, the company changes, or a file gets deleted, it’s gone.
Enabling access to the preserved master copy. The preserved version is the master copy we keep safe for the long term. The access version is the user-friendly copy we share for viewing or download. They come from the same source, but serve different purposes: one protects, the other provides access.
Rights gaps. Make sure contracts explicitly allow/require preservation and open access if the source disappears.
Relying on one vendor or location. Always have an independent preservation copy (see CLOCKSS).

How to get started (a small, clear plan)
Have a look at the NASIG Model Digital Preservation Policy: https://nasig.org/NASIG-model-digital-preservation-policy It’s a friendly friend!

Start small, learn fast, and scale. Here’s a 12-week outline you can actually follow.

Weeks 1–2 - Foundations

Choose a pilot (e.g., one journal list or one digitised collection).
Write 1 page of Goals & Scope and 1 page of Roles & Workflow.
Make a simple inventory (what, where, who, formats).

Weeks 3–6 - Make it real

Publish short policies: Formats, Metadata, Integrity, Access & Rights.
Automate file transfer + checksum validation for the pilot.
Start a monthly preservation report.

Weeks 6–12 - Build resilience

Add a second, independent preservation copy — this is where CLOCKSS comes in.
Run a restore test and document the steps and timing.
Expand the scope based on what you learned.

Where CLOCKSS fits (and why include it)
Your strategy needs an independent safety net. CLOCKSS is purpose-built to be that safety net for scholarship.

Independent assurance: CLOCKSS is a not-for-profit, community-governed dark archive that protects the scholarly record beyond any single business, country, or platform.
Global, resilient network: Content is preserved across multiple locations with regular integrity checks.
Trigger access when needed: If the original source goes away, CLOCKSS provides open access so your readers aren’t left without content.
Easy to plug in: We work with your publishers and platforms to set up feeds, verify ingest, and give you the evidence your stakeholders expect.

Next step: Building or refreshing your preservation strategy?
Bring CLOCKSS in as your independent layer.
Let’s map your content and set up a right-sized onboarding.

Tiny glossary (for beginners)
A few quick definitions to de-jargon the process.

Checksum (fixity): A digital fingerprint; re-checking it tells you a file hasn’t changed or corrupted.
Dark archive: A preserved copy that stays closed unless specific conditions happen (e.g., the source disappears).
PDF/A: A long-term, preservation-friendly version of PDF.
DOI / ORCID: Persistent IDs for publications and researchers.

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Our Sustainability Journey: CLOCKSS and Carbon Footprint Tracking

Matt Smithers — Thu, 04 Sep 2025 14:34:58 +0000

In July 2023, CLOCKSS began a 15-month journey to better understand the environmental impact of our long-term digital preservation service. While our mission is to safeguard scholarly content for future generations, we recognize that sustainability must also guide how we operate. We're now sharing a high-level analysis of our carbon footprint, and some important lessons we’ve learned.

We started by forming a project team and partnering with experts from DIMPACT, who specialize in helping digital organizations assess and reduce their climate impact. Our first step was a two-hour workshop to map how content flows through the CLOCKSS system: how it’s ingested, preserved, and accessed. This workshop focused on digging deep into how CLOCKSS really works. How is content ingested, stored, and served? How do administrators and users interact with preserved content before and after it enters the archive? From this, we created a rough map of our content flow: into, around, and out of the CLOCKSS archive. The workshop also helped us visualize our infrastructure and create a working model of the archive.

A second workshop refined this model, identifying the actual machines involved in service delivery, where each is located, and what each one does and how often. This was a bit of a revelation as no one had a complete understanding of all the distributed kit we use to deliver the archive. There were unexpected benefits of this cross-organizational alignment – for example it helped us update our corporate asset register and strengthened shared understanding across the various research organizations that host CLOCKSS machines.

Next, we agreed on a set of data points to collect. Given CLOCKSS is hosted at 12 global sites, we focused on gathering data at four locations: University of Edinburgh, University of Alberta, Stanford University, and Indiana University.

Each site offered unique insights. For example:

Stanford, located in a region with a strong renewable energy mix, had good data availability and is well along its clean energy transition.
Indiana, located in a region heavily reliant on fossil fuels and where CLOCKSS machines are deeply integrated into a high-performance computing environment, proved more complex, but the process sparked important conversations about sustainability.

We plugged the data into a modelling spreadsheet and estimate that CLOCKSS generates about 9 tonnes of carbon per month from its archiving service and another 1 tonne per year from travel. Integrity checking, a key process ensuring content authenticity, is our most carbon-intensive operation. Notably, this estimate covers only the use phase of our hardware. We haven't yet quantified the embodied emissions, the environmental cost of producing our servers which will add to our overall footprint. We have got insight into the environmental cost of disposal, with host institutions having an array of thoughtful policies.

We presented our findings at iPRES 2024, the leading international digital preservation conference, where peer feedback will help us generalize the CLOCKSS model for broader application across the preservation community. This work is now underway under the auspices of the Digital Preservation Coalition’s new Carbon Footprint Taskforce.

This project wasn’t easy. It required sustained collaboration, deep inquiry, a lot of tenacious data gathering, and real organizational effort. But it was worth it. We now have clearer insights that will inform future decisions such as how many content copies we store, where we locate nodes, and other ways we can help to decrease our impact on the climate and environment.

As stewards of the scholarly record, we must preserve not just knowledge, but also the world that future scholars will inhabit.

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New Pilot: Diamond Open Access

Matt Smithers — Thu, 04 Sep 2025 14:00:47 +0000

CLOCKSS is proud to launch a pilot program to preserve Diamond Open Access publications - at no cost to participating libraries, whether current supporters or new to our community.

Diamond OA journals, published without author or reader fees, play a vital role in inclusive, community-driven scholarship. Yet, many lack the resources for long-term digital preservation. This initiative addresses that gap, ensuring these valuable contributions remain accessible, discoverable, and secure for future generations.

For our current library partners and those considering becoming CLOCKSS supporters, this pilot showcases the tangible value of your investment. By supporting CLOCKSS, you help preserve a critical segment of open scholarship while reinforcing an equitable and resilient publishing landscape. Your participation not only secures the future of Diamond journals—it affirms a shared commitment to protecting diverse, high-quality research as a public good.

For more information please see:

Supporting Libraries

If you have questions or want to know more? Contact us below:

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Preserving Knowledge for the Future: Libraries, Digital Infrastructure, and Ethical Stewardship

Matt Smithers — Thu, 24 Jul 2025 08:04:08 +0000

Insights from a Webinar with Roxanne Massingham (ANU) and Alicia Wise (CLOCKSS)

In an age of rapid technological transformation and an ever-expanding digital scholarly landscape, the question of how we preserve the integrity, accessibility, and diversity of knowledge has never been more pressing. This was the central focus of a recent webinar featuring Roxanne Missingham, University Librarian at the Australian National University (ANU), and Alicia Wise, Executive Director of CLOCKSS. Together, they unpacked the complex responsibilities libraries now face, not only in safeguarding the scholarly record, but also in reimagining their role as active participants in the creation and ethical stewardship of knowledge.

CLOCKSS, as Alicia explained, is a unique digital preservation network that operates globally, with a presence on five continents and participation from leading academic institutions. Its purpose is to protect scholarly content in a distributed, secure, and redundant way, ensuring that the knowledge we rely on today remains accessible and intact far into the future. The initiative is deeply values-driven, committed to principles of equity, resilience, and sustainability, and designed to function independently of corporate interests. CLOCKSS ensures that content is preserved in its original form, unaltered, to maintain the authenticity of the scholarly record.

For ANU, collaboration with CLOCKSS is not just a practical choice, it’s an expression of its identity and mission. As the only Commonwealth university in Australia, ANU carries a legislated responsibility to preserve and share knowledge for the nation and the broader Asia-Pacific region. Roxanne emphasized that preservation is a natural extension of this mission, particularly as libraries like ANU’s increasingly host, support, and partner in the publication of scholarship that doesn’t pass through traditional commercial publishing channels. This includes the rise of diamond open access journals and faculty-led publications, many of which are run with passion but limited infrastructure. CLOCKSS provides a sustainable and inclusive model to ensure these smaller, community-based publishing efforts are not lost to time or neglect.

Yet the conversation didn’t stop at technical infrastructure. Both Roxanne and Alicia stressed the urgent need to reframe preservation as an ethical and inclusive practice. Digital archives must serve all communities, not just those historically well-represented in scholarship. CLOCKSS and ANU are actively working to decolonize the scholarly record by elevating underrepresented voices, from Indigenous and LGBTQ+ researchers to Spanish-speaking and African scholars. This inclusive preservation work is essential if we are to build a digital future that reflects the full diversity of global knowledge.

At the same time, new threats are emerging. The growing capabilities of generative AI and the uncertainty surrounding digital copyright law are causing deep concern among creators, particularly around how their work might be scraped, repurposed, or misused without consent. Roxanne highlighted how existing copyright regimes, have failed to provide clarity or confidence. In response, libraries must lead new conversations with creators and institutions about how to develop content management frameworks that protect both access and agency. Librarians have long championed open access, but open doesn’t mean unprotected. There is a vital role to play in ensuring that creators’ rights are respected, and that ethical controls are in place to guide how research is shared, cited, and reused.

This is especially relevant as universities begin to experiment with hybrid models of scholarly publishing that are part repository, part publisher, and increasingly led by libraries. Roxanne pointed to Australia’s National E-Deposit Scheme as a strong model for commercial publications but emphasized the need to develop similar controls and support systems for university-based research outputs. These models must go beyond simply providing access; they must also address how institutions and libraries take long-term responsibility for the works they help bring into the world.

Alicia reinforced the point that while access is important, preservation is foundational and often invisible. Even though 75% of journals are preserved in at least one place, only a small fraction are secured in three or more, which makes the majority highly vulnerable. For books, there is not even a reliable international infrastructure to determine what is being preserved and where. The KEEPERS Registry (https://keepers.issn.org/) attempts to address this gap for journals by tracking archival activity across trusted preservation agencies, but no comparable system currently exists for books, leaving their long-term availability uncertain.

Digital content stored in only one location is at risk, and digital data is more fragile than many realize. Preserving bit-level integrity, redundancy, and authenticity requires careful, ongoing work, and yet it remains underfunded and underappreciated in many institutional strategies.

As a call to action, Alicia encouraged libraries to not only support centralized preservation efforts like CLOCKSS but also to share stewardship responsibilities with one another. Whether it's collaborating with a neighbouring institution or forming cross-border partnerships, distributed preservation is key to resilience. She invited libraries, publishers, and institutions to join the CLOCKSS community and take an active role in building a global preservation infrastructure that can support the entire scholarly ecosystem.

The webinar concluded with a reminder that digital preservation isn’t just a technical problem to be solved, it’s a collective ethical responsibility. Libraries are no longer just the gateways to information; they are its guardians. As scholarship continues to evolve, expanding beyond traditional formats, confronting new legal uncertainties, and navigating the rapid rise of AI—our systems of stewardship must evolve too. Preservation work may be quiet and often invisible, but it is foundational to the future of research, education, and informed public discourse. And in that future, libraries must not only protect knowledge but also help shape the way it is created, shared, and sustained.

To watch the full webinar, please visit our YouTube Channel

IPA Blasts Russian Attacks on Ukraine’s Publishing Sites

As a long-term digital preservation service committed to safeguarding scholarly and cultural content, CLOCKSS is here to help. We invite Ukrainian publishers, academic institutions, and libraries especially those whose digital content may be at risk due to war or instability to partner with us. We are prepared to preserve your materials securely, ensuring that they remain accessible to future generations.

If you or your organization needs support, please contact us at info@clockss.org

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IPA Blasts Russian Attacks on Ukraine’s Publishing Sites

Matt Smithers — Mon, 14 Jul 2025 12:04:52 +0000

At CLOCKSS, we were deeply saddened to read about the continuing attacks on Ukrainian publishing interests, as reported by Publishing Perspectives. The destruction of publishing houses, books, and libraries is not only a humanitarian tragedy—it is an assault on cultural memory and the right to knowledge.

IPA Blasts Russian Attacks on Ukraine’s Publishing Sites

If you or your organization needs support, please contact us at info@clockss.org

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How COUNTER Metrics and CLOCKSS Services Work Together to Support Open Access: Highlights from Our June 24th Webinar

Matt Smithers — Fri, 11 Jul 2025 08:44:06 +0000

On June 24th, we had the pleasure of hosting a dynamic webinar featuring Alicia Wise, Executive Director of CLOCKSS, and Tasha Mellins-Cohen, Executive Director of COUNTER, to explore how usage metrics and digital preservation services intersect to support a sustainable open access (OA) ecosystem. The session offered a deep dive into the complementary roles of COUNTER and CLOCKSS, touching on shared goals, common misconceptions, and the future of infrastructure support for OA content. Here are some key takeaways from our conversation:

COUNTER and the Importance of Transparent Metrics

Tasha emphasized that transparency and accountability are core to COUNTER’s mission. Usage data plays a vital role in evaluating the performance and value of open access publications. With standardization at its core, COUNTER ensures that usage statistics are comparable, trustworthy, and auditable - critical attributes for stakeholders making funding and publishing decisions. COUNTER’s work allows institutions to distinguish between genuine user engagement and artificial traffic, offering clarity in a fast-growing OA publishing environment.

CLOCKSS and the Role of Digital Preservation

Alicia highlighted that preservation is often overlooked until it’s too late. CLOCKSS addresses this by ensuring that academic content remains accessible in the long run - even if a publisher ceases operations or removes content from its platform. She explained that digital preservation builds trust with libraries and publishers, and in the OA model it plays an especially important role by fulfilling the promise of “open forever.” In a world where digital content is fragile and platforms evolve or disappear, CLOCKSS steps in to safeguard the scholarly record.

A Shared Mission: Complementary Roles for Open Access

While COUNTER focuses on how content is used today, and CLOCKSS ensures content is available tomorrow, both organizations work toward a common goal: strengthening the infrastructure that supports knowledge dissemination. Tasha and Alicia agreed that usage measurement and preservation are two sides of the same coin. COUNTER helps track the value of content, while CLOCKSS ensures that value is never lost. Together, they provide confidence to researchers, libraries, and funders that knowledge is both impactful and enduring.

Looking to the future, both leaders acknowledged the need for closer collaboration across infrastructure services. As the open infrastructure ecosystem grows, integrated approaches to metrics and preservation can reduce fragmentation and build resilience. Tasha and Alicia also identified sustainability and funding as shared challenges, emphasizing the importance of cross-sector support to maintain essential services like COUNTER and CLOCKSS.

The webinar shed light on how metrics and preservation - often seen as technical back-office functions - are, in fact, critical pillars key to open scholarly infrastructure. Through their complementary efforts, COUNTER and CLOCKSS help ensure that content is both measurable in its impact and guaranteed in its longevity.

If you missed the session or want to revisit the insights, you can find the recording on our YouTube Channel

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CERN: Library Science Talk Presentation Recording

Matt Smithers — Thu, 19 Jun 2025 15:31:18 +0000

Library Science Talk: Preserving Knowledge in a Shifting World: The Role of Libraries in Geopolitical Uncertainty

In this session, Alicia and Gali explored the vital role libraries play as guardians of knowledge, culture, and history—especially in times of geopolitical instability. As wars, political upheaval, and natural disasters increasingly threaten library collections, our presentation focused on the urgent need for robust preservation strategies. We highlighted real-world examples of cultural loss, including the destruction of over 200 libraries in Ukraine, the displacement of heritage materials during refugee crises, and the risks posed by censorship and ideological shifts. The talk emphasized the global responsibility to protect irreplaceable library resources and proposed ways the international community can work together to safeguard them for future generations via CLCOKSS.
The recording is available below:

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CLOCKSS triggers the Journal of Home Language Research

Alicia Wise — Wed, 11 Jun 2025 08:49:54 +0000

The Journal of Home Language Research (JHLR) was an international double-blind peer-reviewed open access journal that published original research from any part of the world in all areas related to the study of home languages. This included but was not limited to applied linguistics, theoretical linguistics, psychology, sociology and education. A home language is any language that was not the majority language spoken in the family and/or community.

It contains fascinating articles on such things as bilingualism, literacy skills acquisition during the Covid 19 pandemic, maternal labour in cultural and linguistic maintenance, and much more.

CLOCKSS was honored to be entrusted by Stockholm University Press with the long-term digital preservation of this journal, and we now make it available in perpetuity under a CC-BY license.

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The difference between a repository/platform with backup and preservation in an archive such as CLOCKSS.

Matt Smithers — Fri, 09 May 2025 08:05:11 +0000

Many people ask about the difference between using a repository or platform with backup and preserving content in an archive like CLOCKSS. While repositories and backups are essential for day-to-day access and recovery in case of technical issues, they don’t guarantee long-term preservation. CLOCKSS, on the other hand, is a trusted dark archive designed specifically for long-term digital preservation. It ensures scholarly content remains accessible for future generations, even if the original publisher can no longer provide access. See below for more details on these differences.

	Backup	Preservation
Primary Purpose	Data recovery	Long-term accessibility
Timeframe	Short-term	Long-term (potentially indefinite)
Focus	Ensuring data can be restored	Maintaining authenticity and usability over time
Technology	Standard storage systems	Dedicated preservation systems with higher redundancy, integrity checks, and disaster recovery
Management	Often automated, with defined schedules and retention policies	Requires ongoing management, monitoring, and eventually migration

In essence, backups are a crucial part of good practice in managing information, and preservation ensures the long-term availability of digital heritage and information. Both are vital to a healthy information ecosystem!

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Understanding CLOCKSS: A Commitment to Preserving Content Safely and Securely

Matt Smithers — Thu, 08 May 2025 13:44:30 +0000

Since the recent cyber-attack on the British Library, many publishers have reached out with questions about the security of their content. While we cannot disclose every detail of our security protocols, we want to assure you that we are dedicated to the long-term preservation and security of all content entrusted to us. Here is an overview of how CLOCKSS works to protect data and digital assets.

The CLOCKSS Mission: Long-Term Preservation and Access

At the heart of our work is a clear and unwavering mission: to ensure the long-term preservation and access of scholarly content. CLOCKSS is not simply another backup service; it’s a curated, authoritative copy of the original content. Our goal is to make sure that this content remains unchanged and protected—forever.

We understand the immense responsibility involved in preserving this material, and that’s why security is embedded in everything we do. Our use of the award-winning LOCKSS open-source preservation software, developed at Stanford University, is central to ensuring both the integrity and safety of this content.

The Role of LOCKSS Software in Our Security Framework

LOCKSS isn’t just about storing files; it’s about ensuring that content remains intact and protected against threats. The software is designed to actively manage content with bit-level integrity checking. This means that every piece of content entrusted to CLOCKSS is continuously monitored to ensure that nothing is tampered with or altered.

The LOCKSS system operates as a self-healing secure storage network, meaning that if any content is compromised—whether through corruption or unauthorized access—the system automatically detects and corrects the issue. This robust protection keeps content safe from exfiltration or subversion, ensuring it remains as it should be, for the long term.

If you'd like to learn more about how our preservation system works, you can read more in detail here.

Multi-Layered Security: Comprehensive and Adaptable

When it comes to securing the CLOCKSS archive, we take a layered approach. Security doesn’t just come from technology—it’s also embedded in governance, policy, and social practices. Some layers are well-documented in computer science literature , while others remain private for security reasons. Here are some key layers that protect CLOCKSS content:

1. Governance and Policy

CLOCKSS operates under the guidance of libraries and publishers worldwide, all of whom agree on policies that govern our practices. Our board includes representatives from organizations with in-house security expertise, and our team includes experts for whom security is always a top priority.

2. Secure Storage

All content in the CLOCKSS archive is stored in an actively managed, secure, distributed network of storage nodes. Each node is protected by a unique combination of security measures, offering a multi-faceted approach to securing the data.

3. Distributed Preservation

One of the core strengths of CLOCKSS is the distribution of content across 12 secure storage sites around the globe, hosted by universities and research institutes. This geographic diversity enhances security by reducing the risk of a single point of failure. These sites are in constant communication, so if any content becomes corrupted, it is quickly identified and repaired by other nodes in the network.

4. Diversity in Security Practices

Each of the 12 preservation sites is managed and protected in unique ways, adding an extra layer of defense. This diversity strengthens the security of the entire system, ensuring that no single vulnerability can compromise the entire archive.

5. Access Controls and Technical Security Measures

CLOCKSS operates as a dark archive, which means that content is protected and managed for long-term preservation and access, but it is not openly accessible to the public. This dark archive model significantly reduces human-related risks to security, such as accidental breaches or unauthorized access.

Security measures within the CLOCKSS archive include the use of SSL certificates, firewalls, network intrusion detection systems, physical security measures, and remote wiping capabilities. Additionally, we use encryption and strong authentication protocols to ensure only authorized users can administer the preservation of the content.

6. Regular Audits and Testing

We cannot afford to become complacent, which is why we conduct regular external audits and security tests to assess our defenses. For example, we conducted a series of penetration tests while temporarily removing certain security layers. Even without these layers, CLOCKSS withstood external attacks, proving the resilience of our systems.

7. Pre-Trigger Scans for Malware and Viruses

As a dark archive, CLOCKSS stores and manages files in a state that prevents them from being accessed or executed in a typical browsing environment. This means that if any content contains malware or viruses, these remain locked in a “fossilized” state where they cannot activate. Prior to triggering content for release, we perform special checks to ensure the content is free from such threats.

8. Accreditation and Recognition

CLOCKSS is accredited under the Center for Research Libraries’ TRAC Audit scheme, receiving the highest score ever awarded to a trusted repository. This accreditation considers everything from our technology and technical infrastructure to our security arrangements, validating the strength of our preservation and protection processes.

9. Adapting to Changing Threats

At CLOCKSS, we understand that security is not static—it must evolve in response to emerging threats. The team at Stanford University, led by Thib Guicherd-Callin, actively monitors vulnerabilities and takes immediate action to mitigate risks. For example, in December 2021, a major vulnerability called "PwnKit" affected all versions of Linux, including those used by CLOCKSS systems. We were able to patch all affected machines on the same day the vulnerability was announced, ensuring no exploits were able to spread.

Conclusion

CLOCKSS is more than just a repository — it's a secure, self-healing archival vault designed to preserve digital content for generations to come. Our multi-layered security practices, combined with cutting-edge technology and vigilant monitoring, ensure that the content we manage remains protected and secure.

As threats continue to evolve, CLOCKSS remains committed to adapting and strengthening our defenses.

References

Reich, V. A. (2002). Diffused Knowledge Immortalizes Itself. The LOCKSS Program. High Energy Physics Libraries Webzine, 7/2003.