Ten years ago, the concept of Schluss—a personal vault for storing your data—seemed almost silly. At that time, Google and Facebook were skyrocketing, and people were captivated by these platforms. “We thought ‘I have nothing to hide, everybody can know everything about me.’” Organisations viewed data as the new gold, recognising that as long as they maintained trust and provided appealing services, people would freely share even more of their personal information. Today, we understand the complexities and implications of data sharing much better. Schluss’ mission is to give you full control over your online data: no copies, only a secure vault containing the original information.
Marie-José Hoefmans, co-founder of Schluss, conveyed to us the Schluss mission, the challenges they face, and the collaboration with ALTEN Netherlands. Together, with the support of ALTEN, they intend to create the Schluss vault, to keep personal data safe.
Changing the Traditional Data-Sharing Landscape
In today’s digital world, our personal data is scattered across various databases, often without our knowledge or control. From medical records to financial details, this data is widely shared, duplicated, and repurposed, raising privacy concerns and making it difficult for individuals to manage their information. Addressing these issues, Schluss offers a transformative approach: a central, secure vault where an individual’s original data is stored, and no copies are made or shared elsewhere. “We’re giving people full control over their data on the internet”, allowing users to decide exactly who accesses their information, when, for how long, and for what purpose.
The Schluss solution changes the traditional data-sharing landscape. Instead of allowing companies to retain copies of users’ data in their own databases, Schluss lets organisations store necessary information directly in each user’s personal vault. This vault acts as a single source of truth, housing original data that can be viewed and, if necessary, corrected by request. “When organisations need access, they don’t take a copy, instead, they ‘knock at your door’—they ask for permission to view specific information from your vault, outlining the purpose and time frame for access.” By centralising data in a single, user-controlled vault, Schluss ensures accuracy and security and prioritises individual empowerment, allowing people to regain control over their digital information.
“Once there are copies of your data, there is no control anymore.”
Rethinking the Handling of Personal Data
One of the main challenges Schluss faces is helping organisations truly understand the radical shift their model brings. As Marie-José explains, this approach requires companies to rethink everything they know about handling personal data online. “I ask people to leave behind what they think they know about working with personal data. Then I ask, ‘What would it look like if you had full control over your own data?’” This mindset shift is difficult for organisations that are accustomed to traditional data practices and centralised storage, which hold significant security risks and regulatory burdens. Schluss advocates for decentralised, user-owned data, challenging companies to envision a future where they no longer store sensitive personal data themselves.
Another significant challenge lies in implementing this system technically, as Schluss aims to avoid central servers that could expose user information to tracking. Instead, the architecture must allow vaults to open independently, without any centralised components monitoring that activity. Additionally, while companies often rely on stored copies of data that become outdated over time, the Schluss vault offers real-time accuracy. By drawing data directly from a person’s vault, organisations can be assured of its authenticity, especially since this data comes with verification from its source. This model improves data reliability and aligns with privacy regulations, allowing organisations to comply with stricter standards, such as GDPR, without the ongoing costs and risks of maintaining extensive data storage.
The Vault
Designing a vault meant to give individuals full control over their personal data calls for a secure and layered system. Schluss explained it should separate the data storage, identification, and authorisation. These three layers form a protective structure to maintain privacy and autonomy. “We have to build it in such a way that your sovereignty is guaranteed, also from a technical perspective.” The system is built to avoid these layers being merged. “We see in the big platforms that some of these layers are combined, which gives them power over you.”. Instead of a centralised storage solution, the Schluss vault is a system where data resides solely in each user’s vault, while identity and authorisation checks remain separate. All components, developed through open-source technologies, are built to ensure that only the individual can authorise data access and disclosure, and no central authority can monitor vault activity. “That is the core and only functionality of your vault.”
From the user’s perspective, the Schluss vault functions similarly to a banking app. Users can view their data, track who has requested it, and manage disclosures. In Europe, where data wallets are under discussion, Schluss envisions the vault as the core layer that data wallets will operate on—keeping personal data and service access strictly separated. Users can upload documents like photos, diplomas, and health records, while governments, banks, or other entities add verified credentials, all stamped with a unique digital mark. These marks can be verified without revealing the data itself, protecting the user’s privacy. If two people both have a Schluss vault, they can securely exchange specific data points. The ultimate goal, as Schluss envisions, is for each vault to be co-owned in a cooperative model, ensuring that users—not corporations or governments—have ownership over their digital identity.
Advancing Data Sovereignty
The partnership between Schluss and ALTEN is pivotal in advancing Schluss’s vision of data sovereignty. Schluss initially tried and tested a beta version of their vault and decided to revamp the platform entirely to improve it. ALTEN joined at this stage, bringing both development expertise and technical frameworks to support the rebuild. The decision was made to switch from iOS to the .NET MAUI framework, enabling a single code base. This choice is aligned with ALTEN’s experience and technical capacity. With this framework, ALTEN’s Idle Space developers and testers worked collaboratively on the renewal of the vault.
With ALTEN’s contributions, the team includes architects, developers, cybersecurity experts, and advisors, all aligned with Schluss’s mission. Schluss hopes that the collaboration will be further strengthened by external support through research organisations researching the topic. Despite challenges with funding, the project continues to evolve, focusing as much on storytelling and advocacy for data sovereignty as on technical innovation.
Future Steps
Looking ahead, Schluss is transitioning from the perception that they are a technical developer making a wallet or a vault, to “an organisation that is clearly striving for a mission”. Strategically, they are aiming to unite at least ten diverse organisations from different sectors to advocate for the mission and their vault. By partnering with various actors, Schluss hopes to demonstrate the value of individual data control and clarify the benefits for corporations as well as for users. The way to bring it to the market could very well be through these organisations. So, their approach involves three pathways: engaging governments and the EU, developing the vault through industry collaboration, and investing in research to refine the technical roadmap.
ALTEN’s collaboration with Schluss is evolving as we work to streamline the development process. Initially, we faced challenges with team continuity, as developers rotated in and out of the project, making it difficult to maintain focus. Schluss learned that new team members needed more consistent guidance and a clearer introduction to the project. Going forward, they plan to structure this by providing a solid onboarding process, ensuring newcomers understand the context and objectives of the Schluss mission. Developers will also have the option to focus either on the app rebuild or specific research areas, allowing for more manageable tasks and the freedom to use our knowledge. In addition, Schluss is focusing on using this knowledge and ensuring that work is easily transferable as the ALTEN team members move on to another project. The goal is to get back to building proof of concepts quickly and efficiently, with fresh ALTEN talent joining the team to help Schluss move forward with its mission.
Take a look at ALTEN’s testimonials
Bob van Hout
Within this project, there’s a collaborative space for both front-end and back-end engineers which is ideal to gain first experience with clients. As Project Leader, I’ve guided the team in developing a prototype that embodies the Schluss vision. Schluss gives me the opportunity and freedom to contribute to their vision by using our chosen framework: .NET MAUI combined with Blazor. .NET MAUI enables me to develop a multi-platform app with a single codebase. Blazor enhances this by providing access to the native APIs of the device the app runs on. What I find particularly exciting about combining .NET MAUI with Blazor is that it allows me to build a robust application for all possible platforms with limited knowledge of different programming languages and frameworks.
Lisa Brand
The Schluss project is about taking back ownership of your data. Within ALTEN we have a team of software developers and testers working on the project in a Scrum way and we are in regular and close contact with our stakeholder. As a tester, I’ve applied insights from ALTEN’s software testing masterclass while leveraging my background in Industrial Design and Human-Technology Interaction. I brought my expertise in user experience design, interpreting the results of usability research, and customer journey mapping to the table. We define requirements, create user stories, and document processes to support Schluss’s .NET MAUI and Blazor prototype. Currently, our test team is setting up an Appium-based automation test framework. With a continuously changing team, we get to get the best out of each other and create impact together with Schluss.
