Blockchain on the Move – Giving you control of your own digital identity

City of Antwerp
City of Antwerp/Digipolis Antwerp
BLING Final Book article
Reading Level
Readiness criterium
Blockchain architecture, Data handling, Legal Requirements, Mandate


Blockchain on the Move is a Self Sovereign Identity (SSI) proof of concept between the City of Antwerp, VICTOR, and Information Flanders that aimed to develop tools and approaches to give citizens control over their own data, and to link this with Antwerp’s A-card to give better access to services.

A Self Sovereign Identity proof of concept between the city of Antwerp, VICTOR, and Information Flanders

Joris Moorthamers and Kris van Berendoncks – Stad Antwerpen, Belgium

Is blockchain part of the solution to a number of tricky issues around identity, privacy, and online transactions? And if it is part of the solution, what’s the best way to make it part of the solution? The City of Antwerp explored this question – in co-creation with Digipolis, Information Flanders, and the Flemish ICT organisation (V-ICT-OR) – in the ‘Blockchain on the Move’ project. The project’s goal was to develop an approach that would give citizens control of their data by giving them a digital identity – on blockchain.

Blockchain on the Move aimed to develop tools and approaches to give citizens control over their own data. In a digital world the protection and management of personal data is becoming increasingly important – and if you are in control of your own personal data, you can decide for yourself how, when, with who, and for how long you share this information.

Using Self Sovereign Identity to manage information

Information about citizens is often stored in multiple databases which are managed by a wide range of different organizations. Citizens are often unable to manage this data, don’t understand how and where this data is being used, and usually can’t make sure that it is accurate or complete. The project partners wanted to develop innovative solutions that would safely and transparently handle data and transactions between citizens and the government.

With a self-managed identity (Self-Sovereign Identity or SSI that can be provided throughblockchain-enabled systems, Blockchain on the Move aimed to provide a recognised process to enable citizens to take ownership of both their own data and their digital identity.
By using SSI approaches to manage theirdata, citizens can both validate their own
data – ensuring that names and addresses are correct for example – and then easily share this validated data if they wish to. SSI approaches should also allow citizens to understand and manage which organisations are able to see and use any data that the citizen chooses to share.

SSI and blockchain

Blockchain technology stores data in a decentralized way. With SSI, the individual is
in control of their own data and can decide who to share their data with – and the user can also withdraw the right to use their data. Rather than having personal information in many central databases, SSI enables the user to control their own data in one place, and to then decide which third parties are allowed to have limited access to it. SSI solutions remove the need for intermediary or third-party agencies (e.g. Google or Facebook) to provide identify services for users. As permissions to access data is controlled by access to the blockchain, SSI solutions also mean that only those who are given the correct key can open the ‘lock’ and consult or use certain data that is managed through the blockchain. Blockchain solutions also offer cryptographic mechanisms to confirm that their information has not
been accidentally or intentionally modified. Blockchain on the Move (BotM) was the
first attempt by project partners to provide Antwerp’s citizens with a Self-Sovereign Identity (managed through a blockchain solution) that they could use with governments, public organisations, or companies.

The project also looked at developing a ‘digital vault for citizens’. Citizens would be able to manage and store their own data in the vault, and grant access to this data to third parties. The initial use case for this tool would be for the ‘relocation process’ – citizens would use their digital vault to share information with the city to streamline the registration of a household move. This seemingly simple process actually triggers a complex set of processes in the city, and the partners were looking for ways to simplify and automate the processes.

The Blockchain on the Move plan

The initial Blockchain on the Move plan had two phases:

Phase 1

Development of the Self-Sovereign Identity (SSI)-building block – a generic ID solution based on Blockchain technology that could be used in service development and testing, and

Phase 2

Development of the ‘relocation process’ use case.

At the end of Phase 1 Jolocom GmbH delivered a proof of concept (POC) or ‘first version’ of the SSI building block. This illustrated the potential of SSI, but was not the ‘total’ SSI building block the partners had envisaged.

The BotM partners then revised plans for Phase 2, and used the SSI proof of concept built in Phase 1 to examine the potential feasibility and added value of SSI-based optimisation of some of the processes used by the City of Antwerp. This envisaged using a central customer

profile – based on the citizen’s self-managed identity – to improve and simplify service delivery and management.

BoTM Use Case 1: linking the A-card and the A-profile

The A-card is Antwerp’s user card, which gives citizens and visitors access to many

of the city’s services, including libraries, swimming pools, youth and district services, and household waste disposal facilities.

The card plays three different roles in the city:

  • it is a loyalty and access card for leisure service users – for both city and private leisure services
  • it is a user pass that grants access to various city services, and
  • it is a personal discount card for residents receiving financial support or on low-incomes

You can apply for an A card at more than 100 locations in Antwerp: at the city shop, at museums, at libraries and pools, at one of the city’s service counters, and so on. More than 750 city employees are trained to deliver this service.

After registration, a unique A-card number can be linked to the citizen. If you receive certain kinds of government support this can also be linked to your A-card.

When the proof of concept was being developed, administrative simplification was a key aim: the rules about services and service access that are delivered through the A-card (e.g. the costs of services, reward criteria for frequent service users) are made in 8 different parts of the organisation. There is also a need to understand how services are being used across the city – which was not particularly straightforward with the information they were collecting through the A-card at the time.

The A-profile concept

Using an A-profile, a citizen can log on to various websites of the city of Antwerp and receive customised information and support. The ‘A-profile’ would be used when the citizen accessed the city’s digital services, such as making requests or requesting documents via the e-desk. Information linked to the citizen’s account would be used when applying for or managing service use, so the user would not have to repeatedly provide the same information to the city.

The partners used a series of brainstorming sessions and workshops with city employees to map and structured the end-to-end (E2E) track for the A-map and the link with the A-profile. The process moves through successive phases: applying for an A card, the possible linking of the A card to the A profile, the use of the A card, changing the data relating to the A card and reporting on the use of the A card towards management and the service providers.