Page 48 - U4SSC Blockchain for smart sustainable cities

Case 3. Digital democracy and data commons, Barcelona

The Digital Democracy and Data Commons The user can choose to share anonymized
(DDDC) project is another pilot implementation data such as the age range or neighborhood
of the DEcentralised Citizens Owned Data of residence. The user signs the petition with
Ecosystem (DECODE) tools and governance a secured Yes or No vote. Any attributes to be
models for managing personal data (described shared are cryptographically combined with
in the Claim verification 18+). DDDC, based in a unique identifier related to the petition and
Barcelona, sought to test out the process of submitted to a blockchain ledger as a transaction.
integrating the DECODE tools into the DEcidim The DDDC system then has real-time data about
system, an existing participatory democracy how many votes have been cast that cannot be
platform. DEcidim was created by the city of associated with the voter. The cryptographic
Barcelona and is currently used by 60 000 people. validations ensure that only verified residents
It has also been implemented in dozens of cities have voted and that each vote is valid. DEcidim
near Barcelona and beyond the Spanish borders. deals only with the results of the petition which
DEcidim had a recurring issue. On the one are decrypted when each petition is closed.
hand, it needed to accept and count votes on Aggregated, anonymized results are made
petitions anonymously such that there is no way available via the Barcelona Now dashboard
to connect individuals with the votes they cast. (BCNNow) which uses data from DEcidim and
On the other hand, it needed to ensure that the the blockchain ledger. The blockchain ledger
people voting were eligible to vote such that effectively becomes a permanent and tamper-
results can be legally binding. It was also essential proof data common with anonymized datasets
to secure the confidence of users. Knowing that could be used to detect city problems.
the demographics of users would also assist in The system makes use of DECODE’s Zenroom,
mapping city problems and understanding who privacy enhancing technologies (PETs), the
uses the system. Chainspace distributed ledger, and the Coconut
The DECODE tools provide a way around this attribute-based credential scheme. The DECODE
problem by separating the verification of the Wallet functions allow users to consciously
voter from the process of casting and recording choose whether or not to share elements of
a vote. DECODE tools were combined with their personal data for analysis. Not even the
DEcidim to create the DDDC system. administrators of the system have any access to
information about user identities or how they
The new DDDC system provides a website that
verified participants can use to identify petitions voted.
that are of interest to them. The user is verified This pilot has shown that the DECODE technology
by an external credential issuer who checks can support that of DEcidim and their vision of
their credentials and loads a signed verified ID participatory democracy. The data commons
attribute into an app on their mobile device. element has included debates and workshops
These data are not shared with DDDC. Each around data policies and the potential uses of a
petition includes an overview of the issue and data commons for public good. This supports the
(optionally) a request for personal data. goals of the DECODE project to advance citizen-
centric data governance and a more democratic
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