Anonymisation tool Datamask

Municipality of Arnhem

The algorithm in the municipality of Arnhem's anonymisation tool recognises and anonymises, among other things, (personal) data and confidential data in documents before they are published or shared.

Last change on 30th of October 2024, at 11:29 (CET) | Publication Standard 1.0

• Publication category: Other algorithms
• Impact assessment: Field not filled in.
• Status: In use

General information

Theme

Organisation and business operations

Begin date

06-2024

Contact information

[e-mail]

Link to publication website

opendata.arnhem.nl

Responsible use

Goal and impact

The anonymisation tool is used to prevent personal or confidential data from being unintentionally shared or disclosed

Considerations

Anonymisation is an effective way to protect personal data and reduce the risks of processing it. An advantage of using this algorithm is that (personal) data can be anonymised more efficiently and effectively. That is, anonymisation happens faster and more accurately compared to a completely manual process.

Human intervention

An employee checks the result at all times and makes adjustments where necessary.

Risk management

The risk of this algorithm is minimal because an employee always checks the result.

Legal basis

General Data Protection Regulation (AVG):

Anonymisation is an effective way to protect personal data and reduce the risks of processing it. When data is properly anonymised, it no longer falls under the scope of the AVG as it is no longer traceable to a natural person. Therefore, anonymisation is often applied as a security measure to comply with the AVG principles. Although the AVG does not contain a specific article on anonymisation, recital 26 does refer to "the anonymisation of personal data" as a way to reduce risks to data subjects to an acceptable level. Anonymisation is thus seen as an important technique to effectively protect personal data in line with the AVG.

Open Government Act (WOO):

Under Article 5.1(2)(f) of the Woo, information does not have to be disclosed insofar as its importance does not outweigh the interest in respecting personal privacy. This means that if government information contains personal data, such data need not be disclosed due to the interest of privacy protection. Anonymising personal data is then a logical step to still be able to make this information (partially) public

Links to legal bases

• Algemene Verordening Gegevensbescherming (AVG): https://eur-lex.europa.eu/legal-content/NL/TXT/HTML/?uri=CELEX:32016R0679&qid=1685451198313
• Wet open overheid : https://wetten.overheid.nl/BWBR0045754/2023-04-01

Elaboration on impact assessments

The municipality of Arnhem conducted a DPIA on Datamask's Anonymisation Tool.

Operations

Data

This depends on the document being anonymised. Examples include personal data such as e-mail addresses, phone numbers, bank account numbers, address details and signatures. And based on the Open Government Act (Woo), it can also include data beyond personal data. These grounds for exception are listed in the Woo.

Technical design

The algorithm is trained to identify personal data. The employee enters a document so the process starts. The algorithm suggests (personal) data that should be anonymised. The employee manually reviews this to ensure that only necessary data is anonymised.

External provider

DataMask B.V.