Anonymising documents

Municipality of Wassenaar

Recognise and anonymise privacy-sensitive information and documents.

Last change on 31st of March 2026, at 13:15 (CET) | Publication Standard 1.0

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

General information

Theme

Organisation and business operations

Begin date

2023-01

Contact information

[e-mail]

Responsible use

Goal and impact

PURPOSE: The anonymisation software is used to give substance to transparency on the one hand and the necessary protection of the individuals and companies to whom documents relate on the other.

IMPACT: The impact of the algorithm on citizens and companies is low. The algorithm searches specifically for (personal) data and masks or deletes them regardless of the further content of the documents.

Considerations

Using anonymisation software simplifies disclosure.

Automated anonymisation is less error-prone than human intervention.

There is less chance of a data breach. Citizens' and companies' data are better protected.

Human intervention

The employee always has the option to modify the algorithm's suggestion.

Risk management

Risks are monitored broadly and discussed where necessary. In particular, we look at the likelihood of data being traceable anyway and potential data breaches. There are basic measures, such as monitoring operation and maintaining log files. We also pay attention to legal and ethical issues, such as inadvertent identification. If we see risks, we take appropriate measures and improve the way we work step by step.

Legal basis

Links to legal bases

• Disclosure Act: https://wetten.overheid.nl/BWBR0004287/2024-01-01
• Environmental Law (General Provisions) Act: https://wetten.overheid.nl/BWBR0024779/2023-04-19
• General Administrative Law Act: https://wetten.overheid.nl/BWBR0005537/2024-05-01
• Open Government Act: https://wetten.overheid.nl/BWBR0045754/2023-04-01
• Electronic Publications Act: https://wetten.overheid.nl/BWBR0043961/2024-01-01
• Municipal Act: https://wetten.overheid.nl/BWBR0005416/2024-01-31
• General Data Protection Regulation Implementation Act: https://wetten.overheid.nl/BWBR0040940/2021-07-01/0
• General data protection regulation: https://autoriteitpersoonsgegevens.nl/uploads/imported/verordening_2016_-_679_definitief.pdf

Operations

Data

Personal names, addresses, postal codes, telephone numbers, e-mail addresses, BSN, VAT numbers, IBAN account numbers, IDs, municipal employees, signatures, special personal data, license plates, face

Technical design

The algorithm recognises (personal) data and otherwise confidential information in a document and makes a proposal to anonymise it. An employee evaluates the proposal and makes the final adjustment so that the document is suitable for publication. The use of anonymisation software makes it faster and easier for the municipality to make documents suitable for publication. Automated anonymisation also appears to lead to fewer errors. This reduces the risk of a data leak and citizens' and companies' data are better protected. The outcomes are no different from if this work were done manually by humans.

External provider

Zylab