Pseudonymisation
Pseudonymisation is the process of replacing personal data with fictional identifiers (pseudonyms), such as unique codes or numbers, while preserving the possibility of reconstructing the original information if necessary to achieve the objectives of the research. This process can be carried out manually or with the help of IT tools.
Choice of pseudonymisation strategy
Pseudonymisation can be implemented using different methods. Depending on the type of data and the objectives of the research, the most appropriate strategy should be chosen.
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Key table: key file; lookup table; coding table) |
Hash function |
Encryption (English: encryption) |
| Manually entered |
✔ |
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| Technically simple |
✔ |
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| Pseudonymisation is based on an algorithm |
|
✔ |
✔ |
| Suitable for large volumes of data |
|
✔ |
✔ |
| Feedback |
✔ |
|
✔ |
| Control over the choice of pseudonym |
✔ |
|
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| Higher risk of re-identification |
✔ |
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Both key tables and algorithmically generated aliases are valuable tools for data protection. Key tables offer simplicity and direct control, but can be difficult to use for large amounts of data. Algorithmic aliases offer efficiency and consistency over large data sets, but can be more technically complex and, if not implemented correctly, can reveal patterns that can facilitate identity recovery (de-anonymisation).
