Surrogate Generation System

The surrogate generation system replaces privacy-sensitive information with synthetically generated surrogates (e.g., a person originally named 'Irene Adler' is renamed to 'Buffy Summers'. For further information see our paper.

Usage

To use the surrogate generation system first edit the parameters in param.conf. Then run the system with:

python3 main.py

Requirements:

• The system was tested on Python 3.5, 3.6 and 3.8.
• For processing DATEs python-dateutil has to be installed.
• For language-specific requirements see the documentation under the language module.

Entities

The following privacy-sensitive categories are currently provided:

• FEMALE (female given names)
• MALE (male given names)
• FAMILY (family names)
• ORG (organization names)
• USER (user names)
• DATE (dates)
• STREET (street names)
• STREETNO (street number)
• CITY (names of cities, towns, villages or regions)
• ZIP (Zip codes)
• PASS (passwords)
• UFID (IDs, IPs, IBANs ...)
• EMAIL (email addresses)
• URL (URLs)
• PHONE (phone and fax numbers)

Note: The binary approach to first names does not reflect the non-binary gender identities individuals may identify with.

Input Format

The surrogate generation system accepts any type of text with BRAT annotations of the described entities. For each file to process the actual text without modifications ('.txt') and the annotations of the privacy-sensitive entities ('.ann') have to be provided separately. An example of the annotation format (the numbers denote the character offsets of the entities in the txt file):

T1	FEMALE 6 11	Irene
T2	CITY 126 132	London
...

For more information see the brat standoff format. Note: We don't handle discontinuous text-bound annotations yet.

Language Modules

To adapt the surrogate generation system to a specific language a language module has to be provided that handles the language-dependent categories (FEMALE, MALE, FAMILY, ORG, STREET, CITY, DATE).

German Language Module

We implemented a German language module (lang/de).

Requirements:

• spacy with the German model 'de_core_news_sm' (How to install)
• Levenshtein

The (large) substitute lists are stored in this repository with GIT LFS. Please install it for proper usage of these lists. To reduce the risk of re-identification, we recommend (slightly) modifying the substitute lists and the distributional letter-to-letter mappings.

Sources for Substitute Lists

• female.json, male.json, female_nick.json, male_nick.json
  • Jörg Michael: ftp://ftp.heise.de/pub/ct/listings/0717-182.zip (GNU Lesser General Public License (LGPL))
• family.json
  • Deutscher Familienatlas (DFA): http://www.namenforschung.net/fileadmin/user_upload/dfa/Inhaltsverzeichnisse_etc/Index_Band_I-V_Gesamt_Stand_September_2016.pdf
• org.json
  • OpenStreetMap contributors: https://www.datendieter.de/item/Liste_von_deutschen_Firmennamen_.txt (Open Data Commons Open Database License (ODbL))
• street.json
  • OpenStreetMap contributors: https://www.datendieter.de/item/Liste_von_deutschen_Strassennamen_.csv (Open Data Commons Open Database License (ODbL))
• city_rec.json, city.json
  • GeoNames: http://download.geonames.org/export/dump/ (Creative Commons Attribution 4.0 License)
  • Statistik Austria — data.statistik.gv.at: https://www.statistik.at/strasse/suchmaske.jsp (Creative Commons Attribution 4.0 License)
  • OpenGeoDB: http://www.fa-technik.adfc.de/code/opengeodb/PLZ.tab
  • Amtliche Vermessung Schweiz / swisstopo: https://www.cadastre.ch/de/services/service/registry/plz.html

Requirements for Implementing a Language Module

To build a language module follow the structure of the German language module in the lang/de package. All the requirements have to be properties of the specific language object (see class 'German').

Substitute Lists

Appropriate substitutes for the categories FEMALE, MALE, FAMILY, STREET, CITY and ORG are required. They have to be provided as dictionaries where the key is the first letter and the values are lists with names starting with this first letter and named after their category (see lang/de/init.py).

Date Formats

You also have to provide your own date formats as done in the file lang/de/dateFormats.py.

(Distributional Letter-to-Letter Mappings)

Optionally you can define first-letter mappings depending on their frequency (see lang/de/freqMaps.py). Otherwise the mappings will be inherited from the file lang/langDefaults.py, which are frequency independent.

(Extensional Functions)

Functions for a different treatment of a specific language-dependent category will also be the default ones (replacing each entity with the unchanged entry of the substitute list) if you do not overwrite them in your own language module as shown in the German class in lang/de/init.py.

Citation

If you use or extend the surrogate generation system please cite:

@inproceedings {Eder19,
	author = {Eder, Elisabeth and Krieg-Holz, Ulrike and Hahn, Udo},
	title = {De-identification of emails: pseudonymizing privacy-sensitive data in a German email corpus},
	booktitle = {Proceedings of the International Conference Recent Advances in Natural Language Processing, RANLP 2019. Varna, Bulgaria, 2-4 September, 2019},
	year = {2019},
	publisher = {Incoma Ltd.},
	pages = {259--269},
	editor = {Angelova, Galia and Mitkov, Ruslan and Nikolova, Ivelina and Temnikova, Irina},
    url = {https://www.aclweb.org/anthology/R19-1030},
    doi = {10.26615/978-954-452-056-4_030},
}