red_mad_robot

PII-Guard: Open-Source Detector for Personal Data in Russian Text

Andrey Ivanov, an NLP researcher at red_mad_robot, has released PII-Guard, an open-source system that detects and masks personal data in Russian text before it reaches language models. The tool combines rule-based checks with a fine-tuned ruBert-base NER model to handle names, addresses, phones, passports, INN, SNILS, bank cards and other entities. It replaces detected PII with structured XML-like tags that preserve grammatical information such as gender and entity ID, allowing models to generate coherent responses that are later restored with real values. The hybrid pipeline first applies normalization, pattern matching, Luhn and weighted checksum validation, and context windows with positive and negative keywords, then merges results with model predictions via an arbitration module. Evaluation on four public datasets, including Hivetrace, alexen2 and alrosait, shows PII-Guard outperforming other open solutions on both strict span matching and type-overlap micro-F1 metrics. The project, including datasets and code, is available on GitHub and aims to reduce leakage risks while maintaining downstream model utility.