schift-ko-pii-v4

111M parameter Korean PII detector that outperforms models 3x its size.

Fine-tuned from klue/roberta-base with LoRA on Korean legal, financial, and administrative texts. Distributed as bf16 safetensors (210 MB).

Benchmark

Two benchmark suites are included in this repository under benchmark/.

benchmark_v1 (93 cases)

Same benchmark, same scoring (50% overlap match), no postprocessing on either side.

benchmark_v2 (253 cases)

Expanded benchmark with harder cases: investigation reports, complex address formats, foreign/Hanja names, mixed-entity documents.

With postprocessing enabled (postprocess=True):

Category breakdown (benchmark_v1, raw model)

LFM2.5 is a strong multilingual model, but it was not trained on Korean-specific formats: vehicle plates (52가1234), resident registration numbers (850205-1234567), Korean date expressions (2024년 3월 15일), or rare Korean surnames (황보, 남궁, 독고).

Quick start

pip install schift-ko-pii

from schift_ko_pii import detect, mask, apply

# Detect PII spans (each entity gets a sequential id)
spans = detect("피고 김민수의 전화번호는 010-1234-5678이다.")
# [
#   {"id": "person_1", "start": 3, "end": 6, "label": "private_person", ...},
#   {"id": "phone_1", "start": 14, "end": 27, "label": "phone_number", ...},
# ]

# Mask: get masked text + entity map in one call
result = mask("피의자 김철수가 피해자 박영희에게 서울시 강남구에서 금품을 전달하였다.")
print(result["masked"])
# 피의자 [사람1]가 피해자 [사람2]에게 [주소1]에서 금품을 전달하였다.

for e in result["entities"]:
    print(f"  {e['id']}: {e['text']}")
# person_1: 김철수
# person_2: 박영희
# address_1: 서울시 강남구

# Apply: replace selected entities (user can edit the map before applying)
text = apply(
    "피의자 김철수가 피해자 박영희에게 서울시 강남구에서 금품을 전달하였다.",
    result["entities"],
    replacements={"person_1": "OOO", "person_2": "△△△"}
    # address_1 omitted → left unmasked
)
# 피의자 OOO가 피해자 △△△에게 서울시 강남구에서 금품을 전달하였다.

# With postprocessing (regex validation + structured-ID rules)
spans = detect("주민번호 850205-1234567을 확인.", postprocess=True)

Postprocessing

The postprocess=True flag applies Korean-specific rules:

• Regex validation for structured IDs (resident numbers, passports, vehicle plates, bank accounts)
• Luhn/checksum verification where applicable
• Context-aware span merging
• False-positive suppression for legal case numbers and statute references

API (free)

For production use without managing model files:

from schift import Schift

client = Schift(api_key="...")  # free at schift.io
result = client.pii.redact("김민수의 전화번호는 010-1234-5678입니다.")
# Postprocessing is always enabled on the API.

Labels

Running benchmarks

# Benchmark this model (v1, 93 cases)
python benchmark/run_benchmark.py

# Benchmark v2 (253 cases)
python benchmark/run_benchmark.py --benchmark benchmark/benchmark_v2.jsonl

# With postprocess
python benchmark/run_benchmark.py --postprocess

# Compare any HuggingFace model
python benchmark/run_benchmark.py --hf-model LiquidAI/LFM2.5-Encoder-350M-PII-Detector

Model details

• Base model: klue/roberta-base (111M params)
• Training: LoRA adapter on ~20k Korean legal/financial/admin examples
• Format: safetensors bf16 (210 MB)
• Inference: transformers pipeline, CPU or GPU
• Max length: 512 tokens
• Tagging scheme: BIES (Begin/Inside/End/Single)

License

Schift License v2.0 — Apache 2.0 base with a revenue threshold. Free for everyone under $10M annual revenue. Research, education, and non-profit use always permitted. Companies above the threshold: contact hello@schift.io.

Citation

@software{schift_ko_pii_2026,
  author = {Schift Inc.},
  title = {schift-ko-pii: Korean PII Detection Model},
  year = {2026},
  url = {https://huggingface.co/schift-io/schift-ko-pii-v4},
}