statistical computing / systems / LLM watermarking

Xingchi Li

Google SWE. fastcpd, change points, watermark signals.

Scholar GitHub CV LinkedIn i.at.lixingchi.dot.com

fastcpd / change point detection

Breaks, surfaced.

the series streams in

streamdetectsegmentexplain

τ₁ = 376 τ₂ = 635 τ₃ = 812

0 0 1 0 1 0 0 0 1 1 0 0 0 1 0 0 1 0 1 0 0 1 1 0 1 0 1 1 0 1 1 1 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 1 11 0 1 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 1 0 0 0 0 0 1 1 1 0 0 1 1 0 0 0 1 1 1 0 0 1 1 1 0 0 0 0 0 1 0 1 1 0 0 0 1 0 1 1 1 0 1 1 10 0 0 0 0 0 1 1 1 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 0 1 0 0 1 1 1 0 1 0 0 0 1 1 1 0 0 1 11 1 0 0 0 1 1 1 1 1 0 1 0 0 0 1 1 0 0 0 0 1 0 0 0 0 1 1 0 1 1 1 0 0 0 0 1 0 1 1 1 0 0 0 0 0 0 0 1 0 0 0 1 0 0 1 1 1 0 0 0 1 1 10 1 1 0 0 1 0 1 1 0 1 1 1 0 0 1 0 0 1 1 1 1 0 1 0 1 0 1 0 1 1 1 0 0 1 1 0 1 1 0 0 1 0 1 1 0 0 1 0 1 0 1 1 0 1 1 1 1 1 0 0 1 1 00 0 1 0 0 1 0 0 1 1 1 1 1 0 1 1 0 1 1 1 0 0 0 1 0 1 0 0 1 1 1 0 0 1 1 1 1 0 0 0 1 0 1 0 0 1 0 1 0 1 1 1 1 0 0 0 0 1 0 1 0 0 1 11 0 1 0 1 0 0 0 1 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 0 1 1 0 1 0 1 0 1 1 0 1 0 1 0 0 0 0 0 1 1 0 1 0 0 0 1 1 1 0 1 1 0 0 0 0 1 1 1 10 0 1 1 0 0 0 1 1 0 1 1 1 0 1 0 1 1 1 0 0 1 0 1 0 1 0 1 0 1 1 0 1 1 0 1 0 1 1 1 0 1 1 1 1 0 1 1 1 1 0 0 1 0 1 0 1 0 0 0 1 0 0 01 0 1 0 0 0 1 0 1 1 1 0 1 0 1 0 1 0 1 1 1 1 0 0 0 1 0 0 0 0 1 1 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 0 10 1 0 1 0 0 0 0 0 1 0 0 0 0 1 1 0 1 0 0 0 1 1 1 0 0 1 1 1 1 0 0 1 0 0 1 1 0 1 0 0 1 0 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 0 1 1 1 0 00 0 1 0 1 0 1 1 1 0 0 0 0 1 1 0 1 1 0 0 1 0 1 0 1 0 0 1 0 0 0 1 0 0 1 0 0 1 1 1 1 1 0 0 1 0 1 0 0 1 0 0 0 0 1 0 1 1 0 0 1 1 1 00 1 0 1 0 0 1 0 0 1 1 1 1 1 1 0 1 0 1 0 1 1 0 1 0 0 0 1 0 0 1 0 0 0 1 1 1 1 1 0 0 0 0 1 0 1 1 1 0 0 0 1 0 0 0 1 1 0 1 1 0 1 1 01 1 0 1 0 1 0 1 0 0 1 0 0 1 0 0 0 1 0 1 0 0 1 1 1 0 0 1 1 0 1 0 0 1 0 0 0 1 0 0 0 1 0 1 0 0 1 1 1 0 1 1 1 1 1 0 1 1 0 0 0 1 0 10 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 1 1 1 1 0 1 1 1 1 0 0 0 1 0 0 1 0 0 1 1 1 0 1 0 0 0 1 0 1 0 0 1 1 0 1 0 1 1 1 1 0 1 1 1 0 0 10 1 0 0 1 0 1 1 1 1 0 0 0 0 0 0 1 0 0 0 1 1 1 1 0 1 1 0 0 0 1 1 0 1 1 1 1 0 0 0 1 0 1 1 0 0 0 1 0 1 1 1 1 1 0 1 1 0 1 0 1 1 1 00 0 0 0 1 1 0 1 0 0 0 0 1 0 1 0 0 0 1 0 1 0 1 0 0 0 0 1 0 0 1 1 0 0 1 0 0 1 1 1 1 0 0 0 1 1 0 1 0 0 0 0 1 0 0 1 0 0 1 1 0 1 1 01 1 0 0 1 1 1 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 1 1 0 1 0 1 1 0 1 1 1 1 0 1 0 0 1 0 1 0 0 0 1 0 0 1 0 0 1 1 0 1 0 1 1 1 1 1 10 1 0 0 1 0 0 1 0 0 0 1 1 0 0 0 1 0 0 1 0 0 0 0 0 1 0 1 0 0 0 0 1 1 0 0 1 1 0 0 0 1 0 0 1 1 0 1 0 0 1 1 0 0 0 0 0 0 0 1 0 1 0 11 0 1 1 0 0 0 1 0 0 1 1 1 1 1 0 1 1 0 0 0 1 1 0 1 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 0 1 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 1 0 0 0 00 0 1 1 1 0 0 1 0 1 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 1 1 0 1 1 1 1 1 1 1 0 0 1 1 1 1 1 0 11 0 1 1 1 0 1 1 0 0 0 0 0 0 0 1 0 0 1 0 1 0 0 1 1 1 1 1 0 0 0 1 1 0 0 0 0 1 0 1 1 0 0 0 1 0 1 1 1 1 1 0 1 0 0 1 0 0 0 0 0 0 1 11 0 0 0 0 0 1 0 0 0 0 1 0 1 0 1 0 1 0 0 1 1 1 0 0 1 1 0 0 1 1 1 1 1 0 0 1 1 1 0 1 0 0 0 1 1 0 1 0 0 1 0 0 1 1 1 0 0 1 1 0 0 0 01 1 0 0 1 0 0 1 1 0 1 0 1 1 0 1 1 1 0 1 1 1 0 1 1 0 0 1 0 1 0 1 1 0 0 0 1 0 1 0 1 0 1 0 0 0 1 0 1 0 0 0 1 0 0 0 0 0 0 0 0 1 0 11 1 0 1 0 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1 0 0 1 1 1 0 1 1 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 1 1 1 1 1 0 1 0 0 0 1 0 1 1 1 1 1 1 1 0 11 1 1 1 1 0 1 0 1 1 1 1 1 1 0 0 1 1 1 1 0 1 1 1 1 0 1 0 1 1 1 1 0 1 1 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 0 0 0 1 0 0 1 1 1 0 1 0 0 01 0 0 0 0 0 0 0 1 0 1 0 0 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 0 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 1 0 1 0 0 0 1 1 0 1 1 1 0 0 0 0 1 0 1 11 1 0 1 0 0 1 0 0 1 1 1 1 1 1 1 1 0 0 1 1 1 0 1 1 1 1 1 1 0 0 0 1 1 1 1 1 0 0 1 1 1 0 1 0 1 1 0 1 1 0 0 0 1 1 0 0 1 0 0 1 0 0 01 0 1 0 1 0 0 1 1 0 0 0 1 1 1 0 0 0 1 1 0 1 0 0 1 0 0 1 1 0 0 0 1 0 0 0 0 1 1 1 0 0 1 0 0 1 0 0 1 0 1 0 1 0 1 0 1 1 0 0 1 1 1 01 1 0 1 0 1 0 0 1 1 0 1 1 1 1 0 0 0 0 1 0 1 0 1 0 0 0 0 1 1 0 0 1 1 1 0 1 0 1 1 0 1 0 1 1 0 0 1 1 1 1 1 0 1 1 0 1 1 0 1 0 1 0 11 0 0 0 0 1 1 0 0 1 0 0 1 1 0 1 1 1 1 0 1 0 1 1 1 0 0 1 0 0 1 0 0 0 1 1 0 1 1 0 0 0 0 0 1 0 0 1 0 1 1 1 1 1 0 1 0 1 1 0 0 1 1 11 0 1 1 1 1 1 0 0 0 0 1 0 0 1 0 0 1 1 0 1 1 1 1 1 0 1 1 0 1 1 0 1 0 0 1 0 1 1 0 1 1 1 0 0 0 1 1 0 0 0 1 1 1 0 1 0 0 1 1 1 0 1 11 0 0 1 1 1 0 0 1 0 0 1 1 0 0 1 1 1 0 0 1 1 1 0 0 0 1 1 0 1 1 1 0 1 1 1 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 1 1 0 0 1 1 0 0 1 1 1 0 10 1 0 1 0 1 0 1 1 1 0 1 1 0 0 0 1 0 1 1 0 1 0 0 1 1 1 0 1 1 0 0 0 1 1 0 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 0 1 1 1 1 0 1 1 0 0 00 1 0 1 0 1 1 0 1 0 0 1 1 1 1 0 0 0 1 0 0 0 0 0 0 1 0 1 1 0 0 1 0 1 0 1 1 1 0 1 1 0 0 1 0 0 1 1 1 1 1 1 0 1 0 1 1 0 1 1 1 1 0 0

LLM watermarking

Publications

fastcpd: Fast Change Point Detection in R Journal of Statistical Software, 2026 A Likelihood Based Approach for Watermark Detection AISTATS 2025 Segmenting Watermarked Texts From Language Models NeurIPS 2024

Employment

Software Engineer Google LLC, July 2025 - present

Software Engineering Intern Google LLC, May - Aug 2023

Software Engineering Intern Google LLC, May - Aug 2022

Education

Ph.D. in Statistics Texas A&M University, 2020 - 2025

M.S. in Computer Science Georgia Institute of Technology, 2019 - 2020

M.S. in Mathematics Texas A&M University, 2018 - 2019

B.S. in Mathematics Beihang University, 2014 - 2018

Xingchi Li

Breaks, surfaced.

LLM watermark reveal

Publications

Employment

Education