Digital Watermarking for Data Leakage Traceability: Techniques, Applications, and Challenges

With China's digital economy reaching $5.4 trillion and projected to become the world's largest data circle by 2025, data leakage has emerged as a critical security challenge, exemplified by 2020's 3.6 billion leaked records.

The presentation outlines four main topics: the current state of data leaks, digital watermark technology, its application in e‑commerce, and open research questions.

Digital watermarks are imperceptible signals embedded in host data to enable provenance tracking and copyright protection. A typical framework consists of a watermark embedding phase—where the original data and an encrypted watermark are combined—and an extraction phase—where the watermark is recovered to identify the source.

Evaluation metrics include imperceptibility, capacity, robustness, practicality, and security. Various watermarking methods are discussed: image watermarks (LSB, DWT/DCT), text watermarks (layout changes, zero‑width characters, natural‑language substitution), and database watermarks (reversible schemes for numeric and character fields).

In e‑commerce, watermarks can protect sensitive user and transaction data across scenarios such as screenshot capture, bulk export, printed documents, and unstructured media. Solutions combine visible cues (e.g., user ID, timestamps) with invisible (dark) watermarks to enable traceability even after attacks like compression or cropping.

Practical challenges include the ease of removing visible watermarks, AI‑driven removal of image/video watermarks, handling ultra‑short texts (e.g., phone numbers), and optimizing computational and storage overhead.

Proposed mitigation strategies involve hybrid front‑end watermarks (visible + invisible), robust text watermarking for short fields, and comprehensive database watermarking that embeds identifiers in all tuples and leverages error‑correcting codes for tamper detection.

The talk concludes with open problems—such as designing universally hard‑to‑remove watermarks, protecting ultra‑short sensitive strings, and improving algorithm efficiency—highlighting that effective data‑leakage tracing requires a combination of watermarking, logging, and broader security measures.