Help Center/ Data Security Center/ User Guide/ Data Security Operations/ Watermarks
Updated on 2026-08-19 GMT+08:00
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Watermarks

Enterprises distribute various service files embedded with watermarks. Once data leakage occurs, it is difficult to extract watermarks for source tracing due to file type, permission, and specification restrictions. Huawei Cloud DSC watermark source tracing helps you parse watermarks of databases, OBS, and local files, quickly locate leakage sources, and support security event handling and compliance proof.

This section lists the unified entry to the watermark source tracing function. To extract watermarks from documents, images, and databases, choose Security Management > Data Watermarking. For details, see Data Watermarking.

Concepts

Table 1 Basic concepts

Concept

Description

Watermark

Watermark source tracing is the inverse operation of watermark embedding. Watermark source tracing extracts the invisible watermarks embedded in leaked files to trace the data transfer subject, locate the leakage source, and determine the responsibility.

Visible watermark

A visible watermark can be viewed directly on the image, helping to identify the person responsible for the leak.

Invisible watermark

The content of an invisible watermark remains unseen until it is retrieved through a specialized watermark extraction tool. The DSC console facilitates this process by offering a watermark extraction feature for images. Detailed instructions on how to extract watermarks from files stored in OBS buckets or from local files are provided in this section.

Prerequisites

Watermarks have been embedded to the source file for watermark source tracing. For details about how to embed watermarks, see Data Watermarking.

Constraints

Type

Constraints

Extracting Watermarks from a Database
  • The source file must be in CSV format and cannot be larger than 20 MB.
  • The table may contain more than 1,500 rows of data.
  • The CSV file content is encoded in UTF-8 mode. Ensure that the data is complete and correct.

Extracting Watermarks from an OBS Bucket Document
  • OBS asset access permissions are granted. For details, see Allowing or Disallowing Access to Cloud Assets.
  • OBS is enabled and in use.
  • The file format is PDF, PPT, Word, or Excel.
  • This section describes how to extract invisible watermarks from PDF, PPT, Word, or Excel documents.
  • The file size cannot exceed 20 MB.

Extracting Watermarks from a Local Document
  • OBS asset access permissions are granted. For details, see Allowing or Disallowing Access to Cloud Assets.
  • OBS has been enabled and used.
  • The document format is PDF, PPT, Word, or Excel.
  • This section describes how to extract invisible watermarks from PDF, PPT, Word, or Excel documents.
  • The file size cannot exceed 20 MB.

Watermark Source Tracing

Watermark source tracing is available for databases, OBS bucket documents, and local documents.

  1. Log in to the DSC console.
  2. Click in the upper left corner and select a region or project.
  3. In the navigation pane on the left, choose Data Security Operations > Watermark Tracing. The Database Watermark Extraction tab is displayed.
  4. Click Create Task. In the displayed dialog box, set parameters based on Table 2.

    Table 2 Creating a watermark extraction task

    Parameter

    Description

    Task Name

    Enter a task name.

    Source File

    The source file must be in CSV format and cannot be larger than 20 MB. The table may contain more than 1,500 rows of data. The CSV file content is encoded in UTF-8 mode. Ensure that the data is complete and correct.

    Extraction Mode

    Select a watermark extraction mode from the drop-down list. For lossy column embedding and lossless column embedding, select Extract by Column. For lossless row embedding, select Extract by Row.

    Terms:
    • Lossy column embedding: Watermarks are directly added to column data, which may cause data modification or damage.
    • Lossless column embedding: When embedding watermarks, a pseudo column is generated that correlates with other attributes of the relational table, making it less detectable by attackers. Watermarks are then embedded into this pseudo column, thereby minimizing damage to the original data.
    • Lossless row embedding: When embedding watermarks, multiple pseudo rows are generated based on the constraints of various data attributes, such as the data type, data format, and value range. Watermarks are then embedded into the pseudo rows to reduce the damage to the original data.

    Delimiter

    Delimiters in a file. For example: comma (,)

  5. Click OK. The watermark extraction task is created.
  6. Locate a task and click View Result in the Operation column.

    Watermark extraction tasks that are being executed cannot be deleted. The deletion operation cannot be undone.

  1. Log in to the DSC console.
  2. Click in the upper left corner and select a region or project.
  3. In the navigation pane on the left, choose Data Security Operations > Watermark Tracing. The Database Watermark Extraction tab is displayed.
  4. Click the OBS File Watermark Extraction tab.
  5. Click Create Task in the upper left corner. The Create Task page is displayed.
  6. Set Task Name.
  7. Click Upload File and select the file whose watermarks you want to extract. You can select multiple OBS bucket files.

    Only PDF, PPTX, DOCX, and XLSX files that are no larger than 20 MB are supported.

  8. Click OK. The watermark extraction task is created.
  9. Click the target task name. In the dialog box that is displayed, view the watermark extraction task status and the invisible watermark content of the OBS bucket file.

    • Running: You can view the progress of the watermark extraction task.
    • Completed: The watermark content is displayed in the Invisible Watermarks column. If there are no invisible watermarks, -- is displayed.
    • Failed: The watermark extraction task fails to be executed. You can move the cursor to to view the failure cause.

  1. Log in to the DSC console.
  2. Click in the upper left corner and select a region or project.
  3. In the navigation pane on the left, choose Data Security Operations > Watermark Tracing. The Database Watermark Extraction tab is displayed.
  4. Click the Local File Watermark Extraction tab.
  5. Click Upload File to upload the local file from which you want to extract invisible watermarks.

    Watermark extraction is supported only for PDF, PPT, Word, and Excel files that are no larger than 20 MB.

  6. After the file is uploaded, click OK. The invisible watermark content is displayed in the dialog box.

References

Parent Topic: Data Security Operations