File Watermarks

Constraints

• Invisible watermarks can be inserted into and extracted from structured data files that are no longer than 4 MB.
• Visible watermarks can be inserted into unstructured data files that are no longer than 20 MB.
• Watermarks cannot be injected into files that already contain watermarks.
• The data in structured data files into which watermarks are to be inserted must meet the following requirements:
  • The source data must contain 5,000 or more lines. If the source data contains less than 5,000 lines, watermarks may fail to be extracted due to insufficient features.
  • You are advised to select a column with various data values. If all the values of the column can be enumerated, the extraction may fail due to insufficient features. Common columns that can be embedded with watermarks include the address, name, UUID, amount, and total amount.
  • If a watermark is inserted into a numeric integer field, the data may be modified. Insert watermarks into a field whose value can be changed.
• Watermark extraction from structured data files is irrelevant to the source tracing tasks using data watermarks. Only users under the same account can extract watermarks from structured data files into which watermarks have been inserted by following the instructions in Inserting a Watermark or Dynamic Watermarks.
• For details about the constraints on file watermarks, see File Watermark Constraints.

Inserting a Watermark

1. Log in to the DataArts Studio console.

   For details, see Accessing the DataArts Studio Instance Console.

2. On the DataArts Studio console, locate a workspace and click DataArts Security.
3. In the navigation pane on the left, choose Privacy Protection File Watermarks.
   Figure 1 Accessing the File Watermarks page
   

4. Set the parameters listed in Table 1.

   Table 1 Parameters for inserting a watermark

   Parameter	Description
   *Data Type	Select a file type. Structured data: CSV, XML, and JSON. You can insert an invisible watermark into a file and extract the watermark. Unstructured data: DOCX, PPTX, XLSX, and PDF You can insert a visible watermark into a file and open the file to view the watermark.
   Structured data
   *Watermark Content	Watermark ID that will be embedded by the system into data tables. The watermark ID can contain a maximum of 16 characters.
   *Data	CSV, XML, or JSON files are supported.
   *Field	Fields into which the watermark is to be inserted. Note that the data type of a field is determined by the data in the first line. You can also change the data type. You are advised to set the data type to string and insert watermarks.
   Unstructured data
   *Watermark Content	Watermark ID that will be embedded by the system into data tables. The watermark ID can contain a maximum of 16 characters.
   Transparency	Transparency of the plaintext watermark
   Rotation Angle	Rotation angle of the plaintext watermark
   Font Size	Font size of the plaintext watermark
   *Data	DOCX, PPTX, XLSX, and PDF files are supported.

5. Click Insert Watermark. The browser automatically downloads the inserted file.

   You can click Reset to restore the parameters to default settings.

Extracting a Watermark

You can extract invisible watermarks that have been inserted into structured data files in CSV, XML, or JSON format. For details about watermark insertion, see Inserting a Watermark.

1. Log in to the DataArts Studio console.

   For details, see Accessing the DataArts Studio Instance Console.

2. On the DataArts Studio console, locate a workspace and click DataArts Security.
3. In the left navigation pane, choose File Watermarks. In the right pane, click the Watermark Extraction tab.
   Figure 2 Accessing the Watermark Extraction page
   

4. Set the parameters listed in Table 2.

   Table 2 Parameters for extracting a watermark

   Parameter	Description
   *Data Type	File type. Only CSV, XML, and JSON are supported. You can insert an invisible watermark into a file of any preceding type and extract the watermark.
   *Watermark Content	You do not need to set this parameter. The extracted watermark will be automatically displayed.
   *Data	Select the structured data file in CSV, XML, or JSON format into which an invisible watermark has been inserted based on Inserting a Watermark.

5. Click Extract Watermark. The extracted watermark is displayed in the Watermark Content parameter.

   You can click Reset to restore the parameters to default settings.

File Watermark Constraints

• Structured data files

  Table 3 Constraints on invisible watermarks in data files

  Constraint Dimension	CSV (.csv)	JSON (.json)	XML (.xml)
  File size	≤ 4 MB	≤ 4 MB	≤ 4 MB
  File format verification	Suffix verification	Suffix verification	Suffix verification
  Minimum number of data rows	≥ 5,000 rows (recommended)	≥ 5,000 rows (recommended)	≥ 5,000 rows (recommended)
  Column type	STRING/INT/LONG/DOUBLE	STRING/INT/LONG/DOUBLE	STRING/INT/LONG/DOUBLE
  Column value diversity	Diversity required	Diversity required	Diversity required
  Watermark length	≤ 16 bytes (UTF-8)	≤ 16 bytes (UTF-8)	≤ 16 bytes (UTF-8)
  Watermark character	Letters, digits, hyphens (-), and underscores (_)	Letters, digits, hyphens (-), and underscores (_)	Letters, digits, hyphens (-), and underscores (_)
  CSV injection review	Output data check	N/A	N/A
  Concurrency	One watermark per domain	One watermark per domain	One watermark per domain
  Repeated injection	Not supported	Not supported	Not supported

• Unstructured data files

  Table 4 Constraints on visible watermarks in files

  Constraint Dimension	PDF (.pdf)	Word (.docx)	Excel (.xlsx)	PPT (.pptx)
  File size	≤ 20 MB (document annotation)	≤ 20 MB (document annotation)	≤ 20 MB (document annotation)	≤ 20 MB (document annotation)
  File format verification	The file must be in PDF format.	The file must be in OOXML format.	The file must be in OOXML format.	The file must be in OOXML format.
  File encryption	Possible failure	Not supported	Not supported	Not supported
  Number of sheets	N/A	N/A	≤ 3	N/A
  Number of rows	N/A	N/A	≤ 100,000 rows/sheet	N/A
  Number of columns	N/A	N/A	≤ 100 columns/sheet	N/A
  Watermark length	≤ 20 characters	≤ 20 characters	≤ 20 characters	≤ 20 characters
  Watermark content	Letters, digits, hyphens (-), and underscores (_)	Letters, digits, hyphens (-), and underscores (_)	Letters, digits, hyphens (-), and underscores (_)	Letters, digits, hyphens (-), and underscores (_)
  Concurrency	One watermark per domain	One watermark per domain	One watermark per domain	One watermark per domain