Watermarking and Stamping Overview

Overview

Watermarking means different things to different people so we need to understand what we mean by a watermark first and then understand the concepts.

A watermark is a layer added to 1 or more pages of a PDF document to argument the information with contextual information from the host system. It is not possible to watermark the native document format e.g. Word, as these are both editable and come is such varied formats as it is not possible to consistently add information.

Below is a classic example of a watermark used in engineering in the additional of the current state of the document in the center of the page using a semi-opaque large text at a angle of 45 degrees.

file

Many types of industries use watermarking, but it is especially interesting to organizations under strict regulation - those in Areospace, Defence or Medical Applications.

What is a watermark?

A strict definition is the application of a semi opaque layer to all pages of a document. However, the technology to do this can be used to mark the document in many forms. For example, it can add the following features:

  • Text and images
  • Colors and textures
  • Footers and headers
  • Levels of opaqueness e.g. transparent or solid
  • Invisible text and codes
  • Page information
  • Add and remove pages

Any of the above information can contain or be logically controlled by meta data.

The information of the combination of the positioning of the above elements and the meta data are designed in a template.

file

Note: this design has a footer that is not opaque to add copyright information

This is designed with placeholders for the meta data but in addition can contain a logic engine to control the appearance of data based on business rules. An example of a rule may be

if ( state!=Released ) then show watermark splash mark

Following is an example of an excel document with a stamp applied. Not this has page numbering, state and footer information

file

Contextual meta data information

Contextual information clearly can add more information than purely the state, it can stamp the following information on the document:

  • Time and date of release
  • Approval date and user
  • Other team information
  • Copyright data
  • Change and business control object data
  • Logo and company identification
  • Time and date of download
  • Page totals and numbers
  • Page footers

Once this much more complex set of meta data is considered, it opens up a whole new scope of use:

  • Prevent incorrect usage
  • IP identification
  • Copyright information
  • Security marking
  • Compliance information

Coversheets and trailing pages

As a watermarking engine is appending data to existing pages, it can be programmed to add or remove pages from the document sets. As we increase the amount of meta data to add to a set, it becomes more reasonable to place this data on new sheets, which we have termed coversheets and trailing sheets. Both of them can be used to hold all the additional information, which is not stamped on each individual document without affecting the page number.

An example is as follows:

file

Watermarking for security

Clearly adding “ownership” data to the PDF helps to protect intellectual property (IP) however this can take two forms. One is a visible deterrent to IP theft, which can be removed using various and increasingly more sophisticated techniques. The other one is using the invisible watermark. We can add meta data to the document in the form of a code that can contain information that looks like any other technical information within the code of the PDF, but in fact contains meta data such as the user that downloaded the file, the IP of the machine and the time and date of download and other information of interest. This data can be decoded if an IP leak is discovered and the PDF in question has this “invisible” code.

Encryption

None of the above security techniques can ensure 100% guarantee, which is why in some cases the PDFs can also be encrypted thereby adding another layer of security.

PDF Standards

PDF was created by Adobe but is a de-facto industry standard with an association dedicated to manage it, some companies do use propriety and non-standard extensions which can affect the ability for tools to add watermarks to a document. PDF/A is an ISO standard specialized for use in the archiving and long-term preservation of electronic documents.There is also a 3D PDF initiative but clearly this is not applicable for watermarking.

Architecture

Understanding server load issues

PDF documents can vary from a few 100Kb to hundreds of Megabites and can be 1 or hundreds of pages, in addition the paper size can range from millimeters to even meters. Adding a watermark depends on these factors and may take a few milliseconds or many seconds and may require a temporary, but significant, memory usage. As a release process may require many hundreds of documents to be watermarked, it is very important to not put this load on servers that are being used for active work. It is also required that these requests are queued and done asynchronously.

Modern systems use a high granularity of servers to cope with high and uneven loads. The load should therefore be processed by specialized servers that can be both dedicated and located in geographically appropriate area to prevent unnecessary network traffic.

Overview of server configuration

The Wincom watermarking infrastructure uses a hybrid cloud approach. We do not need that the host server requesting the watermark is aware if the server is local or cloud based. It itself may be cloud based but use a dedicated server hosted by the client.

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Clearly using a shared cloud server has an economy of scale, allowing the watermark server to be optimally used. However, performance may not be the only constraint, some clients are under strict regulations e.g. ITAR (International Trade in Arms Regulation) and the PDF must not leave a restricted network. In this case the watermarking server of servers should be hosted in the same network.

Features and Functions

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Conclusion

Wincom´s Watermarking and Stamping solution is a fully automated extension that adapts to any Windchill based business process. Its templates are fully customizable allowing to meet specific business requirements for each user.

Apart from ensuring security, copyright and confidentiality, properly labelled documentation reduces errors and saves large costs related to reworks.

And finally, this extension is cloud based, which provides high performance to large volume of documentation while avoiding the costs of purchasing and maintaining additional servers.

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Article details:
Published date: 28/10/2019 8:14AM
Last updated: 12/05/2020 12:50PM (Simon Heath - simonh@wincom-consulting.com)
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Author: simonh@wincom-plm.com (simonh@wincom-plm.com)
Permalink: https://wex.wincom-plm.com/kb/articles/watermarking-stamping-overview