Exploring Substitutes for Confidential Watermarks on Documents: The Rise of Steganography

Introduction

For a considerable time, confidential watermarks have been deployed to protect sensitive documents and discourage unauthorized sharing. As technology progresses, novel tactics surface that offer alternative ways of securing confidential information.

This piece explores the advantages and drawbacks of replacing conventional confidential watermarks, delving into the captivating domain of steganography as an intriguing substitute.

Watermarks vs Substitutions

In today's world of online sharing and ubiquitous access to sensitive documents of all kinds - digital or physical - watermarking is one of the most widely used methods of protecting them from misuse or unauthorized reproduction attempts by unscrupulous actors.

The technology has evolved since its inception and now serves an extremely important role in document chain-of-custody management along with providing assurance on verifiability and origin authentication purposes.

However, watermarks come with certain inherent challenges that need to be considered before adopting them.

Certain irritants, like aesthetics spoilage, reduced readability profiles, diminishing effectiveness against motivated adversaries, tracking glitches, and misinterpretation issues among other concerns could impact their efficacy.

Moreover, watermarks can simply be erased, rendering the document anonymous once again.

To address the anonymity concerns of documents, companies employ various approaches for "substitution."

1. Letter Substitution. It involves modifying or replacing specific characters or words within a document. This method utilizes symbols or alternative characters that closely resemble the original ones, making it challenging to detect the substitution with the naked eye. The advantages of letter substitution include its simplicity and ease of implementation. However, it may not guarantee foolproof protection, as advanced algorithms and OCR tools can potentially identify the changes.

   
   

2. Font Changes. This method involves altering the font or typography of the text, creating a visual distinction from the original document. By using a different font style, size, or weight, the appearance of the document can be significantly changed. This technique offers a straightforward way to differentiate between the original and unauthorized copies. However, it may not be entirely effective, as copying software and OCR tools can still recognize the textual content, making the protection mechanism less reliable.

   
   

3. Steganography. But not directly related to the letters themselves and font substitution. However, more sophisticated methods of concealing changes are used, invisible to the naked eye at the document level.

Steganography for Confidential Documents

In essence, steganography is not something new or unusual. It has long been used in various industries, including document protection. Here are its positive aspects: invisibility and resistance to detection.

In addition to using steganography to protect images through pixel modifications, for videos by modifying specific frames or altering the least significant bits of the video stream, and for audio, it is an excellent tool for document protection.

For such a case, the most commonly used technique is manipulation of whitespaces.

This approach seems obvious, but its logical implementation is rarely observed in the market. It is mostly used on a limited scale or even manually.

Many have probably read about the case, where Elon Musk mentioned using a technique called "binary signature" with additional spaces between sentences in emails for added protection and quick source identification in case of leaks.

This way, they can easily determine who compromised the email.

But what if we expand this approach and make it more scalable and automated, covering not only email messages but also any text-containing materials, documents, presentations, contracts, etc.?

Such a solution will be possible with the existence of an algorithm that allows on-the-fly modification of documents, creating unique copies associated with specific users for each request.

According to calculations based on an existing similar algorithm (which recently appeared on the market), it is already possible to create over 200 trillion copies with no duplicates among the modifications for a single document page.

This approach will enable the processing of large volumes of documentation while offering the company the opportunity to conduct an investigation within minutes in the event of a leak and determine the source of the leak, including the individual's identity, based on the leaked document fragment.

For a more comprehensive implementation of such a marking algorithm through steganographic modifications, it may be possible to reduce the time required for investigations, such as in the case of a leak in the Supreme Court.

Despite conducting an investigation for 8 months, the perpetrator who leaked the document could not be found.

Conclusion

Essentially, the development of such technology and its further implementation in various document management systems and document-sharing platforms is a step towards more transparent handling of sensitive documentation and a more responsible approach to such materials.