Text Document Data Hiding via Inter-Character Spacing
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Solution Overview
Problem
Existing steganography techniques for text documents are not resilient to printing and photocopying, and lack high data hiding capacity and self-verifiability, making it difficult to prevent unauthorized disclosure of sensitive information.
Innovation Solution
A method that encodes information in text documents by altering inter-character spaces to integral or non-integral multiples of a reference length, allowing for high-capacity data hiding that remains retrievable even after printing and photocopying, and is self-verifiable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional steganography techniques are used in text documents, then data hiding is achieved, but the method is not resilient to printing and photocopying
Solution Approach 1:
The patent changes the parameter of inter-character spacing in text documents to encode hidden data. By modifying the space between characters rather than the characters themselves, the method creates a encoding that survives printing and photocopying processes, as these physical reproduction methods preserve spatial relationships between elements.
2Quantity of substance
If dot encoding is used for data hiding, then high data hiding capacity is achieved, but the method is vulnerable to photocopying
Solution Approach 1:
Instead of encoding data in the vertical dimension (dot patterns within characters) which is vulnerable to photocopying, the patent uses the horizontal dimension (inter-character spacing) which remains intact during photocopying. This dimensional shift provides both high data capacity and resistance to photocopying attacks.
3Reliability
If syntactic methods are used for data hiding, then resilience to printing and photocopying is achieved, but data capacity is low
Solution Approach 1:
The patent applies partial action by encoding data in only the inter-character spaces of text documents, leaving the characters themselves unchanged. This partial modification approach maintains document readability and aesthetics while achieving both high data capacity and resilience to copying, as the unchanged characters preserve their original appearance through printing and photocopying.
4Quantity of substance
If inter-character space is altered for encoding, then data hiding capacity is increased, but the alteration may be detectable
Solution Approach 1:
The patent applies local quality by making very small, localized adjustments to inter-character spacing rather than large alterations. These subtle local modifications are sufficient to encode data but remain imperceptible to the human eye, maintaining the natural appearance of the text document while achieving high data hiding capacity.
Data Source
AI summary
The present invention relates to a method and system of embedding data in text documents. The method includes obtaining a document having dimensions and at least a first character and a second character and determining a length between the first character and the second character to define an inter-character space. A reference length is determined, where the reference length is a function of the dimensions of the text document. A threshold length is determined, where the threshold length is a minimum length wherein information is not encoded in the inter-character space if the inter-character space is not within the threshold length. The information is encoded into an altered inter-character space wherein a length of the altered inter-character space is an integral multiple of the reference length or a non-integral multiple of the reference length.