File Tamper Detection via Digital Signature Overlay
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Solution Overview
Problem
Digital signatures in files do not effectively prevent document fraud when the content changes, as the altered content remains visible, and existing solutions fail to ensure that the signature block is not printed or obscured if the signature is deemed invalid.
Innovation Solution
A system comprising a digest module to create a digital signature, a comparator module to check for changes, and a watermark module to overlay or obscure the file contents with a mark when the signature is invalid, ensuring that the file contents are only visible if the signature is valid, and are obscured or hidden if it is invalid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a digital signature is included in a document to provide document integrity, then document security is improved, but the user must actively look for the signature block to determine validity, reducing ease of operation
Solution Approach 1:
The patent applies visual indicators (color changes, marks, or overlays) on the document content to indicate whether a digital signature is valid or invalid. When the signature is invalid or the document has been altered, a visual mark is displayed to alert the user immediately, eliminating the need to actively search for the signature block.
2Loss of information
If the altered content remains visible after signature validation fails, then information accessibility is maintained, but document fraud prevention is reduced
Solution Approach 1:
The patent applies preliminary anti-action by preemptively blocking or obscuring the document content when an invalid signature is detected. Instead of allowing the altered content to remain visible and then warning the user, the system prevents access to the content by displaying a blocking mark or overlay, thereby preventing potential fraud before it can be acted upon.
Data Source
AI summary
This disclosure relates generally to methods and systems for determining when a file has changed. According to one aspect of the present disclosure, a method of determining if contents of a file have changed can include determining if a digital signature created as a function of contents of the file has changed, and when the digital signature has changed, overlaying the contents of the file with a first mark that indicates the contents have changed and blocks a view of the contents of the file.