Probabilistic Encrypted File Identification via Size Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current systems face challenges in efficiently identifying the contents of encrypted files during transfers, leading to overly restrictive or permissive default rules, as they cannot accurately determine whether to allow or restrict the transfer of encrypted files.
Innovation Solution
A method and system that probabilistically determine the contents of an encrypted file by comparing its size to a file size table containing unencrypted file sizes and ranges, adjusting for compression, to enforce transfer rules associated with the unencrypted file.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If default system rules restrict all encrypted file transfers, then security is improved, but user convenience deteriorates due to overly onerous restrictions
Solution Approach 1:
The system changes the parameter of file identification from binary (encrypted/unencrypted) to probabilistic (confidence score based on size matching), allowing nuanced decision-making that balances security and convenience
Solution Approach 2:
The system applies partial action by only attempting to identify files where size matching provides reasonable confidence, rather than attempting to identify all encrypted files, thus avoiding excessive restrictions while maintaining security where feasible
2Ease of operation
If default system rules allow all encrypted file transfers, then user convenience is improved, but security deteriorates due to overly permissive restrictions
Solution Approach 1:
The system introduces a confidence score parameter to quantify the likelihood of file identification, enabling security decisions based on probabilistic evidence rather than binary assumptions
Solution Approach 2:
The system applies selective identification only when size matching provides sufficient confidence, allowing convenient transfer of clearly identifiable files while maintaining security scrutiny for ambiguous cases
3Measurement precision
If comprehensive compression analysis is performed on encrypted files, then identification accuracy is improved, but computational complexity and time increase
Solution Approach 1:
The system extracts only the file size parameter as an identifying characteristic, discarding the need for comprehensive compression analysis while retaining sufficient identification capability for many cases
Solution Approach 2:
The system pre-computes and stores size ranges for unencrypted files, enabling rapid comparison against encrypted file sizes without performing compression analysis during the transfer decision process
Data Source
AI summary
A mechanism for probabilistically determining the contents of an encrypted file is provided, such that a transfer of the encrypted file can be restricted according to rules associated with an unencrypted version of the file. Embodiments generate a file size table of a subset of files, where each entry of the file size table includes a size information regarding the unencrypted file. Embodiments compare the size of the encrypted file against the file sizes and compressed file size ranges to determine whether the encrypted file has a match. If the size of the encrypted file has a single match in the table, then there is a high probability that the file associated with the matching entry is the unencrypted version of the encrypted file. Rules associated with restricting access of the file related to the matching entry can be used to control transfer of the encrypted file.