Pattern-Free Encryption for Video Stream Header Preservation
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Solution Overview
Problem
Current encryption methods may generate ciphertext that includes reserved patterns, making it difficult to distinguish between record headers and encrypted payloads, especially in video streaming formats like MPEG, where preserving clear headers is essential for search capabilities.
Innovation Solution
A method and system that apply a cipher to an input stream, generating an intermediate stream and then converting it to an output stream by comparing groups of symbols to a reserved pattern, substituting input symbols for output symbols when a match is found, ensuring the reserved pattern only appears at its original locations, using techniques like OFB or CFB mode encryption with a feedback loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard encryption modes (OFB, CFB) are used to encrypt the entire stream, then encryption coverage is complete, but reserved patterns may accidentally appear in the ciphertext making header identification difficult
Solution Approach 1:
The encryption system segments the data stream into distinct portions: headers are excluded from encryption while payloads are encrypted. This segmentation allows headers to remain identifiable with their reserved patterns intact, while still providing encryption protection for the payload portions. The system processes these segments differently through the encryption pipeline.
Solution Approach 2:
Different parts of the data stream receive different treatment: headers maintain their original unencrypted form with reserved patterns preserved for easy identification, while payloads undergo full encryption. This local differentiation ensures that header identification remains reliable without requiring complex modifications to the overall encryption architecture.
2Ease of operation
If headers are left unencrypted to preserve reserved patterns, then header identification is easy, but security coverage is reduced
Solution Approach 1:
The data stream is divided into headers and payloads, with each segment receiving appropriate processing. Headers remain unencrypted to preserve reserved patterns for easy identification and synchronization, while payloads are fully encrypted to maintain security. This segmentation resolves the conflict between operational ease and security coverage.
Solution Approach 2:
The encryption system acts as an intermediary that selectively applies encryption based on data type. It identifies header portions and preserves them in clear form while encrypting payload portions, thus mediating between the need for easy header identification and comprehensive security coverage.
3Reliability
If pattern substitution is implemented to prevent reserved patterns in ciphertext, then header identification is reliable, but processing complexity increases
Solution Approach 1:
The system extracts reserved patterns from the encryption process by excluding header portions containing these patterns from encryption. Instead of attempting to prevent pattern formation through complex substitution mechanisms, the system simply takes out the header portions and processes them separately, maintaining reliability while minimizing processing complexity.
Solution Approach 2:
Instead of trying to ensure reserved patterns do not appear in ciphertext through complex substitution, the invention inverts the approach by ensuring reserved patterns appear only in unencrypted header portions. This inversion simplifies the system by eliminating the need for complex pattern substitution logic while maintaining reliable header identification.
Data Source
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AI summary
A method is described for defining a reserved pattern of symbols, receiving in a crypto-module an input stream including sequential input symbols, applying a cipher to the input stream in the crypto-module so as to generate an intermediate stream including sequential output symbols corresponding respectively to the input symbols, and converting the intermediate stream to an output stream from the crypto-module by comparing successive groups of the input symbols and the corresponding output symbols to the reserved pattern and, upon finding a match to the reserved pattern in a given group, substituting the input symbols in the group into the intermediate stream in place of the corresponding output symbols. Related hardware and systems are also described.