Secure Iterative Processing Protocol for Encrypted Signal Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current homomorphic cryptosystems face challenges in securely executing iterative or adaptive filtering algorithms due to the 'cipher blowup' problem, where encrypted numbers exceed the representable range, and there is a lack of solutions for privacy-preserving adaptive filtering in the Signal Processing in the Encrypted Domain.
Innovation Solution
Implementing a secure iterative processing protocol that uses homomorphic linear processing, rescaling modules, and adaptive filtering algorithms directly on encrypted signals, combining homomorphic encryption with garbled circuits and interactive secure protocols to avoid cipher blowup and ensure privacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If homomorphic encryption is used for secure signal processing, then data privacy is preserved, but cipher blowup occurs after a given number of iterations
Solution Approach 1:
The patent introduces a trusted third party (TTP) as an intermediary that holds the secret key and performs controlled decryption operations. This mediator enables secure iterative processing by decrypting intermediate results at specific stages, preventing cipher blowup while maintaining overall data privacy through the TTP's controlled access to plaintext information
Solution Approach 2:
The patent segments the iterative processing into multiple stages, with controlled decryption points between iterations. Instead of maintaining encryption throughout the entire processing chain, the system divides the computation into encrypted segments followed by controlled decryption and re-encryption phases, managing cipher size at each segment while preserving security
2Adaptability or versatility
If adaptive filtering algorithms are applied to encrypted signals, then processing flexibility and responsiveness are improved, but existing homomorphic cryptosystems cannot directly handle them due to cipher blowup
Solution Approach 1:
The trusted third party acts as a mediator that enables adaptive filtering on encrypted signals by performing controlled decryption of intermediate results. This allows the system to maintain the flexibility and responsiveness of adaptive filtering algorithms while managing cipher blowup through the intermediary's controlled intervention at specific processing stages
Solution Approach 2:
The patent implements dynamic processing where the encryption/decryption strategy adapts based on the processing stage. Adaptive filtering algorithms operate with varying levels of encryption protection depending on the iteration phase, allowing flexible processing while dynamically managing cipher size through controlled decryption points
3Reliability
If fully homomorphic cryptosystems are used to execute any circuit without decryption, then data privacy is maintained throughout processing, but ciphertext size becomes huge and practical implementation is not feasible
Solution Approach 1:
The patent segments the fully homomorphic processing into controlled phases with intermediate decryption points. Instead of maintaining full homomorphic encryption throughout all iterations, the system divides processing into encrypted segments followed by controlled decryption at the trusted third party, dramatically reducing ciphertext size while maintaining privacy through segmented protection
Solution Approach 2:
The trusted third party serves as an intermediary that enables practical implementation by performing controlled decryption operations. This mediator allows the system to achieve near-full homomorphic functionality with dramatically reduced ciphertext sizes, making the system practically feasible while maintaining data privacy through the intermediary's controlled access
Data Source
AI summary
Disclosed embodiments include methods and apparatuses for secure iterative processing of encrypted signals based on implementing a secure iterative processing protocol that avoids cipher blowup, and applying an iterative algorithm directly on the encrypted signals to generate an encrypted processed output signal. In a particular embodiment, the protocol comprises applying homomorphic linear processing, preparing and applying a rescaling module to avoid cypher blowup, and homomorphically adapting the encrypted signals. Specific embodiments implement iterative adaptive filtering algorithms in the encrypted domain including non-collaborative secure filtering and two-party filtering based on homomorphic encryption, interactive secure protocols, garbled circuits, or a combination thereof.