Optical Feistel Circuits for Low-Power Bandwidth-Preserving Encryption
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Solution Overview
Problem
Current fiber optic encryption methods require power-hungry devices and are costly to adapt to new modulation methods, limiting the design space for secure optical signal transmission.
Innovation Solution
An optical Feistel encryption circuit using a series of stages with splitters, converters, and phase modulators to encrypt and decrypt signals, maintaining bandwidth and allowing for reversible decryption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital encryption at the logical layer is used, then security is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent replaces electronic digital encryption devices with optical domain encryption components. Specifically, it uses optical modulators, phase shifters, and interferometers to perform encryption operations directly on optical signals, eliminating the need for photoelectric conversion and electronic processing. This substitution of optical components for electronic systems reduces device complexity while maintaining security.
Solution Approach 2:
The patent extracts the encryption function from the electronic logical layer and implements it independently in the optical layer. By separating the encryption operation from the electronic signal processing chain, the system can perform encryption using purely optical components, thereby reducing the complexity of electronic devices while preserving security functionality.
2Reliability
If digital encryption at the logical layer is used, then security is improved, but power consumption increases
Solution Approach 1:
The patent replaces power-hungry electronic encryption devices with passive or low-power optical components. The optical modulators, phase shifters, and interferometers used in the encryption process consume significantly less power compared to FPGA or ASIC-based digital encryption systems, thereby reducing overall power consumption while maintaining security.
Solution Approach 2:
The optical encryption system utilizes the inherent properties of light and optical interference to perform encryption operations without requiring active electronic processing. The interferometric-based encryption leverages the natural wave nature of light to achieve security functions with minimal external power input, enabling the system to operate with reduced power consumption.
3Productivity
If new modulation methods are adopted to increase bit rates, then data rate is improved, but device complexity and cost increase
Solution Approach 1:
The patent develops a universal optical encryption platform that can accommodate various modulation formats (such as QPSK, 16-QAM, 64-QAM) without requiring dedicated encryption devices for each format. The interferometric-based encryption architecture processes optical signals in a format-agnostic manner, allowing a single device to serve multiple high-speed modulation methods, thereby reducing device complexity and cost.
Solution Approach 2:
The patent employs dynamically adjustable optical components, such as programmable phase shifters and reconfigurable interferometers, that can adapt to different modulation schemes and data rates. This dynamic flexibility allows the encryption system to be upgraded or reconfigured for new high-speed modulation methods without replacing the entire encryption device, thus reducing complexity and cost.
4Productivity
If new modulation methods are adopted to increase bit rates, then data rate is improved, but power consumption increases
Solution Approach 1:
The patent replaces electronic signal processing and encryption operations with optical domain processing. By performing encryption directly on optical signals using interferometers and phase modulators, the system eliminates the need for photoelectric conversion and electronic decryption, significantly reducing power consumption even at high data rates achieved through advanced modulation methods.
5Ease of operation
If reversible nonlinear transformations are used for encryption, then decryption is enabled, but design space is reduced
Solution Approach 1:
The patent segments the encryption process into distinct optical stages: initial modulation, nonlinear phase transformation via interferometers, and final encoding. Each stage can be independently designed and optimized, allowing for greater design flexibility. The segmented architecture enables the use of irreversible nonlinear transformations in intermediate stages while maintaining overall system reversibility through carefully designed complementary operations in subsequent stages.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides secure encryption with manageable bandwidth and cost-effective adaptation to new modulation methods, avoiding early obsolescence.
Implementation Method 1
The phase modulator receives the first electrical signal and modulates the second optical Feistel input signal based upon the first electrical signal to provide a first phase modulated signal
Data Source
AI summary
A Feistel encrypter receives optical input signals to be encrypted and outputs encrypted optical output signals. The Feistel encrypter may include any number of stages to achieve a desired level of encryption. Each stage provides two half stages, each including a splitter, a converter, and a phase modulator. The converter converts an optical Feistel input signal into an electrical signal. The phase modulator modulates an optical Feistel input signal based upon the electrical signal to provide a phase modulated signal. First and second phase modulated signals of the first stage are provided to the second and first inputs, respectively, of the next Feistel stage (if any). As the signals undergo transformation at each Feistel stage, the sample-and-hold with proper alignment allows the bandwidth of first and second phase modulated signals to be maintained. Encryption of the signals continues with each subsequent Feistel stage until the final Feistel encryption stage is completed and an encrypted data signal is provided.