OFDM Modulated Signature Authentication for Replay-Resistant Links
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Solution Overview
Problem
Current wireless communication technologies face challenges in ensuring robust authentication and integrity, particularly in low-power IoT devices and edge devices, where memory footprint and power consumption are limited, and existing security enhancements may not adequately protect against attacks like replay attacks.
Innovation Solution
The implementation of a modulator and demodulator system using orthogonal frequency division multiplexing (OFDM) that adds a secured signal with a modulated IQ signature to the legacy signal, including a hash and encryption process, to enhance authentication and integrity by using a shared symmetric key for message authentication and incorporating a time stamp for replay detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryptographic protocols (e.g., WPA) are used for security enhancement, then authentication and integrity are improved, but memory footprint and power consumption increase
Solution Approach 1:
The security function is segmented into two parts: a legacy signal path that maintains backward compatibility and a secured signal path that provides enhanced security. The secured path processes only critical authentication data (hash of selected frame portions) rather than entire frames, reducing computational burden and power consumption while maintaining strong authentication.
Solution Approach 2:
The invention extracts only the essential authentication elements from the full cryptographic protocol. Instead of implementing complete cryptographic suites, it extracts the core authentication function by hashing selected portions of frames and comparing hashes, eliminating unnecessary cryptographic overhead that would increase power consumption in IoT devices.
2Reliability
If cryptographic protocols are used for security enhancement, then authentication and integrity are improved, but device complexity increases
Solution Approach 1:
The system is divided into legacy and secured signal paths. The legacy path handles standard communication with existing devices, while the secured path implements simplified authentication using hash comparison. This segmentation allows complex security features to be added without complicating the basic operation of legacy devices.
Solution Approach 2:
Instead of implementing complex cryptographic verification, the system creates a simplified copy of the authentication function using hash values. The hash of selected frame portions serves as a compact representation that can be verified through simple comparison, replacing complex cryptographic operations with lightweight computation.
3Reliability
If a modulated signature is added to all data frames, then authentication is improved, but processing overhead and power consumption increase
Solution Approach 1:
The invention applies partial action by selecting only specific portions of frames (rather than processing entire frames) for hashing and authentication. This selective approach reduces the amount of data that needs to be processed while still providing sufficient authentication coverage for security-critical fields.
Solution Approach 2:
The system extracts only the essential authentication data from frames by selecting specific portions that contain critical information. This extraction reduces the volume of data requiring authentication processing while maintaining security effectiveness for the most important frame elements.
4Reliability
If existing security protocols are used, then basic authentication is provided, but protection against replay attacks is insufficient
Solution Approach 1:
The system performs preliminary action by incorporating timestamps into the hash computation before transmission. This preliminary inclusion of temporal information enables the receiver to verify not only authentication but also freshness of the message, preventing replay attacks where captured packets are retransmitted.
Solution Approach 2:
The system implements feedback through timestamp verification and hash comparison mechanisms. The receiver provides feedback by verifying whether the received timestamp is within an acceptable time window and whether the hash matches the computed hash of received data, enabling detection of replayed or tampered packets.
Data Source
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AI summary
Various embodiments relate to a demodulator configured to receive a legacy signal and a secured signal using orthogonal frequency division multiplexing (OFDM) modulation, including: an analog to digital converter (ADC) configured to receive an OFDM modulated signal; an fast Fourier transform (FFT) unit configured to receive the output of the ADC; a frequency de-mapper configured to map the output of the FFT to legacy frame samples and secured signal samples including a secured hash; a sample to bit converter, a channel deinterleaver, and a channel decoder configured to process the legacy samples to produce a legacy frame; frame checking logic configured to check the validity of the legacy frame and produce a frame validity signal; a de-channelization module configured to convert the sample rate of secured signal samples; a channel decoder configured to decode the converted secured signal bits; a frame selector configured to select specific portions of the input legacy frame to produce a secured frame; a hash module configured to hash and encrypt the secured frame; a hash comparator configured to compare the received secured hash to the hashed and encrypted secured frame configured to produce a hash compare signal; and attack detection logic configured to determine when a received OFDM signal has been attacked based upon the hash compare signal.