DMR Voice Superframe Signaling for Embedded Encryption Parameters
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Solution Overview
Problem
The ETSI DMR standard lacks a method for transporting encryption parameters, such as cryptographic keys and initialization vectors, necessary for secure communication between devices, which hinders secure encryption and decryption processes.
Innovation Solution
The solution involves embedding encryption parameters like key IDs, algorithm IDs, and initialization vectors within the vocoder frames and embedded signaling fields of a DMR voice superframe, allowing receiving devices to extract and use these parameters for decryption, ensuring secure communication without interfering with other information transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption parameters are transmitted using existing DMR standard methods, then device compatibility is maintained, but secure encryption cannot be achieved because the standard lacks encryption parameter transport mechanisms
Solution Approach 1:
The patent embeds encryption parameters (IV, key ID, algorithm ID) within existing DMR protocol structures - specifically nesting them in the embedded signaling field and vocoder frame headers. This allows the encryption parameters to be transported within the existing DMR framework without requiring external transport mechanisms, thus maintaining compatibility while enabling secure encryption.
Solution Approach 2:
The patent introduces encryption parameter fields as intermediary elements that bridge the gap between existing DMR communication and secure encryption requirements. These intermediary fields carry the necessary cryptographic information without disrupting the existing DMR protocol flow, enabling both secure encryption and parameter transport simultaneously.
2Reliability
If encryption parameters are embedded in vocoder frames, then parameter transport is enabled, but voice signal quality may be affected
Solution Approach 1:
The patent places encryption parameters in specific localized fields within the vocoder frame structure - using dedicated header fields and embedded signaling regions. This localized embedding ensures that only specific portions of the frame carry encryption information, while the main voice payload remains unaffected, preserving voice signal quality.
3Ease of operation
If encryption parameters are sent in every superframe, then receiving devices can decrypt immediately, but transmission overhead increases
Solution Approach 1:
The patent embeds all necessary encryption parameters (IV, key ID, algorithm ID) in advance within each superframe's vocoder frames and signaling fields. This preliminary inclusion ensures that receiving devices have all required decryption information available immediately upon receiving the encrypted payload, enabling instant decryption without additional overhead transmissions.
Data Source
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AI summary
A transmitting device encrypts DMR voice superframes using encryption parameters and sends (300) the encryption parameters in at least one of the voice superframes by: identifying (302) a selected number of bits from a plurality of vocoder frames the voice superframe; replacing (304) each of the identified bits with a corresponding bit of a first encryption parameter; placing (306) at least one encryption parameter in an embedded signaling field of the voice superframe; and transmitting (308) the voice superframe with the encryption parameters to a receiving device. The receiving device extracts the encryption parameters, which can be a key identifier, an algorithm identifier, and an initialization vector for use in decrypting messages from the transmitting device.