Homomorphic Encryption Group Key Generation via Trust Server
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Solution Overview
Problem
Existing communication systems face challenges in securely sharing a group key among electronic devices without exposing it to unauthorized elements, particularly in insecure channels, which can lead to unauthorized access or accidental disclosure of information.
Innovation Solution
A communication system and method utilizing homomorphic encryption (HE) where electronic devices share a homomorphic encryption key, generate a Boolean circuit based on the number of devices, and use a server to calculate an HE-evaluated value and random number to create a common session key through homomorphic decryption, ensuring the key is not exposed to the server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a group key is shared among electronic devices through a server in an insecure channel, then key exchange can be facilitated, but the group key may be exposed to unauthorized access or accidental disclosure
Solution Approach 1:
A trust server is introduced as an intermediary that facilitates key exchange without exposing the group key. The server generates and distributes individual encryption keys to each electronic device, and these keys are used to derive the group key locally without the server ever knowing the group key itself. This mediator approach enables secure key exchange while maintaining key security.
Solution Approach 2:
The group key generation process is segmented into individual key components distributed to each device. Instead of sharing one master key, each device receives a unique key segment that can be used to locally derive the group key. This segmentation ensures that no single point of failure exists and the group key remains secure even if individual keys are compromised.
2Reliability
If the group key is protected from exposure to the server, then security is improved, but the server cannot facilitate key management operations
Solution Approach 1:
The trust server acts as a mediator that performs key management operations using individual device keys without ever accessing the group key. The server can facilitate key distribution, updates, and revocation by operating on the segmented key components, thereby maintaining both security and operational capability.
Solution Approach 2:
Each electronic device performs self-service by locally deriving the group key from its individual key component and the server's public information. This eliminates the need for the server to handle the group key directly, maintaining security while enabling key management through automated local operations.
3Reliability
If homomorphic encryption is used to prevent server exposure to the group key, then security is enhanced, but system complexity increases
Solution Approach 1:
The system changes the cryptographic parameters from traditional encryption schemes to homomorphic encryption, which allows computations to be performed on encrypted data. This parameter change enables the server to operate on encrypted key components without decryption, enhancing security while the modular nature of the implementation keeps complexity manageable.
Solution Approach 2:
The traditional mechanical key exchange system where keys are transmitted and managed in plaintext is replaced with a cryptographic system based on homomorphic encryption properties. This substitution eliminates the need for secure key transmission channels and manual key management, reducing operational complexity despite the advanced cryptography used.
Data Source
AI summary
Disclosed are a communication system and an operating method thereof. A plurality of electronic devices for forming a group may be configured to share a homomorphic encryption (HE) key. A server may be configured to generate a Boolean circuit for performing an operation based on input values corresponding to the number of electronic devices. Each of the electronic devices may be configured to transmit an encrypted session ephemeral key to the server through HE. The server may be configured to calculate an HE-evaluated value by applying the encrypted session ephemeral keys as the input values of the Boolean circuit. The server may be configured to transmit the HE-evaluated value and a given random number to each electronic device. Each electronic device may be configured to generate a common session key for the group based on the HE key, the HE-evaluated value and the given random number through homomorphic decryption.