Satellite Key Management via PKI and Semi-Mutual Authentication
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Solution Overview
Problem
Current space communication systems face challenges in securely managing encryption keys between a ground control segment and satellites, particularly due to the persistence of secret keys and the complexity of key distribution, which compromises confidentiality and integrity over the satellite's lifespan.
Innovation Solution
Implementing a public key infrastructure (PKI) based on digitally signed certificates and semi-mutual authentication, where the satellite uses self-signed certificates and physical parameters for authentication, eliminating the need for pre-shared secret keys and simplifying key management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symmetric secret-key cryptography is used with pre-shared keys, then communication security is established, but key management complexity and operational constraints increase significantly
Solution Approach 1:
The patent introduces a Certificate Authority (CA) as an intermediary that issues digital certificates to both the ground control segment and the satellite. These certificates contain public keys and serve as trusted intermediaries for key exchange, eliminating the need for complex pre-shared key management while maintaining security through the CA's signed certificates.
Solution Approach 2:
The patent replaces the manual, physical key distribution mechanism (requiring accredited personnel and secure transport) with an automated cryptographic system using asymmetric cryptography and digital certificates. This substitution eliminates the need for physical key injection and manual distribution chains.
2Ease of operation
If secret keys are generated once at the beginning of the mission, then key distribution is simplified, but the principle of creating keys only when needed is violated and security is compromised
Solution Approach 1:
The patent implements dynamic key generation where secret keys are created on-demand during each communication session between the ground control segment and the satellite. The asymmetric cryptography protocol allows keys to be generated, exchanged, and invalidated dynamically, ensuring keys exist only when needed rather than being statically pre-distributed.
Solution Approach 2:
The patent performs preliminary setup by distributing only public keys and digital certificates through the CA infrastructure before mission operations begin. The actual secret keys are then generated dynamically during operations, combining preliminary public key distribution with on-demand secret key creation.
3Reliability
If pre-shared secret keys are used, then initial authentication is possible, but the security of communications depends on the persistence of these keys throughout the satellite's lifespan
Solution Approach 1:
The patent employs ephemeral secret keys that are generated for each communication session and then discarded. These short-lived keys replace persistent pre-shared keys, ensuring that even if one session key is compromised, it does not affect the security of other sessions. The asymmetric cryptography infrastructure enables continuous authentication without relying on long-term secret key persistence.
4Reliability
If manual key distribution chains with accredited personnel are implemented, then key confidentiality is maintained, but operational constraints and complexity increase
Solution Approach 1:
The patent replaces the manual, human-operated key distribution chain with an automated cryptographic system. Public keys and certificates are distributed electronically through secure channels managed by the CA infrastructure, eliminating the need for accredited personnel to physically transport and inject keys into satellites.
Solution Approach 2:
The satellite and ground control segment autonomously perform key generation and authentication operations using the asymmetric cryptography protocol and CA-issued certificates. The system serves itself by automatically establishing secure communications without requiring manual intervention for key management operations.
Data Source
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AI summary
The present invention proposes a key management method for establishing secure communications between a ground control center and an orbiting satellite. During a phase when the satellite is on the ground, the method enables the operation of an asymmetric cryptography protocol with a certification authority. This allows for the deployment, on cryptographic equipment at the ground control center, of a ground private key and a certificate signed by the certification authority, containing a ground public key; and on cryptographic equipment on the satellite on the ground, of a certificate self-signed by the certification authority, containing a public CA of the certification authority. During a phase when the satellite is in orbit, the method enables the operation of a semi-mutual authentication protocol between the ground control center and the satellite, authenticating the satellite by one or more physical characteristics that identify it.