Elevator Controller Key Exchange for Secure Group Communication
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Solution Overview
Problem
Existing elevator systems face vulnerabilities in secure data communication between controllers, as they are either complex to manage or susceptible to security breaches due to shared encryption keys, compromising the security and efficiency of elevator operations.
Innovation Solution
A method is introduced where encryption key pairs are dynamically generated for each elevator controller during commissioning, with public keys shared and private keys stored securely, ensuring secure data communication without pre-established encryption, thus avoiding the risks associated with globally shared keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption is implemented in elevator controller communication, then data communication security is improved, but key management complexity increases
Solution Approach 1:
The patent applies preliminary action by generating and distributing all encryption key pairs before the elevator group is commissioned. Each controller receives its public key in advance during a key distribution phase, so that when operational encryption is activated, the key management infrastructure is already in place. This prevents the need for complex real-time key management during elevator operations.
Solution Approach 2:
The patent segments the key management process into distinct phases: key generation, key distribution, and operational encryption. By separating these functions, the system avoids the complexity of unified key management. Each controller independently manages its own key pair while following standardized protocols for distribution and usage, reducing overall system complexity.
2Ease of manufacture
If shared encryption keys are used across elevator group, then implementation simplicity is improved, but vulnerability to security breaches increases
Solution Approach 1:
The patent applies asymmetry by using asymmetric encryption (public-private key pairs) instead of symmetric encryption with shared keys. Each controller has a unique private key that never leaves the device and a public key that is distributed to other controllers. This asymmetric approach maintains implementation simplicity through automated key management while eliminating the security vulnerability of shared keys, as compromising one controller's key pair does not affect others.
3Adaptability or versatility
If encryption key pairs are generated during commissioning, then installation flexibility is improved, but commissioning process complexity increases
Solution Approach 1:
The patent applies self-service by enabling controllers to automatically generate their own key pairs during commissioning without requiring manual cryptographic configuration. The commissioning system triggers key generation and distribution automatically, and controllers self-configure their encryption settings. This maintains installation flexibility for different elevator group configurations while reducing commissioning complexity through automation.
4Ease of operation
If unrestricted initial communication is allowed during installation, then ease of installation is improved, but security risk during operation increases
Solution Approach 1:
The patent applies dynamics by implementing a transitional state during commissioning where communication is unrestricted, followed by an automated transition to encrypted communication once key distribution is complete. The system dynamically adjusts its security posture based on the commissioning phase, allowing ease of installation during setup while ensuring security is activated before operational use begins.
Data Source
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AI summary
A method for establishing a secure data communication between a plurality of controllers (5) in each of a plurality of elevators (3) of an elevator group (1) is proposed. Therein, the elevators (3) have been initially installed without any encryption being established in communicating data between their controllers (5). Before commissioning the elevator group (1), an encryption establishing step (19) is executed for establishing data encryption in future data communication between the plurality of controllers (5), the encryption establishing step (19) comprising: - initiating, upon receiving a "prepare security" command, generation of a random encryption key pair in each of the controllers (5); - each of the controllers (5) storing its generated private key and advertising its identity and its public key to the controllers (5) of all other elevators (3); - each of the controllers (5) storing the public keys obtained upon advertising from the other controllers (5); - finalizing the encryption establishing step (19) upon lapsing of a predetermined time period since starting the encryption establishing step or occurrence of a finalising event. After finalizing the encryption establishing step (19), no obtaining and storing of further public keys is accepted in each of the controllers (5) and future data communication between the plurality of controllers (5) is established by encrypting a data communication package using the dynamically generated encryption key pairs.