Session Key Update for MIPI CSI-2 and DSI-2
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Solution Overview
Problem
The existing CSI-2 and DSI-2 standards do not support key updates for session keys, which is necessary for secure communication in various applications, including mobile devices and IoT systems.
Innovation Solution
An information processing device, mobile device, and communication system are designed with a protection unit that derives and updates session keys using a key schedule, enabling secure encryption and message authentication across multiple communication layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SPDM standard is applied to CSI-2 or DSI-2 standards, then security protection for communication is improved, but the session key cannot be updated which limits long-term security
Solution Approach 1:
The key management process is segmented into multiple distinct phases: initial key derivation from master secret, session key generation and transmission, and periodic key updates. This segmentation allows each phase to be optimized independently, enabling session key updates while maintaining the security structure of the original SPDM standard.
Solution Approach 2:
The master secret is derived in advance from the key schedule during system initialization, before actual communication begins. This preliminary derivation enables subsequent session keys to be generated from this pre-established master secret, allowing for secure key updates without requiring changes to the fundamental key schedule structure.
2Reliability
If a session key transmitted via SPDM-protected communication is used, then communication security is improved, but it requires defining update mechanisms which increases system complexity
Solution Approach 1:
The master secret derived from the key schedule serves as a universal foundation for generating multiple session keys throughout the communication lifecycle. This single master secret can derive numerous session keys using different random inputs, eliminating the need for separate update mechanisms and reducing system complexity while maintaining security.
Solution Approach 2:
The master secret acts as an intermediary between the key schedule and individual session keys. Rather than directly managing multiple session keys or their updates, the system uses the master secret as a mediator that can generate any required session key, simplifying the key management architecture.
Data Source
AI summary
The present disclosure relates to an information processing device, a mobile device, and a communication system capable of updating a session key. A first secret is derived from a key schedule by using first communication including transmission or reception of a command for controlling second communication faster than the first communication or a response to the command, a first session key related to the first secret is derived, the first session key is used for encryption or message authentication of the first communication, a second session key is received, transmitted, or derived by using the first communication, the second session key is used for encryption or message authentication of the second communication, a third session key is received, transmitted, or derived by using the first communication, and the third session key is used instead of the second session key. The present technology can be applied to, for example, a communication system conforming to the MIPI standard.