Cryptographic Device Fast Session Switching
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Solution Overview
Problem
Conventional cryptographic devices experience performance deterioration due to delay times caused by CPU access operations during session switching, as they have smaller data bus sizes compared to block cipher algorithm sizes, leading to inefficient session switch operations.
Innovation Solution
A cryptographic device with a block cipher algorithm executer, an initialization vector manager, and a session round key generator, which store and manage initialization vectors and session keys efficiently, allowing for rapid session switching by minimizing the need for CPU access and optimizing the generation and storage of round keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If CPU is used for session switch operations, then device complexity is reduced, but speed deteriorates due to multiple memory access operations
Solution Approach 1:
The cryptographic device is segmented into distinct functional units: a session switch controller dedicated to managing session switches, a memory unit for storing cryptographic parameters, and a block cipher algorithm executer. This segmentation allows the session switch controller to handle session switching operations independently without requiring multiple CPU memory access operations, thereby resolving the contradiction between simplified device architecture and fast session switching.
Solution Approach 2:
A session switch controller is introduced as an intermediary component between the CPU and the block cipher algorithm executer. This intermediary handles session switching operations by directly accessing and managing cryptographic parameters in the memory unit, eliminating the need for the CPU to perform multiple memory access operations during session switches, thus improving speed while maintaining manageable device complexity.
2Ease of operation
If CPU accesses memory multiple times for session switching, then ease of operation is maintained, but loss of time increases due to access delay
Solution Approach 1:
The session switch controller pre-loads and manages cryptographic parameters (initialization vectors, session keys, round keys) in the memory unit before they are needed for block cipher operations. By preparing these parameters in advance and managing them dedicatedly, the system eliminates time-consuming CPU memory access operations during actual session switching, while maintaining ease of operation through automated parameter management.
Solution Approach 2:
The session switch controller autonomously manages session switching operations by directly accessing the memory unit to retrieve and update cryptographic parameters. This self-service mechanism eliminates the need for CPU intervention in session switching, reducing access delay time while maintaining operational simplicity through automated controller management of the cryptographic parameter lifecycle.
3Speed
If dedicated session switching hardware is added, then speed improves, but device complexity increases
Solution Approach 1:
The session switch controller is designed as a multi-functional unit that not only manages session switching but also handles cryptographic parameter storage, retrieval, and generation. By combining multiple functions into a single dedicated controller, the system achieves fast session switching without proportionally increasing device complexity, as the controller performs multiple roles rather than requiring separate dedicated hardware for each function.
Data Source
AI summary
Provided is a cryptographic device for fast session switching, and more particularly, a cryptographic device using a block cipher algorithm and capable of rapidly performing session switching. The cryptographic device includes: a block cipher algorithm executer for performing encryption or decryption on input data using an initialization vector and a round key corresponding to a current session; an initialization vector manager for storing an initialization vector input from outside of the cryptographic device and an initialization vector received from the block cipher algorithm executer, and providing the initialization vector corresponding to the current session to the block cipher algorithm executer; and a session round key generator for storing a session key input from outside of the cryptographic device, generating the round key based on a session key corresponding to the current session, and providing the round key to the block cipher algorithm executer. The device has a structure capable of performing minimum operation to store and manage an initialization vector and a session key, and thus can minimize delay time caused by session switching.