Dynamic Random Number Buffer Control for Cryptographic Jitter

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Solution Overview

Problem

Control systems face challenges in maintaining secure cryptographic communication due to buffer underflow and jitter issues when dealing with varying data loads and communication cycles, especially under heavy CPU loads, which can impact real-time operations and security enhancements.

Innovation Solution

A control system with a random number storage buffer and dynamic generation of random numbers based on CPU non-utilization rates, buffer remaining amounts, and expected consumption, ensuring each buffer receives the necessary random numbers at the right time to prevent underflow and support encryption boost functions without causing communication jitter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If cryptographic processing is performed at high speed to meet real-time control requirements, then processing speed is improved, but security may be compromised due to insufficient random number availability

Engineering Contradiction:
Improvecryptographic processing speedVSAvoidsecurity reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system generates and stores random numbers in advance in storage units before they are needed for cryptographic processing. The buffer control unit monitors buffer levels and triggers random number generation ahead of time, ensuring that sufficient random numbers are available when high-speed cryptographic processing is required, thus maintaining both speed and security reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system divides the random number management into separate components: random number generation units, multiple storage units with dedicated buffers, and a buffer control unit. This segmentation allows independent optimization of each component - generation can occur asynchronously, storage can be managed separately, and cryptographic processing can proceed at high speed without waiting for random number generation

Inventive Principle:
Principle #1Segmentation

2Reliability

If random numbers are generated and stored in advance for each communication destination, then security is improved, but device complexity increases due to multiple storage buffers

Engineering Contradiction:
Improvesecurity reliabilityVSAvoidbuffer management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The buffer control unit serves multiple functions: it monitors buffer levels across all storage units, determines when to trigger random number generation, manages the distribution of generated random numbers to appropriate storage units, and coordinates with the random number generation units. This universal control mechanism reduces overall system complexity despite having multiple storage buffers

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The buffer control unit continuously monitors the buffer storage levels in each storage unit and uses this feedback information to dynamically control random number generation. When buffers reach threshold levels, the control unit triggers generation; when buffers are full, it prevents generation. This feedback mechanism automates buffer management and reduces complexity compared to static allocation schemes

Inventive Principle:
Principle #23Feedback

3Productivity

If the same random number sequence is reused for different target data, then processing efficiency is improved, but security is compromised

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidcryptographic security
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system allocates dedicated random number sequences to each communication destination (transmission destination or reception source). Each storage unit maintains separate buffers for different destinations, ensuring that random numbers are never reused across different communication contexts. This local quality assurance maintains cryptographic security while allowing efficient parallel processing for multiple destinations

Inventive Principle:
Principle #3Local quality

4Reliability

If cryptographic processing is performed under heavy CPU load, then security maintenance is attempted, but communication jitter occurs due to buffer underflow

Engineering Contradiction:
Improvesecurity maintenanceVSAvoidcommunication stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system performs random number generation in advance and stores them in buffers before cryptographic processing is needed. The buffer control unit ensures that sufficient random numbers are pre-generated and stored, so even when the CPU is heavily loaded with control operations, the cryptographic processing can proceed without waiting for random number generation, preventing buffer underflow and communication jitter

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The buffer storage units act as a cushion between random number generation and cryptographic processing. By maintaining buffer stocks of random numbers, the system creates a safety margin that absorbs variations in processing timing and CPU load, preventing buffer underflow and ensuring stable communication timing even under heavy operational loads

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2902936B1Information processing apparatus
Publication Date: 2019.04.17 HITACHI LTD
  • EP2902936B1 patent drawingFigure 1
  • EP2902936B1 patent drawingFigure 2
  • EP2902936B1 patent drawingFigure 3

AI summary

An object of the present invention is to control buffers so that suitable amounts of generated random numbers are assigned to suitable buffers at a suitable timing, and to store random numbers for encryption boost suitably into a relevant buffer depending on the communication destination. A control device constituting a control system includes: buffers that store random numbers in accordance with communication destinations; a random number generation unit having a storage buffer control unit, a buffer remaining mount monitoring unit and a load condition monitoring unit; and an online cryptographic processing unit. On the basis of the input of CPU non-utilization rate, the remaining amount of random numbers in the random number buffer for each communication destination, information about whether each of the buffers supports encryption boost, and the amount of random numbers expected to be consumed within a predetermined time period, the control device dynamically generates random numbers needed by all buffers in a predetermined time period, calculates the amount of random numbers needed by each buffer, and supplies each buffer with a necessary amount of generated random numbers.