Replaceable Print Component Controllers Against Power Side-Channel Attacks
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Solution Overview
Problem
Existing communication protocols for replaceable print apparatus components, such as I2C and SPI, are vulnerable to side-channel attacks that compromise security by revealing cryptographic keys through power consumption patterns, and there is a need to enhance power management without compromising security.
Innovation Solution
Implement a secure controller with a power regulator that maintains consistent power consumption within a narrow range during operations and transitions to a low-power state based on a dwell time, using techniques like jamming and smoothing to obscure power consumption patterns, thereby reducing the effectiveness of side-channel attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard communication protocols (I2C/SPI) are used for data transmission, then communication functionality is achieved, but security is compromised due to side-channel attacks revealing cryptographic keys through power consumption patterns
Solution Approach 1:
The patent introduces a power regulator as an intermediary component between the processor and power source. This regulator actively manipulates power delivery to mask the relationship between cryptographic operations and power consumption patterns, thereby preventing side-channel attacks while maintaining secure communication functionality
Solution Approach 2:
The system dynamically changes power consumption parameters by adjusting voltage and current levels through the power regulator. By varying these parameters independently of actual processing activity, the system creates artificial power patterns that do not reveal cryptographic key information, thus resolving the security vulnerability
2Stability of the object's composition
If power consumption is increased to maintain consistent operation, then operational stability is improved, but security against side-channel attacks deteriorates due to more detectable power patterns
Solution Approach 1:
The power regulator independently controls power parameters (voltage, current, timing) to create consistent power delivery patterns regardless of actual processing state. This allows the system to maintain operational stability while simultaneously preventing security compromises, as the power patterns become unrelated to cryptographic operations
3Use of energy by moving object
If the controller transitions to low-power state to save energy, then power consumption is reduced, but communication responsiveness deteriorates
Solution Approach 1:
The controller implements periodic activity by transitioning between active and low-power states in a structured manner. During active periods, full communication functionality is available; during low-power periods, minimal power is consumed. The power regulator ensures secure transitions between states, maintaining security while achieving energy savings through this periodic operation pattern
Data Source
AI summary
Disclosed herein is a secure controller for a replaceable print apparatus component, circuitry for association with a replaceable print apparatus component, and a replaceable print apparatus component. The secure controller is to perform secure communication with a host apparatus via a serial data bus. The controller further is to, in response to a first command from the host apparatus, execute a first operation associated with the first command, wherein the controller is to consume power within a first range during execution of the first operation. The controller also is to, in response to a second command from the host apparatus specifying a dwell time, transition to a low-power state and consume power within a second range in the low-power state for a duration based on the dwell time, the second range being below and spaced apart from the first range.