Fuse-Protected Chip Card Attack Detection Circuit
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Solution Overview
Problem
Existing methods for protecting microcircuit cards against physical attacks, such as fault injection, are inadequate as they can be circumvented by attackers, and alternative countermeasures like OTP are limited in their effectiveness.
Innovation Solution
A microcircuit card design that controls the charging of a capacitor in normal operation and uses it to blow a fuse when an attack is detected, preventing the card from functioning, with the control signal switching from high to low to ensure the attacker cannot prevent fuse destruction, utilizing a D flip-flop, inverting gate, and PMOS transistors to manage this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing protection methods are used against physical attacks, then some level of security is provided, but attackers can circumvent these protections
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning a fuse and capacitor system that will automatically activate to destroy the microcircuit card if an attack is detected. The control means are programmed in advance to trigger fuse destruction when abnormal conditions are detected, preventing attackers from circumventing security measures by destroying the card's functionality before the protection mechanism activates.
Solution Approach 2:
The patent converts the harmful effect of an attack into a beneficial security outcome by using the detected attack condition to trigger fuse destruction. The abnormal current or voltage caused by an attack is detected and transformed into the activation signal that blows the fuse, thereby converting the attack's energy into a protective action that permanently disables the card.
2Reliability
If a fuse is used to protect the microcircuit card, then permanent destruction upon attack is achieved, but the timing and detectability of fuse destruction becomes critical
Solution Approach 1:
The patent applies preliminary action by pre-charging a capacitor during normal operation. This stored energy is ready to immediately blow the fuse when the attack detection condition is met, eliminating any time delay between detection and fuse destruction. The control means are also pre-programmed with the detection logic, so no additional processing time is required when an attack occurs.
Solution Approach 2:
The patent implements rushing through by designing the fuse destruction mechanism to occur instantaneously upon attack detection. The pre-charged capacitor provides immediate energy discharge through the fuse, bypassing any gradual degradation or delayed response. This ensures the protection action completes so quickly that attackers cannot intervene or detect the timing of the fuse destruction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents attackers from interfering with the card's operation by ensuring the fuse is blown quickly and undetectably, maintaining the control signal's integrity and securing vital signals like reset, clock, or input/output signals.
Implementation Method 1
a capacitor (140) powered in normal operation by a voltage VCC
Implementation Method 2
discharging the capacitor (140) to blow the fuse (250)
Data Source
Figure 1~2
AI summary
This microcircuit board (200) includes: - means for detecting an attack on the board; and - control means (130) capable of blowing a fuse (250) of the board when an attack is detected.