Written By: Kris Tiri and Ingrid Verbauwhede
Presented By: William Whitehouse
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Purpose
Wave Dynamic Differential Logic
Differential Pair Routing
Proposed Design Flow
Experimental Results
Comments
Small integrated circuits are vulnerable to
side-channel attacks (SCA). The authors
present a digital VLSI design flow to create
secure power-analysis-attack-resistant ICs.
The proposed design flow uses a technique to
balance the power consumption of the logic
gates. It is independent of the cryptographic
algorithm or arithmetic implemented.
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Wave Dynamic Differential Logic (WDDL) was chosen
for its constant power consumption
WDDL Library contains 37 of 53 basic logic functions
WDDL AND-OR-INVERT
example
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Demonstration of the output voltage for a
WDDL gate:
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Load capacitances of differential outputs
must be matched to achieve constant power
consumption
Load capacitance is made of:
◦ Intrinsic output capacitance
◦ Interconnect capacitance
◦ Intrinsic input capacitance
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With the shrinking of the channel length of
the transistors the interconnect capacitance
becomes the dominant capacitance
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The WDDL true and false output
interconnects are routed in parallel such that
they are:
◦ on adjacent tracks of the routing grid
◦ on the same layers
◦ the same length
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Interconnect must have the same parasitic
effects (resistance and capacitance)
Interconnects must be routed to control
crosstalk
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To add the differential pair routing to the
secure design flow the authors split the
routing into two steps:
◦ Fat Wire Routing
◦ Interconnect Decomposition
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This figure illustrates the interconnect
decomposition:
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Variation of the input
capacitance of true/false
WDDL gates is within 10%
Variation between
true/false interconnect
capacitance of differential
pair routing is within 20%
Variation between
true/false interconnect
capacitance of regular
routing of true/false gates
is 50%
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The following is the authors’ proposed secure
digital design flow:
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New stages include Cell Substitution and
Interconnect Decomposition:
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Subset of DES algorithm
Secure
Reference
Size (um2)
12880
3782
Mean Energy
Consumption (pJ)
27.1
4.6
Normalized Energy
Deviation
6.6%
60%
Normalized Standard
Deviation
0.9%
12%
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A differential power analysis (DPA) attack was
performed on the two designs.
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Secure and Insecure AES Core were design
and fabricated on the same die:
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Good case for use of differential gates
Designs SCA resistant ICs
Easy to add into digital design flow and not
much overhead
Independent of cryptographic algorithm
Larger area and power consumption
Much Lower throughput
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Only use WDDL gates and differential pair
routing on some blocks of the design
The WDDL library only has 70% of basic logic
functions in a standard cell library
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If you have any questions please email me at:
wdwhiteh@iastate.edu