A Digital Design Flow for Secure Integrated Circuits

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A Digital Design Flow for Secure Integrated Circuits Powered By Docstoc
					Written By: Kris Tiri and Ingrid Verbauwhede
           Presented By: William Whitehouse
   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.
   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
   Demonstration of the output voltage for a
    WDDL gate:
   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
   With the shrinking of the channel length of
    the transistors the interconnect capacitance
    becomes the dominant capacitance
   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
   Interconnect must have the same parasitic
    effects (resistance and capacitance)
   Interconnects must be routed to control
    crosstalk
   To add the differential pair routing to the
    secure design flow the authors split the
    routing into two steps:
    ◦ Fat Wire Routing
    ◦ Interconnect Decomposition
   This figure illustrates the interconnect
    decomposition:
   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%
   The following is the authors’ proposed secure
    digital design flow:
   New stages include Cell Substitution and
    Interconnect Decomposition:
   Subset of DES algorithm
                          Secure   Reference
    Size (um2)            12880    3782
    Mean Energy           27.1     4.6
    Consumption (pJ)
    Normalized Energy     6.6%     60%
    Deviation
    Normalized Standard   0.9%     12%
    Deviation
   A differential power analysis (DPA) attack was
    performed on the two designs.
   Secure and Insecure AES Core were design
    and fabricated on the same die:
   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
   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
   If you have any questions please email me at:
               wdwhiteh@iastate.edu