![ Side-channel attack - hardware cryptanalytic
techniques which exploits the physical
behavior of an IC to extract secrets implied in
cryptographic operations. [4]
◦ Timing
◦ Power consumption
◦ Electromagnetic emission [3]
3](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-3-320.jpg)
![ Power Analysis Attack – technique which
involves examining the power consumed by a
device running public-key cryptographic
algorithms over time. [3]
4](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-4-320.jpg)
![ A technique that involves directly interpreting
power consumption measurements (i.e.
traces) collected during cryptographic
operations. [2]
5](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-5-320.jpg)
![ A statistical method for analyzing sets of
measurements to identify data-dependent
correlations. [2]
6](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-6-320.jpg)
![ Device instrumentation
◦ Smart card: R in series with ground line
◦ FPGA: R in series with Vcc [2]
7](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-7-320.jpg)
![ Measurement
◦ Power traces are recorded while device performs
cryptographic operations and stored on a PC.
Signal processing (optional)
◦ Isolate/highlight signal and reduce noise.
Prediction and selection function generation
◦ Used to assign traces to subsets
◦ Typically based on an educated guess as to a
possible value for one or more intermediates within
a cryptographic calculation.
◦ Selection function is single bit (0/1) or multi-bit. [2]
8](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-8-320.jpg)
![ Averaging
◦ the averages of the input trace subsets defined by
the selection function outputs.
Evaluation
◦ Large peaks in the trace = correct guess
◦ Small peaks = incorrect guess [2]
9](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-9-320.jpg)
![ Moradi, Barenghi, Kasper, and Paar used DPA
to extract the secret key of a triple DES
bitstream encryption from a Virtex-II Pro
XC2CP7 FPGA
Time: 3 minutes
Traces: 25,000 [5]
10](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-10-320.jpg)
![ Leakage reduction
◦ Factor k decrease in SNR = k2 increase in number of
traces
Balancing
◦ Make power less dependent on data/operations [2]
Masking – conceal x with mask m
◦ Boolean mask: xm = x 𝑚
◦ Arithmetic mask:
𝑥 𝑚 = 𝑥 + 𝑚 𝑚𝑜𝑑 𝑛
𝑥 𝑚 = 𝑥 × 𝑚 (𝑚𝑜𝑑 𝑛) [1]
11](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-11-320.jpg)
![[1] Danger, J. L., Guilley, S., Barthe, L., Benoit, P. (2011). Countermeasures
against physical attacks in FPGAs. Security trends for FPGAS (pp.
73-100) Springer.
[2] Kocher, P., Jaffe, J., Jun, B., & Rohatgi, P. (2011). Introduction to
differential power analysis. Journal of Cryptographic Engineering,
1(1), 5-27.
[3] Li, H., Wu, K., Xu, G., Yuan, H., & Luo, P. (2011). Simple power analysis
attacks using chosen message against ECC hardware
implementations. Paper presented at the Internet Security
(WorldCIS), 2011 World Congress on, 68-72.
[4] Lomne, V., Dehaboui, A., Maurine, P., Torres, L., & Robert, M. (2011).
Side channel attacks. Security trends for FPGAS (pp. 47-72)
Springer.
[5] Moradi, A., Barenghi, A., Kasper, T., & Paar, C. (2011). On the
vulnerability of FPGA bitstream encryption against power
analysis attacks: Extracting keys from xilinx virtex-II FPGAs. Paper
presented at the Proceedings of the 18th ACM Conference on
Computer and Communications Security, 111-124.
mobile devices. Paper presented at the Proceedings of the World
Congress on Engineering, 1
12](https://image.slidesharecdn.com/85eb6e17-2175-4c11-b261-1e9c590c24d8-160520031359/85/Power-Analysis-Attacks-12-320.jpg)
Power Analysis Attacks
- 2. Background Simple Power Analysis (SPA) Attacks Differential Power Analysis (DPA) Attacks Stages of a DPA Attack Example Countermeasures References 2
- 3. Side-channel attack - hardware cryptanalytic techniques which exploits the physical behavior of an IC to extract secrets implied in cryptographic operations. [4] ◦ Timing ◦ Power consumption ◦ Electromagnetic emission [3] 3
- 4. Power Analysis Attack – technique which involves examining the power consumed by a device running public-key cryptographic algorithms over time. [3] 4
- 5. A technique that involves directly interpreting power consumption measurements (i.e. traces) collected during cryptographic operations. [2] 5
- 6. A statistical method for analyzing sets of measurements to identify data-dependent correlations. [2] 6
- 7. Device instrumentation ◦ Smart card: R in series with ground line ◦ FPGA: R in series with Vcc [2] 7
- 8. Measurement ◦ Power traces are recorded while device performs cryptographic operations and stored on a PC. Signal processing (optional) ◦ Isolate/highlight signal and reduce noise. Prediction and selection function generation ◦ Used to assign traces to subsets ◦ Typically based on an educated guess as to a possible value for one or more intermediates within a cryptographic calculation. ◦ Selection function is single bit (0/1) or multi-bit. [2] 8
- 9. Averaging ◦ the averages of the input trace subsets defined by the selection function outputs. Evaluation ◦ Large peaks in the trace = correct guess ◦ Small peaks = incorrect guess [2] 9
- 10. Moradi, Barenghi, Kasper, and Paar used DPA to extract the secret key of a triple DES bitstream encryption from a Virtex-II Pro XC2CP7 FPGA Time: 3 minutes Traces: 25,000 [5] 10
- 11. Leakage reduction ◦ Factor k decrease in SNR = k2 increase in number of traces Balancing ◦ Make power less dependent on data/operations [2] Masking – conceal x with mask m ◦ Boolean mask: xm = x 𝑚 ◦ Arithmetic mask: 𝑥 𝑚 = 𝑥 + 𝑚 𝑚𝑜𝑑 𝑛 𝑥 𝑚 = 𝑥 × 𝑚 (𝑚𝑜𝑑 𝑛) [1] 11
- 12. [1] Danger, J. L., Guilley, S., Barthe, L., Benoit, P. (2011). Countermeasures against physical attacks in FPGAs. Security trends for FPGAS (pp. 73-100) Springer. [2] Kocher, P., Jaffe, J., Jun, B., & Rohatgi, P. (2011). Introduction to differential power analysis. Journal of Cryptographic Engineering, 1(1), 5-27. [3] Li, H., Wu, K., Xu, G., Yuan, H., & Luo, P. (2011). Simple power analysis attacks using chosen message against ECC hardware implementations. Paper presented at the Internet Security (WorldCIS), 2011 World Congress on, 68-72. [4] Lomne, V., Dehaboui, A., Maurine, P., Torres, L., & Robert, M. (2011). Side channel attacks. Security trends for FPGAS (pp. 47-72) Springer. [5] Moradi, A., Barenghi, A., Kasper, T., & Paar, C. (2011). On the vulnerability of FPGA bitstream encryption against power analysis attacks: Extracting keys from xilinx virtex-II FPGAs. Paper presented at the Proceedings of the 18th ACM Conference on Computer and Communications Security, 111-124. mobile devices. Paper presented at the Proceedings of the World Congress on Engineering, 1 12
- 13. Questions? 13