CHES Rump Session, September, 15th, 2015

Korea University Seokhie Hong, Taewon Kim, Sangyub LEE

Most Important thing in black box test

CHIPCome at me Bro

Break me now

I’m in printer

AES

3

WORRYANXIETY

NERVOUSFEAR

STRESS

STRESS

My PreciousMy Preciouss

My PreciousssMy Precioussss

My Precioussssssss

4

5

STEP 2

Alignment(horizontal/vertical)

Compression

Principal Component Analysis

Linear Discrimination Analysis

Frequency domain

STEP 1

Visual inspection

PC

Oscilloscope

Reader

Band Pass Filter

command

PowerEM

filtered signal

response

store signals

iteration

Ampli-fier

Measuring weak signal

STEP 3

……as alwaysKey doesn’t come out easily…

SNR? Power Model??

Countermeasure?

Any others??

GO Go GO!!!

I’m cool

Don’t care

Not going good…

WHY NOT??!!!!

THIS MIGHT BE IT!!!!

Let me see...

FFFFFFFFFFFFFFFFFFFFFF

8

Where is my key

Where is my peaks

9

At last ..4 month laterAfter many trials and errors…We finally found ‘the KEY’ at last..

10

Pre-processing

Distinguisher

Power Model

Enough Trace

11

Pre-processing

Distinguisher

Power Model

Enough Trace

King of

Mental

Most important thing is...

Thank you