chipwhisperer lite - cleveland state university · chipwhisperer lite open source tool for research...
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ChipWhisperer Lite
Open source tool for research on hardware attacks
• Side Channel Power Analysis
• Glitching Attacks
Essentially an oscilloscope attached to a target chip
Modeling Power Consumption
Every device requires power to run (static power)
Data moving through the device changes power consumption (dynamic power)
Dynamic Power – Current required to charge or discharge data lines
00110000 transitioning to 00100011
• 3 bits changed
Correlation Power Analysis
Force target device to encrypt many different things
Log traces of these different encryptions
Analyze these different traces and determine subkeys
BREAK ENCRYPTION!
Setting up target device
• Connect to Chipwhisper and set up target board
• Connect_cwlite _simpleserial
Setting up oscilloscope
• Connect to Chipwhisper and set up scope to capture traces
• Setup_cwlite_xmega_aes
CAPTURE TRACES!
• Settings on left
• Captured traces displayed on the right
Analyze Traces• attack_cpa
Attacking AES Encryption
Results table: first row (in white) is the “result key” from analysis.
Note this is the same key as used to generate the traces!
How’d it do that?
How AES works:• AES algorithm XORs the key and data
• Uses s-box defined lookup table to replace data
• S-box is public
and known
Breaking AES
Above equation is the relationship between a hypothetical guess for each XOR equation (both key and data to encrypt)
compared to the actual change in the trace
Apply hypothetical guesses
• Apply hypothetical guesses to each trace and see what matches
• Keep track of which hypothetical has best guess
• Percentage confidence is the [0,1] number below the results
Results Table (again)