WBC DFA IMPLEMENTATION

This repository contains a WBC DFA attack implementation.

What is DFA?

Differential fault analysis (DFA) is a type of side channel attack in the field of cryptography, specifically cryptanalysis. The principle is to induce faults—unexpected environmental conditions—into cryptographic implementations, to reveal their internal states.

Requirements

Python Dependencies

pip3 install -r requirements.txt

Traces

In order to perform a DFA attack, it's needed to provide some traces.

The first trace will be the correct output of the WBC (without a fault).
All the other traces will be the outputs of the WBC with faults (the more, the better).

Example of the traces:

17,35,D1,09,C2,36,C4,CF,B4,E7,48,7C,80,27,8C,71
17,35,D1,36,C2,36,BB,CF,B4,44,48,7C,51,27,8C,71
17,7B,D1,09,49,36,C4,CF,B4,E7,48,AC,80,27,45,71
17,35,D1,AA,C2,36,1B,CF,B4,10,48,7C,DC,27,8C,71

Every 4 bytes represents one column of the output.

Usage

Execute the dfa script with Python3 and specify the output file.

python3 dfa.py outputs_DFA.dat [limit] [-log]

[limit]: Specifies how many candidates are needed for the DFA (0 by default).
[-log]: Specifies if you want to write all the candidates inside a file.

Example

This example is performed using the outputs_DFA_AES128.dat file.

python3 dfa.py outputs_DFA.dat 100000 -log

The tool will do the next output:

[DFA] Trace file selected: outputs_DFA_AES128.dat.
[DFA] Candidates needed: 0.
[DFA] Logging enabled.
[DFA] Starting thread for target [(0, 0), (1, 3), (2, 2), (3, 1)].
[DFA] Starting thread for target [(0, 1), (1, 0), (2, 3), (3, 2)].
[DFA] Starting thread for target [(0, 2), (1, 1), (2, 0), (3, 3)].
[DFA] Starting thread for target [(0, 3), (1, 2), (2, 1), (3, 0)].
[DFA] SubKey10.
[['0x22' '0xf4' '0x32' '0xfa']
['0xf1' '0x79' '0x12' '0x8e']
['0xc' '0x86' '0x14' '0xe1']
['0x20' '0x12' '0x4' '0x20']]
[DFA] MasterKey.
[['0xca' '0xfe' '0xba' '0xbe']
['0xde' '0xad' '0xbe' '0xef']
['0xca' '0xfe' '0xba' '0xbe']
['0xde' '0xad' '0xbe' '0xef']]

The SubKey10 and MasterKey will be printed.

TODO

Finish CCA implementation.

Inspiration

A project inspired by:

Differential Fault Analysis on A.E.S.
People breaking WBC implementations.

jcalabres / WhiteboxCrypto