Hiding Class Reference

Class that implements 2 hiding techniques: dummy-ops & shuffling. More...

#include <hiding.h>

Collaboration diagram for Hiding:

Public Member Functions
	Hiding ()=default
	Construct a new Hiding object.
void	init ()
	Initialize AES hiding operations. More...
void	shuffleSBoxAccess (uint8_t indices[])
	Shuffle the S-Box access. More...
void	dummyOp ()
	Perform a dummy NOP operation a random number of times.

Private Member Functions
void	shuffleArray (uint8_t array[], const uint8_t size)
	Shuffle an array using the Fisher-Yates shuffle. More...

Private Attributes
uint8_t	mNumbersDummyOps [NUMBER_OPS] = {}
	Array of random numbers, which specify the number of dummy ops per round.
uint8_t	mNoOpCounter = 0
	Counter for the number of dummy ops per round.
RNG	mRNG
	Random number generator.

Static Private Attributes
static constexpr uint8_t	MAX_NUMBER_NO_OPS = 100
	The maximum number of NOPs per AES execution. It is important that this number stays the same for every AES execution.
static constexpr uint8_t	NUMBER_OPS = 40
	The number of operations before which the dummy ops are executed.
static uint8_t	DEFAULT_INV_SBOX_INDICES [STATE_BYTES]
	Array that contains values from 0 to 15.

Detailed Description

Class that implements 2 hiding techniques: dummy-ops & shuffling.

As a counter-measure against DPA attacks, hiding can be used to randomize the timing behaviour of the AES en-/decryption. This can be done by adding random dummy-ops or by randomly shuffling the S-Box access.

Authors

Philipp Karg (phili.nosp@m.pp.k.nosp@m.arg@t.nosp@m.um.d.nosp@m.e)

Date

04.07.2022

Copyright

Philipp Karg 2022

Member Function Documentation

init()

void Hiding::init

(

)

Initialize AES hiding operations.

1. Seed the RNG.
2. Init the dummy ops by creating an array of random numbers, w which will be the number of dummy ops per round. It is important that the total number of dummy ops stays the same for every AES execution.

shuffleArray()

void Hiding::shuffleArray ( uint8_t  array[], const uint8_t  size  )

private

Shuffle an array using the Fisher-Yates shuffle.

Parameters

[in,out]	array	(uint8_t []): Array to shuffle.
[in]	size	(const uint8_t): Size of the array.

shuffleSBoxAccess()

void Hiding::shuffleSBoxAccess

(

uint8_t

indices[]

)

Shuffle the S-Box access.

Randomize the S-Box access by shuffling the indices of the S-Box.

Parameters

[out]

indices

(uint8_t []): Array of indices of the S-Box.

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The documentation for this class was generated from the following file:

• hiding.h