def calculate_stabilities(self, instance, challenge_prng):
"""
Calculate the stability for random chosen challenges.
:param instance: SimulationMajorityLTFArray
A simulation of a Majority Vote Arbiter PUF.
:param challenge_prng: RandomState
Pseudo-random number generator which is used to generate challenges.
"""
challenges = np.array(
list(
tools.random_inputs(self.n,
self.N,
random_instance=challenge_prng)))
eval_array = np.zeros(len(challenges))
# Evaluation of the PUF in order to measure the stability
for i in range(self.iterations):
eval_array = eval_array + instance.eval(challenges)
# Calculation of the stability for every challenge
stab_array = (np.abs(eval_array) + self.iterations) / (2 *
self.iterations)
# Number which counts the satisfying challenges
num_goal_fulfilled = 0
# Check of the desired_stability
for i in range(self.N):
if stab_array[i] >= self.desired_stability:
num_goal_fulfilled += 1
# Relative frequency
self.overall_stab = num_goal_fulfilled / self.N
def test_transformations_combiner(self):
"""
This test checks all combinations of transformations and combiners for SimulationMajorityLTFArray to run.
"""
noise_prng = RandomState(seed=0xC0FFEE)
weight_prng1 = RandomState(seed=0xBADA55)
crp_count = 16 # number of random inputs per test set
n = 64
k = 2
mu = 0
sigma = 1
vote_count = 1
weight_array = LTFArray.normal_weights(n, k, mu, sigma, weight_prng1)
inputs = tools.random_inputs(
n, crp_count, random_instance=RandomState(seed=0xDEADDA7A))
combiners = get_functions_with_prefix('combiner_',
SimulationMajorityLTFArray)
transformations = get_functions_with_prefix(
'transform_', SimulationMajorityLTFArray)
for transformation in transformations:
for combiner in combiners:
mv_noisy_ltf_array = SimulationMajorityLTFArray(
weight_array=weight_array,
transform=transformation,
combiner=combiner,
sigma_noise=1,
random_instance_noise=noise_prng,
vote_count=vote_count,
)
mv_noisy_ltf_array.eval(inputs)
def run(self):
inputs = random_inputs(self.parameters.n, self.parameters.N,
RandomState(self.parameters.seed))
self.responses = self.instance.val(inputs)
self.uniqueness = zeros(shape=(self.parameters.k, self.parameters.k))
for (idx1, i1), (idx2, i2) in combinations(
enumerate(self.individual_instances), 2):
self.uniqueness[idx1,
idx2] = average(i1.eval(inputs) * i2.eval(inputs))
def test_majority_voting(self):
"""This method is used to test if majority vote works.
The first test checks for unequal PUF responses with a LTFArray without noise and a SimulationMajorityLTFArray
instance with noise. The second test checks if majority voting works and the instance with and without noise
generate equal resonses.
"""
weight_prng1 = RandomState(seed=0xBADA55)
noise_prng = RandomState(seed=0xC0FFEE)
crp_count = 16 # number of random inputs per test set
n = 8
k = 16
mu = 0
sigma = 1
vote_count = 1
weight_array = LTFArray.normal_weights(n, k, mu, sigma, weight_prng1)
mv_noisy_ltf_array = SimulationMajorityLTFArray(
weight_array=weight_array,
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
sigma_noise=1,
random_instance_noise=noise_prng,
vote_count=vote_count,
)
ltf_array = LTFArray(weight_array=weight_array,
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor)
inputs = tools.random_inputs(
n, crp_count, random_instance=RandomState(seed=0xDEADDA7A))
ltf_array_result = ltf_array.eval(inputs)
mv_noisy_ltf_array_result = mv_noisy_ltf_array.eval(inputs)
# These test checks if the output is different because of noise
self.assertFalse(
array_equal(ltf_array_result, mv_noisy_ltf_array_result),
'These arrays must be different')
# reset pseudo random number generator
noise_prng = RandomState(seed=0xC0FFEE)
# increase the vote_count in order to get equality
vote_count = 2845
mv_noisy_ltf_array = SimulationMajorityLTFArray(
weight_array=weight_array,
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
sigma_noise=1,
random_instance_noise=noise_prng,
vote_count=vote_count,
)
# This checks if the majority vote works
mv_noisy_ltf_array_result = mv_noisy_ltf_array.eval(inputs)
assert_array_equal(mv_noisy_ltf_array_result, ltf_array_result)
def test_chi_vectorized(self):
"""This function checks the return type of this function."""
n = 8
N = 2**int(n / 2)
s = random_input(n)
inputs = random_inputs(n, N)
chi_arr = chi_vectorized(s, inputs)
self.assertEqual(len(chi_arr), N,
'The array must contain {0} arrays.'.format(N))
self.assertEqual(chi_arr.dtype, BIT_TYPE,
'The array must be of type {0}'.format(BIT_TYPE))
def test_majority_voting(self):
weight_prng1 = RandomState(seed=0xBADA55)
noise_prng = RandomState(seed=0xC0FFEE)
crp_count = 16 # number of random inputs per test set
n = 8
k = 16
mu = 0
sigma = 1
vote_count = 1
weight_array = LTFArray.normal_weights(n, k, mu, sigma, weight_prng1)
mv_noisy_ltf_array = SimulationMajorityLTFArray(
weight_array=weight_array,
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
sigma_noise=1,
random_instance_noise=noise_prng,
vote_count=vote_count,
)
ltf_array = LTFArray(weight_array=weight_array,
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor)
inputs = array(
list(
tools.random_inputs(
n, crp_count,
random_instance=RandomState(seed=0xDEADDA7A))))
ltf_array_result = ltf_array.eval(inputs)
mv_noisy_ltf_array_result = mv_noisy_ltf_array.eval(inputs)
# These test checks if the output is different because of noise
self.assertFalse(
array_equal(ltf_array_result, mv_noisy_ltf_array_result),
'These arrays must be different')
# reset pseudo random number generator
noise_prng = RandomState(seed=0xC0FFEE)
# increase the vote_count in order to get equality
vote_count = 277
mv_noisy_ltf_array = SimulationMajorityLTFArray(
weight_array=weight_array,
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
sigma_noise=1,
random_instance_noise=noise_prng,
vote_count=vote_count,
)
# This checks if the majority vote works
mv_noisy_ltf_array_result = mv_noisy_ltf_array.eval(inputs)
assert_array_equal(mv_noisy_ltf_array_result, ltf_array_result)
def test_poly_mult_div(self):
"""This method checks the shape and type of two dimensional arrays."""
n = 8
k = 2
N = 2**int(n / 2)
challenges_11 = random_inputs(n, N)
challenges_01 = array(
[transform_challenge_11_to_01(c) for c in challenges_11],
dtype=BIT_TYPE)
irreducible_polynomial = array([1, 0, 1, 0, 0, 1, 1, 0, 1],
dtype=BIT_TYPE)
poly_mult_div(challenges_01, irreducible_polynomial, k)
self.check_multi_dimensional_array(challenges_01, N, n, BIT_TYPE)
def test_ltf_eval(self):
"""
Test ltf_eval for correct evaluation of LTFs.
"""
weight_prng_1 = RandomState(seed=0xBADA55)
weight_prng_2 = RandomState(seed=0xBADA55)
noise_prng_1 = RandomState(seed=0xC0FFEE)
noise_prng_2 = RandomState(seed=0xC0FFEE)
N = 100 # number of random inputs per test set
for test_parameters in self.test_set:
n = test_parameters[0]
k = test_parameters[1]
mu = test_parameters[2]
sigma = test_parameters[3]
transformed_inputs = LTFArray.transform_id(
tools.random_inputs(
n, N, random_instance=RandomState(seed=0xBAADA555)), k)
ltf_array = LTFArray(
weight_array=LTFArray.normal_weights(n, k, mu, sigma,
weight_prng_1),
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
)
noisy_ltf_array = NoisyLTFArray(
weight_array=LTFArray.normal_weights(n, k, mu, sigma,
weight_prng_2),
# weight_prng_2 was seeded identically to weight_prng_1
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
sigma_noise=1,
random_instance=noise_prng_1,
)
evaled_ltf_array = ltf_array.ltf_eval(transformed_inputs)
assert_array_equal(
around(evaled_ltf_array + noise_prng_2.normal(
loc=0, scale=1, size=(len(evaled_ltf_array), k)),
decimals=10),
around(noisy_ltf_array.ltf_eval(transformed_inputs),
decimals=10))
def test_ltf_eval(self):
"""
Test ltf_eval for correct evaluation of LTFs.
"""
N = 100 # number of random inputs per test set
def ltf_eval_slow(challenge, weights):
"""
evaluate a single challenge with a single ltf specified by weights
"""
assert len(challenge) == len(weights) - 1
return dot(challenge,
weights[:n]) + weights[n] # weights[n] is the bias
for test_parameters in self.test_set:
n = test_parameters[0]
k = test_parameters[1]
mu = test_parameters[2]
sigma = test_parameters[3]
inputs = tools.random_inputs(n,
N,
random_instance=RandomState(0xA1))
ltf_array = LTFArray(
weight_array=LTFArray.normal_weights(n, k, mu, sigma),
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
)
fast_evaluation_result = around(ltf_array.ltf_eval(
LTFArray.transform_id(inputs, k)),
decimals=8)
slow_evaluation_result = []
for challenge in inputs:
slow_evaluation_result.append([
ltf_eval_slow(challenge, ltf_array.weight_array[l])
for l in range(k)
])
slow_evaluation_result = around(slow_evaluation_result, decimals=8)
self.assertTupleEqual(shape(slow_evaluation_result), (N, k))
self.assertTupleEqual(shape(fast_evaluation_result), (N, k))
assert_array_equal(slow_evaluation_result, fast_evaluation_result)
def test_random_inputs(self):
"""This checks the shape and type of the returned multidimensional array."""
n = 8
N = 2**(int(n / 2))
rand_arrays = random_inputs(n, N)
self.check_multi_dimensional_array(rand_arrays, N, n, BIT_TYPE)
def run(self):
self.responses = self.instance.eval(
random_inputs(self.parameters.n, self.parameters.N,
RandomState(self.parameters.seed)))
