def train(challenges, responses, t_pairs):
try:
with open('weights.txt', 'rb') as f:
weights = np.load(f)
except:
print("[*] ENOWEIGHTS")
# create instance frome same weights for accuracy calculation
instance = LTFArray(
weight_array=weights,
transform=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
# train model from obtained CRPs
training_set = tools.ChallengeResponseSet(challenges, responses)
lr_learner = LogisticRegression(
t_set=training_set,
n=48,
k=4,
transformation=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
# learn and test the model
model = lr_learner.learn()
accuracy = 1 - tools.approx_dist(instance, model, 10000)
print('Learned a 48-bit 4-xor XOR Arbiter PUF from {} CRPs with accuracy {}'.format(t_pairs, accuracy))
return model
def pipeline(N):
instance = LTFArray(
weight_array=LTFArray.normal_weights(n=64, k=2),
transform=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor
)
train_set = tools.TrainingSet(instance=instance, N=N)
train_size = int(len(train_set.challenges) * 0.95)
val_set = train_set.subset(slice(train_size, None))
train_set = train_set.subset(slice(None, train_size))
lr_learner = LogisticRegression(
t_set=train_set,
n=64,
k=2,
transformation=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
model = lr_learner.learn()
val_set_predicted_responses = model.eval(val_set.challenges)
accuracy = accuracy_score(val_set_predicted_responses, val_set.responses)
return accuracy
def test_learn_ip_mod2(self):
""""
Stupid test which gains code coverage
"""
instance_prng = RandomState(seed=TestLogisticRegression.seed_instance)
model_prng = RandomState(seed=TestLogisticRegression.seed_model)
instance = LTFArray(
weight_array=LTFArray.normal_weights(
TestLogisticRegression.n,
TestLogisticRegression.k,
random_instance=instance_prng),
transform=LTFArray.transform_id,
combiner=LTFArray.combiner_ip_mod2,
)
lr_learner = LogisticRegression(
TrainingSet(instance=instance, N=TestLogisticRegression.N),
TestLogisticRegression.n,
TestLogisticRegression.k,
transformation=LTFArray.transform_id,
combiner=LTFArray.combiner_xor,
weights_prng=model_prng,
)
lr_learner.learn()
def main():
"""
Run an example how to use pypuf.
Developers Notice: Changes here need to be mirrored to README!
"""
# create a simulation with random (Gaussian) weights
# for 64-bit 4-XOR
instance = LTFArray(
weight_array=LTFArray.normal_weights(n=64, k=2),
transform=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
# create the learner
lr_learner = LogisticRegression(
t_set=tools.TrainingSet(instance=instance, N=12000),
n=64,
k=2,
transformation=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
# learn and test the model
model = lr_learner.learn()
accuracy = 1 - tools.approx_dist(instance, model, 10000)
# output the result
print('Learned a 64bit 2-xor XOR Arbiter PUF from 12000 CRPs with accuracy %f' % accuracy)
def prepare(self):
"""
Initializes the instance, the training set and the learner to then run the logistic regression
with the given parameters.
"""
self.instance = LTFArray(
weight_array=LTFArray.normal_weights(
self.parameters.n,
self.parameters.k,
random_instance=RandomState(
seed=self.parameters.seed_instance)),
transform=self.parameters.transformation,
combiner=self.parameters.combiner,
)
self.learner = LogisticRegression(
tools.TrainingSet(instance=self.instance,
N=self.parameters.N,
random_instance=RandomState(
self.parameters.seed_challenge)),
self.parameters.n,
self.parameters.k,
transformation=self.instance.transform,
combiner=self.instance.combiner,
weights_prng=RandomState(seed=self.parameters.seed_model),
logger=self.progress_logger,
minibatch_size=self.parameters.mini_batch_size,
convergance_decimals=self.parameters.convergence_decimals or 2,
shuffle=self.parameters.shuffle,
)
def prepare(self):
super().prepare()
self.learner = LogisticRegression(
t_set=TrainingSet(instance=self.ltf_array, N=self.parameters.N),
n=self.parameters.n,
k=self.parameters.k,
transformation=self.ltf_array.transform,
combiner=self.ltf_array.combiner,
convergence_decimals=100, # never converge
iteration_limit=20,
)
def main():
"""
Learns and evaluates a PUF.
"""
parser = argparse.ArgumentParser()
parser.add_argument('n', type=uint, help='challenge bits')
parser.add_argument('k', type=uint, help='number of arbiter chains')
parser.add_argument('num_tr',
type=uint,
help='number of CRPs to use for training')
parser.add_argument('num_te',
type=uint,
help='number of CRPs to use for testing')
parser.add_argument('file', type=str, help='file to read CRPs from')
parser.add_argument('-1',
'--11-notation',
dest='in_11_notation',
action='store_true',
default=False,
help='file is in -1,1 notation (default is 0,1)')
args = parser.parse_args()
# read pairs from file
training_set = tools.parse_file(args.file, args.n, 1, args.num_tr,
args.in_11_notation)
testing_set = tools.parse_file(args.file, args.n, args.num_tr + 1,
args.num_te, args.in_11_notation)
# create the learner
lr_learner = LogisticRegression(
t_set=training_set,
n=args.n,
k=args.k,
transformation=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
# learn and test the model
model = lr_learner.learn()
accuracy = 1 - tools.approx_dist_nonrandom(model, testing_set)
# output the result
print(
'Learned a {}-bit {}-xor XOR Arbiter PUF from {} CRPs with accuracy {}'
.format(args.n, args.k, args.num_tr, accuracy))
def run(self):
"""
Initializes the instance, the training set and the learner to then run the logistic regression
with the given parameters.
"""
# TODO input transformation is computed twice. Add a shortcut to recycle results from the first computation
self.instance = LTFArray(
weight_array=LTFArray.normal_weights(self.n, self.k, random_instance=self.instance_prng),
transform=self.transformation,
combiner=self.combiner,
)
self.learner = LogisticRegression(
tools.TrainingSet(instance=self.instance, N=self.N, random_instance=self.challenge_prng),
self.n,
self.k,
transformation=self.transformation,
combiner=self.combiner,
weights_prng=self.model_prng,
logger=self.progress_logger,
)
self.model = self.learner.learn()
class LRBenchmarkExperiment(LTFBenchmarkExperiment):
"""
Measures the time the logistic regression learner takes to learn a target.
"""
def __init__(self, progress_log_prefix, parameters):
super().__init__(progress_log_prefix, parameters)
self.learner = None
def prepare(self):
super().prepare()
self.learner = LogisticRegression(
t_set=TrainingSet(instance=self.ltf_array, N=self.parameters.N),
n=self.parameters.n,
k=self.parameters.k,
transformation=self.ltf_array.transform,
combiner=self.ltf_array.combiner,
convergence_decimals=100, # never converge
iteration_limit=20,
)
def run(self):
self.learner.learn()
def train():
instance = LTFArray(
weight_array=LTFArray.normal_weights(n=48, k=4),
transform=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
N = 18000
# learn and test the model
lr_learner = LogisticRegression(
t_set=tools.TrainingSet(instance=instance, N=N),
n=48,
k=4,
transformation=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
model = lr_learner.learn()
accuracy = 1 - tools.approx_dist(instance, model, 10000)
print(
'Learned a 48bit 4-xor XOR Arbiter PUF from %d CRPs with accuracy %f' %
(N, accuracy))
class CorrelationAttack(Learner):
"""
Learn an LTF-Array that uses the transform_lightweight_secure.
This Attack uses Logistic Regression (LR) to learn an initial model and subsequently exploits the correlation
between the weight arrays to restart the LR learner on a permuted model. This leads to a
faster retrieval of high-accuracy models than pure LR.
"""
OPTIMIZATION_ACCURACY_LOWER_BOUND = .65
OPTIMIZATION_ACCURACY_UPPER_BOUND = .95
OPTIMIZATION_ACCURACY_GOAL = .98
def __init__(self,
n,
k,
training_set,
validation_set,
weights_mu=0,
weights_sigma=1,
weights_prng=RandomState(),
lr_iteration_limit=1000,
mini_batch_size=0,
convergence_decimals=2,
shuffle=False,
logger=None):
"""
Initialize a Correlation Attack Learner for the specified LTF Array which uses transform_lightweight_secure.
:param n: Input length
:param k: Number of parallel LTFs in the LTF Array
:param training_set: The training set, i.e. a data structure containing challenge response pairs
:param validation_set: The validation set, i.e. a data structure containing challenge response pairs. Used for
approximating accuracies of permuted models (can be smaller e.g. 0.1*training_set_size)
:param weights_mu: mean of the Gaussian that is used to choose the initial model
:param weights_sigma: standard deviation of the Gaussian that is used to choose the initial model
:param weights_prng: PRNG to draw the initial model from. Defaults to fresh `numpy.random.RandomState` instance.
:param lr_iteration_limit: Iteration limit for a single LR learner run
:param logger: logging.Logger
Logger which is used to log detailed information of learn iterations.
"""
self.n = n
self.k = k
self.validation_set_efba = ChallengeResponseSet(
challenges=LTFArray.efba_bit(
LTFArray.transform_lightweight_secure(
validation_set.challenges, k)),
responses=validation_set.responses)
self.logger = logger
self.lr_learner = LogisticRegression(
t_set=training_set,
n=n,
k=k,
transformation=LTFArray.transform_lightweight_secure,
combiner=LTFArray.combiner_xor,
weights_mu=weights_mu,
weights_sigma=weights_sigma,
weights_prng=weights_prng,
logger=logger,
iteration_limit=lr_iteration_limit,
minibatch_size=mini_batch_size,
convergence_decimals=convergence_decimals,
shuffle=shuffle)
self.initial_accuracy = .5
self.initial_lr_iterations = 0
self.initial_model = None
self.total_lr_iterations = 0
self.best_permutation_iteration = 0
self.total_permutation_iterations = 0
self.best_permutation = None
self.best_accuracy = None
assert n in (
64, 128
), 'Correlation attack for %i bit is currently not supported.' % n
assert validation_set.N >= 1000, 'Validation set should contain at least 1000 challenges.'
self.correlation_permutations = loadmat(
'data/correlation_permutations_lightweight_secure_%i_10.mat' %
n)['shiftOverviewData'][:, :, 0].astype('int64')
def learn(self):
"""
Compute a model according to the given LTF Array parameters and training set.
Note that this function can take long to return.
:return: pypuf.simulation.arbiter_based.LTFArray
The computed model.
"""
self.initial_model = initial_model = self.lr_learner.learn()
self.logger.debug('initial weights for corr attack:')
self.logger.debug(','.join(
map(str, initial_model.weight_array.flatten())))
self.initial_accuracy = self.approx_accuracy(
initial_model, self.validation_set_efba.block_subset(0, 2))
self.initial_lr_iterations = self.lr_learner.iteration_count
self.total_lr_iterations = self.initial_lr_iterations
initial_updater = self.lr_learner.updater
self.best_accuracy = self.initial_accuracy
self.logger.debug('Initial accuracy is %.4f' % self.initial_accuracy)
if self.initial_accuracy < self.OPTIMIZATION_ACCURACY_LOWER_BOUND:
self.logger.debug('initial learning below threshold, aborting')
return initial_model
if self.initial_accuracy > self.OPTIMIZATION_ACCURACY_GOAL:
self.logger.debug('initial learning successful, aborting')
return initial_model
# Try all permutations with high initial accuracy and see if any of them lead to a good final result
high_accuracy_permutations = self.find_high_accuracy_weight_permutations(
initial_model.weight_array,
# allow some accuracy loss by permuting
# the higher the initial accuracy, the higher the loss we allow
# result will never be below 0.925
1.2 * self.best_accuracy - .2)
best_model = initial_model
self.logger.debug('Trying %i permuted weights.' %
len(high_accuracy_permutations))
for (iteration, perm_data) in enumerate(high_accuracy_permutations):
self.total_permutation_iterations += 1
weights = self.adopt_weights(initial_model.weight_array,
perm_data.permutation)
self.lr_learner.updater = deepcopy(initial_updater)
self.lr_learner.updater.step_size *= 10
model = self.lr_learner.learn(init_weight_array=weights,
refresh_updater=False)
self.total_lr_iterations += self.lr_learner.iteration_count
accuracy = self.approx_accuracy(
model, self.validation_set_efba.block_subset(1, 2))
self.logger.debug(
'With permutation no %d=%s, after restarting the learning we achieved accuracy %.4f -> %.4f!'
% (iteration, perm_data.permutation, perm_data.accuracy,
accuracy))
if accuracy > 0.1 + 0.9 * self.initial_accuracy \
and accuracy > self.best_accuracy:
# demand some "substantial" improvement of accuracy
# what substantial means becomes weaker as we approach
# perfect accuracy
best_model = model
self.best_accuracy = accuracy
self.best_permutation_iteration = iteration + 1
self.best_permutation = perm_data.permutation
else:
self.logger.debug(
'Learning after permuting lead to accuracy %.2f, no improvement :-('
% accuracy)
if accuracy > self.OPTIMIZATION_ACCURACY_GOAL:
self.logger.debug(
'Found a model with accuracy better than %.2f. Terminating'
% self.OPTIMIZATION_ACCURACY_GOAL)
return model
self.logger.debug(
'After trying all permutations, we found a model with acc. %.2f.' %
self.best_accuracy)
return best_model
def find_high_accuracy_weight_permutations(self, weights, threshold):
"""
Gives permutations for the weight-array resulting in the highest model accuracies.
:param weights: The original weight-array
:param threshold: Minimum accuracy to consider
:return: The 5k permutations with the highest accuracy
"""
high_accuracy_permutations = []
adopted_instance = LTFArray(
weight_array=zeros((self.k, self.n)),
transform=LTFArray.transform_lightweight_secure,
combiner=LTFArray.combiner_xor)
for permutation in list(permutations(range(self.k)))[1:]:
adopted_instance.weight_array = self.adopt_weights(
weights, permutation)
accuracy = self.approx_accuracy(adopted_instance)
self.logger.debug('For permutation %s, we have accuracy %.4f' %
(permutation, accuracy))
if accuracy >= threshold:
high_accuracy_permutations.append(
PermData(permutation, accuracy))
high_accuracy_permutations.sort(key=lambda x: -x.accuracy)
return high_accuracy_permutations[:5 * self.k]
def approx_accuracy(self, instance, efba_set=None):
"""
Approximate the accuracy of the instance on the given set.
:param instance: pypuf.simulation.arbiter_based.LTFArray
:param efba_set: A challenge-response-set containing efba sub-challenges (default: self.validation_set_efba)
:return: Accuracy of the instance
"""
if efba_set is None:
efba_set = self.validation_set_efba
size = efba_set.N
responses = sign(
instance.combiner(instance.core_eval(efba_set.challenges)))
return count_nonzero(responses == efba_set.responses) / size
def adopt_weights(self, weights, permutation):
"""
Adopts the weights with the given permutation exploiting the correlations of the lightweight-secure transform.
:param weights: A weight-array of an LTFArray
:param permutation: Permutation as returned from itertools.permutations
:return: Permuted weight-array
"""
adopted_weights = empty(weights.shape)
for l in range(self.k):
adopted_weights[permutation[l], :] = \
roll(weights[l, :], self.correlation_permutations[l, permutation[l]])
return adopted_weights
)
train_set = tools.TrainingSet(instance=instance, N=15000)
val_set = train_set.subset(slice(10000, None))
train_set = train_set.subset(slice(None, 10000))
challenges, responses = train_set.challenges, train_set.responses
print(challenges.shape, responses.shape)
from pypuf.learner.regression.logistic_regression import LogisticRegression
lr_learner = LogisticRegression(
t_set=train_set,
n=64,
k=2,
transformation=LTFArray.transform_atf,
combiner=LTFArray.combiner_xor,
)
model = lr_learner.learn()
val_set_predicted_responses = model.eval(val_set.challenges)
acc = accuracy_score(val_set_predicted_responses, val_set.responses)
print('accuracy: ', acc)
from pypuf.learner.other import Boosting
boosting_learner = Boosting(
t_set=train_set,
class ExperimentLogisticRegression(Experiment):
"""
This Experiment uses the logistic regression learner on an LTFArray PUF simulation.
"""
def __init__(self, progress_log_prefix, parameters):
progress_log_name = None if progress_log_prefix is None else '%s.0x%x_0x%x_0_%i_%i_%i_%s_%s' % (
progress_log_prefix,
parameters.seed_model,
parameters.seed_instance,
parameters.n,
parameters.k,
parameters.N,
parameters.transformation,
parameters.combiner,
)
super().__init__(progress_log_name, parameters)
self.instance = None
self.learner = None
self.model = None
def prepare(self):
"""
Initializes the instance, the training set and the learner to then run the logistic regression
with the given parameters.
"""
self.instance = LTFArray(
weight_array=LTFArray.normal_weights(
self.parameters.n,
self.parameters.k,
random_instance=RandomState(
seed=self.parameters.seed_instance)),
transform=self.parameters.transformation,
combiner=self.parameters.combiner,
)
self.learner = LogisticRegression(
tools.TrainingSet(instance=self.instance,
N=self.parameters.N,
random_instance=RandomState(
self.parameters.seed_challenge)),
self.parameters.n,
self.parameters.k,
transformation=self.instance.transform,
combiner=self.instance.combiner,
weights_prng=RandomState(seed=self.parameters.seed_model),
logger=self.progress_logger,
minibatch_size=self.parameters.mini_batch_size,
convergance_decimals=self.parameters.convergence_decimals or 2,
shuffle=self.parameters.shuffle,
)
def run(self):
"""
Runs the learner
"""
self.model = self.learner.learn()
def analyze(self):
"""
Analyzes the learned result.
"""
assert self.model is not None
accuracy = 1.0 - tools.approx_dist(
self.instance,
self.model,
min(10000, 2**self.parameters.n),
random_instance=RandomState(self.parameters.seed_distance),
)
return Result(
experiment_id=self.id,
pid=getpid(),
iteration_count=self.learner.iteration_count,
epoch_count=self.learner.epoch_count,
gradient_step_count=self.learner.gradient_step_count,
measured_time=self.measured_time,
accuracy=accuracy,
model=self.model.weight_array.flatten() /
norm(self.model.weight_array.flatten()),
)
if algorithm==2:
learner = PolytopeAlgorithm(
instance,
tools.TrainingSet(instance=instance, N=N),
n,
k,
transformation=transformation,
combiner=combiner,
weights_prng=model_prng,
)
else:
learner = LogisticRegression(
tools.TrainingSet(instance=instance, N=N),
n,
k,
transformation=transformation,
combiner=combiner,
weights_prng=model_prng,
)
i = 0
dist = 1
while i < restarts and 1 - dist < convergence:
stderr.write('\r%5i/%5i ' % (i+1, restarts if restarts < float('inf') else 0))
start = time.time()
model = learner.learn()
end = time.time()
training_times = append(training_times, end - start)
dist = tools.approx_dist(instance, model, min(10000, 2 ** n))
accuracy = append(accuracy, 1 - dist)
def __init__(self,
n,
k,
training_set,
validation_set,
weights_mu=0,
weights_sigma=1,
weights_prng=RandomState(),
lr_iteration_limit=1000,
mini_batch_size=0,
convergence_decimals=2,
shuffle=False,
logger=None):
"""
Initialize a Correlation Attack Learner for the specified LTF Array which uses transform_lightweight_secure.
:param n: Input length
:param k: Number of parallel LTFs in the LTF Array
:param training_set: The training set, i.e. a data structure containing challenge response pairs
:param validation_set: The validation set, i.e. a data structure containing challenge response pairs. Used for
approximating accuracies of permuted models (can be smaller e.g. 0.1*training_set_size)
:param weights_mu: mean of the Gaussian that is used to choose the initial model
:param weights_sigma: standard deviation of the Gaussian that is used to choose the initial model
:param weights_prng: PRNG to draw the initial model from. Defaults to fresh `numpy.random.RandomState` instance.
:param lr_iteration_limit: Iteration limit for a single LR learner run
:param logger: logging.Logger
Logger which is used to log detailed information of learn iterations.
"""
self.n = n
self.k = k
self.validation_set_efba = ChallengeResponseSet(
challenges=LTFArray.efba_bit(
LTFArray.transform_lightweight_secure(
validation_set.challenges, k)),
responses=validation_set.responses)
self.logger = logger
self.lr_learner = LogisticRegression(
t_set=training_set,
n=n,
k=k,
transformation=LTFArray.transform_lightweight_secure,
combiner=LTFArray.combiner_xor,
weights_mu=weights_mu,
weights_sigma=weights_sigma,
weights_prng=weights_prng,
logger=logger,
iteration_limit=lr_iteration_limit,
minibatch_size=mini_batch_size,
convergence_decimals=convergence_decimals,
shuffle=shuffle)
self.initial_accuracy = .5
self.initial_lr_iterations = 0
self.initial_model = None
self.total_lr_iterations = 0
self.best_permutation_iteration = 0
self.total_permutation_iterations = 0
self.best_permutation = None
self.best_accuracy = None
assert n in (
64, 128
), 'Correlation attack for %i bit is currently not supported.' % n
assert validation_set.N >= 1000, 'Validation set should contain at least 1000 challenges.'
self.correlation_permutations = loadmat(
'data/correlation_permutations_lightweight_secure_%i_10.mat' %
n)['shiftOverviewData'][:, :, 0].astype('int64')
class ExperimentLogisticRegression(Experiment):
"""
This Experiment uses the logistic regression learner on an LTFArray PUF simulation.
"""
def __init__(self, log_name, n, k, N, seed_instance, seed_model,
transformation, combiner):
super().__init__(log_name='%s.0x%x_0x%x_0_%i_%i_%i_%s_%s' % (
log_name,
seed_model,
seed_instance,
n,
k,
N,
transformation.__name__,
combiner.__name__,
), )
self.n = n
self.k = k
self.N = N
self.seed_instance = seed_instance
self.instance_prng = RandomState(seed=self.seed_instance)
self.seed_model = seed_model
self.model_prng = RandomState(seed=self.seed_model)
self.combiner = combiner
self.transformation = transformation
self.instance = None
self.learner = None
self.model = None
def run(self):
"""
Initializes the instance, the training set and the learner to then run the logistic regression
with the given parameters.
"""
# TODO input transformation is computed twice. Add a shortcut to recycle results from the first computation
self.instance = LTFArray(
weight_array=LTFArray.normal_weights(
self.n, self.k, random_instance=self.instance_prng),
transform=self.transformation,
combiner=self.combiner,
)
self.learner = LogisticRegression(
tools.TrainingSet(instance=self.instance, N=self.N),
self.n,
self.k,
transformation=self.transformation,
combiner=self.combiner,
weights_prng=self.model_prng,
logger=self.progress_logger,
)
self.model = self.learner.learn()
def analyze(self):
"""
Analyzes the learned result.
"""
assert self.model is not None
self.result_logger.info(
# seed_instance seed_model i n k N trans comb iter time accuracy model values
'0x%x\t'
'0x%x\t'
'%i\t'
'%i\t'
'%i\t'
'%i\t'
'%s\t'
'%s\t'
'%i\t'
'%f\t'
'%f\t'
'%s' % (
self.seed_instance,
self.seed_model,
0, # restart count, kept for compatibility to old log files
self.n,
self.k,
self.N,
self.transformation.__name__,
self.combiner.__name__,
self.learner.iteration_count,
self.measured_time,
1.0 - tools.approx_dist(self.instance, self.model,
min(10000, 2**self.n)),
','.join(
map(
str,
self.model.weight_array.flatten() /
norm(self.model.weight_array.flatten())))))
class ExperimentLogisticRegression(Experiment):
"""
This Experiment uses the logistic regression learner on an LTFArray PUF simulation.
"""
def __init__(
self, log_name, n, k, N, seed_instance, seed_model, transformation, combiner, seed_challenge=0x5A551,
seed_chl_distance=0xB055,
):
"""
:param log_name: string
Prefix of the path or name of the experiment log file.
:param n: int
Number of stages of the PUF
:param k: int
Number different LTFArrays
:param N: int
Number of challenges which are generated in order to learn the PUF simulation.
:param seed_instance: int
The seed which is used to initialize the pseudo-random number generator
which is used to generate the stage weights for the arbiter PUF simulation.
:param seed_model: int
The seed which is used to initialize the pseudo-random number generator
which is used to generate the stage weights for the learner arbiter PUF simulation.
:param transformation: A function: array of int with shape(N,k,n), int number of PUFs k -> shape(N,k,n)
The function transforms input challenges in order to increase resistance against attacks.
:param combiner: A function: array of int with shape(N,k,n) -> array of in with shape(N)
The functions combines the outputs of k PUFs to one bit results,
in oder to increase resistance against attacks.
:param seed_challenge: int default is 0x5A551
The seed which is used to initialize the pseudo-random number generator
which is used to draft challenges for the TrainingSet.
:param seed_chl_distance: int default is 0xB055
The seed which is used to initialize the pseudo-random number generator
which is used to draft challenges for the accuracy calculation.
"""
super().__init__(
log_name='%s.0x%x_0x%x_0_%i_%i_%i_%s_%s' % (
log_name,
seed_model,
seed_instance,
n,
k,
N,
transformation.__name__,
combiner.__name__,
),
)
self.n = n
self.k = k
self.N = N
self.seed_instance = seed_instance
self.instance_prng = RandomState(seed=self.seed_instance)
self.seed_model = seed_model
self.model_prng = RandomState(seed=self.seed_model)
self.combiner = combiner
self.transformation = transformation
self.seed_challenge = seed_challenge
self.challenge_prng = RandomState(self.seed_challenge)
self.seed_chl_distance = seed_chl_distance
self.distance_prng = RandomState(self.seed_chl_distance)
self.instance = None
self.learner = None
self.model = None
def run(self):
"""
Initializes the instance, the training set and the learner to then run the logistic regression
with the given parameters.
"""
# TODO input transformation is computed twice. Add a shortcut to recycle results from the first computation
self.instance = LTFArray(
weight_array=LTFArray.normal_weights(self.n, self.k, random_instance=self.instance_prng),
transform=self.transformation,
combiner=self.combiner,
)
self.learner = LogisticRegression(
tools.TrainingSet(instance=self.instance, N=self.N, random_instance=self.challenge_prng),
self.n,
self.k,
transformation=self.transformation,
combiner=self.combiner,
weights_prng=self.model_prng,
logger=self.progress_logger,
)
self.model = self.learner.learn()
def analyze(self):
"""
Analyzes the learned result.
"""
assert self.model is not None
self.result_logger.info(
# seed_instance seed_model i n k N trans comb iter time accuracy model values
'0x%x\t' '0x%x\t' '%i\t' '%i\t' '%i\t' '%i\t' '%s\t' '%s\t' '%i\t' '%f\t' '%f\t' '%s',
self.seed_instance,
self.seed_model,
0, # restart count, kept for compatibility to old log files
self.n,
self.k,
self.N,
self.transformation.__name__,
self.combiner.__name__,
self.learner.iteration_count,
self.measured_time,
1.0 - tools.approx_dist(
self.instance,
self.model,
min(10000, 2 ** self.n),
random_instance=self.distance_prng,
),
','.join(map(str, self.model.weight_array.flatten() / norm(self.model.weight_array.flatten())))
)
def main(args):
if len(args) != 10:
stderr.write('LTF Array Simulator and Logistic Regression Learner\n')
stderr.write('Usage:\n')
stderr.write(
'sim_learn.py n k transformation combiner N restarts seed_instance seed_model\n'
)
stderr.write(' n: number of bits per Arbiter chain\n')
stderr.write(' k: number of Arbiter chains\n')
stderr.write(
' transformation: used to transform input before it is used in LTFs\n'
)
stderr.write(' currently available:\n')
stderr.write(' - id -- does nothing at all\n')
stderr.write(
' - atf -- convert according to "natural" Arbiter chain\n'
)
stderr.write(' implementation\n')
stderr.write(
' - mm -- designed to achieve maximum PTF expansion length\n'
)
stderr.write(
' only implemented for k=2 and even n\n')
stderr.write(
' - lightweight_secure -- design by Majzoobi et al. 2008\n'
)
stderr.write(
' only implemented for even n\n'
)
stderr.write(
' - shift_lightweight_secure -- design like Majzoobi\n'
)
stderr.write(
' et al. 2008, but with the shift\n'
)
stderr.write(
' operation executed first\n'
)
stderr.write(
' only implemented for even n\n'
)
stderr.write(
' - soelter_lightweight_secure -- design like Majzoobi\n'
)
stderr.write(
' et al. 2008, but one bit different\n'
)
stderr.write(
' only implemented for even n\n'
)
stderr.write(
' - 1_n_bent -- one LTF gets "bent" input, the others id\n'
)
stderr.write(
' - 1_1_bent -- one bit gets "bent" input, the others id,\n'
)
stderr.write(
' this is proven to have maximum PTF\n'
)
stderr.write(' length for the model\n')
stderr.write(
' - polynomial -- challenges are interpreted as polynomials\n'
)
stderr.write(
' from GF(2^64). From the initial challenge c,\n'
)
stderr.write(
' the i-th Arbiter chain gets the coefficients \n'
)
stderr.write(
' of the polynomial c^(i+1) as challenge.\n'
)
stderr.write(
' For now only challenges with length n=64 are accepted.\n'
)
stderr.write(
' - permutation_atf -- for each Arbiter chain first a pseudorandom permutation \n'
)
stderr.write(
' is applied and thereafter the ATF transform.\n'
)
stderr.write(
' - random -- Each Arbiter chain gets a random challenge derived from the\n'
)
stderr.write(
' original challenge using a PRNG.\n')
stderr.write(
' combiner: used to combine the output bits to a single bit\n'
)
stderr.write(' currently available:\n')
stderr.write(
' - xor -- output the parity of all output bits\n'
)
stderr.write(
' - ip_mod2 -- output the inner product mod 2 of all output\n'
)
stderr.write(' bits (even n only)\n')
stderr.write(
' N: number of challenge response pairs in the training set\n'
)
stderr.write(
' restarts: number of repeated initializations the learner\n'
)
stderr.write(
' use float number x, 0<x<1 to repeat until given accuracy\n'
)
stderr.write(
' instances: number of repeated initializations the instance\n'
)
stderr.write(
' The number total learning attempts is restarts*instances.\n'
)
stderr.write(
' seed_instance: random seed used for LTF array instance\n')
stderr.write(
' seed_model: random seed used for the model in first learning attempt\n'
)
quit(1)
n = int(args[1])
k = int(args[2])
transformation_name = args[3]
combiner_name = args[4]
N = int(args[5])
if float(args[6]) < 1:
restarts = float('inf')
convergence = float(args[6])
else:
restarts = int(args[6])
convergence = 1.1
instances = int(args[7])
seed_instance = int(args[8], 16)
seed_model = int(args[9], 16)
# reproduce 'random' numbers and avoid interference with other random numbers drawn
instance_prng = RandomState(seed=seed_instance)
model_prng = RandomState(seed=seed_model)
transformation = None
combiner = None
try:
transformation = getattr(LTFArray,
'transform_%s' % transformation_name)
except AttributeError:
stderr.write(
'Transformation %s unknown or currently not implemented\n' %
transformation_name)
quit()
try:
combiner = getattr(LTFArray, 'combiner_%s' % combiner_name)
except AttributeError:
stderr.write('Combiner %s unknown or currently not implemented\n' %
combiner_name)
quit()
stderr.write(
'Learning %s-bit %s XOR Arbiter PUF with %s CRPs and %s restarts.\n\n'
% (n, k, N, restarts))
stderr.write('Using\n')
stderr.write(' transformation: %s\n' % transformation)
stderr.write(' combiner: %s\n' % combiner)
stderr.write(' instance random seed: 0x%x\n' % seed_instance)
stderr.write(' model random seed: 0x%x\n' % seed_model)
stderr.write('\n')
accuracy = array([])
training_times = array([])
iterations = array([])
for j in range(instances):
stderr.write('----------- Choosing new instance. ---------\n')
instance = LTFArray(
weight_array=LTFArray.normal_weights(
n, k, random_instance=instance_prng),
transform=transformation,
combiner=combiner,
)
lr_learner = LogisticRegression(
tools.TrainingSet(instance=instance, N=N),
n,
k,
transformation=transformation,
combiner=combiner,
weights_prng=model_prng,
)
i = 0
dist = 1
while i < restarts and 1 - dist < convergence:
stderr.write('\r%5i/%5i ' %
(i + 1, restarts if restarts < float('inf') else 0))
start = time.time()
model = lr_learner.learn()
end = time.time()
training_times = append(training_times, end - start)
dist = tools.approx_dist(instance, model, min(10000, 2**n))
accuracy = append(accuracy, 1 - dist)
iterations = append(iterations, lr_learner.iteration_count)
# output test result in machine-friendly format
# seed_ltf seed_model idx_restart n k N transformation combiner iteration_count time accuracy
stderr.write(' '.join([
'0x%x' % seed_instance,
'0x%x' % seed_model,
'%5d' % i,
'%3d' % n,
'%2d' % k,
'%6d' % N,
'%s' % transformation_name,
'%s' % combiner_name,
'%4d' % lr_learner.iteration_count,
'%9.3f' % (end - start),
'%1.5f' % (1 - dist),
]) + '\n')
#stderr.write('training time: % 5.3fs' % (end - start))
#stderr.write('min training distance: % 5.3f' % lr_learner.min_distance)
#stderr.write('test distance (1000 samples): % 5.3f\n' % dist)
i += 1
stderr.write('\r \r')
stderr.write('\n\n')
stderr.write('training times: %s\n' % training_times)
stderr.write('iterations: %s\n' % iterations)
stderr.write('test accuracy: %s\n' % accuracy)
stderr.write('\n\n')
stderr.write(
'min/avg/max training time : % 9.3fs /% 9.3fs /% 9.3fs\n' %
(amin(training_times), mean(training_times), amax(training_times)))
stderr.write('min/avg/max iteration count: % 9.3f /% 9.3f /% 9.3f \n' %
(amin(iterations), mean(iterations), amax(iterations)))
stderr.write('min/avg/max test accuracy : % 9.3f /% 9.3f /% 9.3f \n' %
(amin(accuracy), mean(accuracy), amax(accuracy)))
stderr.write('\n\n')
