def run(
self,
model: Model,
inputs: T,
criterion: Union[Misclassification, TargetedMisclassification, T],
*,
early_stop: Optional[float] = None,
**kwargs: Any,
) -> T:
raise_if_kwargs(kwargs)
x, restore_type = ep.astensor_(inputs)
criterion_ = get_criterion(criterion)
del inputs, criterion, kwargs
N = len(x)
if isinstance(criterion_, Misclassification):
targeted = False
classes = criterion_.labels
elif isinstance(criterion_, TargetedMisclassification):
targeted = True
classes = criterion_.target_classes
else:
raise ValueError("unsupported criterion")
if classes.shape != (N, ):
name = "target_classes" if targeted else "labels"
raise ValueError(
f"expected {name} to have shape ({N},), got {classes.shape}")
stepsize = 1.0
min_, max_ = model.bounds
def loss_fn(inputs: ep.Tensor,
labels: ep.Tensor) -> Tuple[ep.Tensor, ep.Tensor]:
logits = model(inputs)
sign = -1.0 if targeted else 1.0
loss = sign * ep.crossentropy(logits, labels).sum()
return loss, logits
grad_and_logits = ep.value_and_grad_fn(x, loss_fn, has_aux=True)
delta = ep.zeros_like(x)
epsilon = self.init_epsilon * ep.ones(x, len(x))
worst_norm = ep.norms.l2(flatten(ep.maximum(x - min_, max_ - x)), -1)
best_l2 = worst_norm
best_delta = delta
adv_found = ep.zeros(x, len(x)).bool()
for i in range(self.steps):
# perform cosine annealing of LR starting from 1.0 to 0.01
stepsize = (0.01 + (stepsize - 0.01) *
(1 + math.cos(math.pi * i / self.steps)) / 2)
x_adv = x + delta
_, logits, gradients = grad_and_logits(x_adv, classes)
gradients = normalize_gradient_l2_norms(gradients)
is_adversarial = criterion_(x_adv, logits)
l2 = ep.norms.l2(flatten(delta), axis=-1)
is_smaller = l2 <= best_l2
is_both = ep.logical_and(is_adversarial, is_smaller)
adv_found = ep.logical_or(adv_found, is_adversarial)
best_l2 = ep.where(is_both, l2, best_l2)
best_delta = ep.where(atleast_kd(is_both, x.ndim), delta,
best_delta)
# do step
delta = delta + stepsize * gradients
epsilon = epsilon * ep.where(is_adversarial, 1.0 - self.gamma,
1.0 + self.gamma)
epsilon = ep.minimum(epsilon, worst_norm)
# project to epsilon ball
delta *= atleast_kd(epsilon / ep.norms.l2(flatten(delta), -1),
x.ndim)
# clip to valid bounds
delta = ep.clip(x + delta, *model.bounds) - x
x_adv = x + best_delta
return restore_type(x_adv)
def __call__(
self,
model: Model,
inputs: T,
criterion: Union[Misclassification, TargetedMisclassification, T],
) -> T:
x, restore_type = ep.astensor_(inputs)
criterion_ = get_criterion(criterion)
del inputs, criterion
N = len(x)
if isinstance(criterion_, Misclassification):
targeted = False
classes = criterion_.labels
change_classes_logits = self.confidence
elif isinstance(criterion_, TargetedMisclassification):
targeted = True
classes = criterion_.target_classes
change_classes_logits = -self.confidence
else:
raise ValueError("unsupported criterion")
def is_adversarial(perturbed: ep.Tensor, logits: ep.Tensor) -> ep.Tensor:
if change_classes_logits != 0:
logits += ep.onehot_like(logits, classes, value=change_classes_logits)
return criterion_(perturbed, logits)
if classes.shape != (N,):
name = "target_classes" if targeted else "labels"
raise ValueError(
f"expected {name} to have shape ({N},), got {classes.shape}"
)
min_, max_ = model.bounds
rows = range(N)
def loss_fun(y_k: ep.Tensor, consts: ep.Tensor) -> Tuple[ep.Tensor, ep.Tensor]:
assert y_k.shape == x.shape
assert consts.shape == (N,)
logits = model(y_k)
if targeted:
c_minimize = best_other_classes(logits, classes)
c_maximize = classes
else:
c_minimize = classes
c_maximize = best_other_classes(logits, classes)
is_adv_loss = logits[rows, c_minimize] - logits[rows, c_maximize]
assert is_adv_loss.shape == (N,)
is_adv_loss = is_adv_loss + self.confidence
is_adv_loss = ep.maximum(0, is_adv_loss)
is_adv_loss = is_adv_loss * consts
squared_norms = flatten(y_k - x).square().sum(axis=-1)
loss = is_adv_loss.sum() + squared_norms.sum()
return loss, logits
loss_aux_and_grad = ep.value_and_grad_fn(x, loss_fun, has_aux=True)
consts = self.initial_const * ep.ones(x, (N,))
lower_bounds = ep.zeros(x, (N,))
upper_bounds = ep.inf * ep.ones(x, (N,))
best_advs = ep.zeros_like(x)
best_advs_norms = ep.ones(x, (N,)) * ep.inf
# the binary search searches for the smallest consts that produce adversarials
for binary_search_step in range(self.binary_search_steps):
if (
binary_search_step == self.binary_search_steps - 1
and self.binary_search_steps >= 10
):
# in the last iteration, repeat the search once
consts = ep.minimum(upper_bounds, 1e10)
# create a new optimizer find the delta that minimizes the loss
x_k = x
y_k = x
found_advs = ep.full(
x, (N,), value=False
).bool() # found adv with the current consts
loss_at_previous_check = ep.ones(x, (1,)) * ep.inf
for iteration in range(self.steps):
# square-root learning rate decay
stepsize = self.initial_stepsize * (1.0 - iteration / self.steps) ** 0.5
loss, logits, gradient = loss_aux_and_grad(y_k, consts)
x_k_old = x_k
x_k = project_shrinkage_thresholding(
y_k - stepsize * gradient, x, self.regularization, min_, max_
)
y_k = x_k + iteration / (iteration + 3.0) * (x_k - x_k_old)
if self.abort_early and iteration % (math.ceil(self.steps / 10)) == 0:
# after each tenth of the iterations, check progress
# TODO: loss is a scalar ep tensor. is this the bst way to
# implement the condition?
if not ep.all(loss <= 0.9999 * loss_at_previous_check):
break # stop optimization if there has been no progress
loss_at_previous_check = loss
found_advs_iter = is_adversarial(x_k, logits)
best_advs, best_advs_norms = apply_decision_rule(
self.decision_rule,
self.regularization,
best_advs,
best_advs_norms,
x_k,
x,
found_advs_iter,
)
found_advs = ep.logical_or(found_advs, found_advs_iter)
upper_bounds = ep.where(found_advs, consts, upper_bounds)
lower_bounds = ep.where(found_advs, lower_bounds, consts)
consts_exponential_search = consts * 10
consts_binary_search = (lower_bounds + upper_bounds) / 2
consts = ep.where(
ep.isinf(upper_bounds), consts_exponential_search, consts_binary_search
)
return restore_type(best_advs)
def run(
self,
model: Model,
inputs: T,
criterion: Union[Misclassification, TargetedMisclassification, T],
*,
early_stop: Optional[float] = None,
**kwargs: Any,
) -> T:
raise_if_kwargs(kwargs)
x, restore_type = ep.astensor_(inputs)
criterion_ = get_criterion(criterion)
del inputs, criterion, kwargs
N = len(x)
if isinstance(criterion_, Misclassification):
targeted = False
classes = criterion_.labels
change_classes_logits = self.confidence
elif isinstance(criterion_, TargetedMisclassification):
targeted = True
classes = criterion_.target_classes
change_classes_logits = -self.confidence
else:
raise ValueError("unsupported criterion")
def is_adversarial(perturbed: ep.Tensor,
logits: ep.Tensor) -> ep.Tensor:
if change_classes_logits != 0:
logits += ep.onehot_like(logits,
classes,
value=change_classes_logits)
return criterion_(perturbed, logits)
if classes.shape != (N, ):
name = "target_classes" if targeted else "labels"
raise ValueError(
f"expected {name} to have shape ({N},), got {classes.shape}")
bounds = model.bounds
to_attack_space = partial(_to_attack_space, bounds=bounds)
to_model_space = partial(_to_model_space, bounds=bounds)
x_attack = to_attack_space(x)
reconstsructed_x = to_model_space(x_attack)
rows = range(N)
def loss_fun(
delta: ep.Tensor, consts: ep.Tensor
) -> Tuple[ep.Tensor, Tuple[ep.Tensor, ep.Tensor]]:
assert delta.shape == x_attack.shape
assert consts.shape == (N, )
x = to_model_space(x_attack + delta)
logits = model(x)
if targeted:
c_minimize = best_other_classes(logits, classes)
c_maximize = classes # target_classes
else:
c_minimize = classes # labels
c_maximize = best_other_classes(logits, classes)
is_adv_loss = logits[rows, c_minimize] - logits[rows, c_maximize]
assert is_adv_loss.shape == (N, )
is_adv_loss = is_adv_loss + self.confidence
is_adv_loss = ep.maximum(0, is_adv_loss)
is_adv_loss = is_adv_loss * consts
squared_norms = flatten(x - reconstsructed_x).square().sum(axis=-1)
loss = is_adv_loss.sum() + squared_norms.sum()
return loss, (x, logits)
loss_aux_and_grad = ep.value_and_grad_fn(x, loss_fun, has_aux=True)
consts = self.initial_const * np.ones((N, ))
lower_bounds = np.zeros((N, ))
upper_bounds = np.inf * np.ones((N, ))
best_advs = ep.zeros_like(x)
best_advs_norms = ep.full(x, (N, ), ep.inf)
# the binary search searches for the smallest consts that produce adversarials
for binary_search_step in range(self.binary_search_steps):
if (binary_search_step == self.binary_search_steps - 1
and self.binary_search_steps >= 10):
# in the last binary search step, repeat the search once
consts = np.minimum(upper_bounds, 1e10)
# create a new optimizer find the delta that minimizes the loss
delta = ep.zeros_like(x_attack)
optimizer = AdamOptimizer(delta)
# tracks whether adv with the current consts was found
found_advs = np.full((N, ), fill_value=False)
loss_at_previous_check = np.inf
consts_ = ep.from_numpy(x, consts.astype(np.float32))
for step in range(self.steps):
loss, (perturbed,
logits), gradient = loss_aux_and_grad(delta, consts_)
delta += optimizer(gradient, self.stepsize)
if self.abort_early and step % (np.ceil(self.steps / 10)) == 0:
# after each tenth of the overall steps, check progress
if not (loss <= 0.9999 * loss_at_previous_check):
break # stop Adam if there has been no progress
loss_at_previous_check = loss
found_advs_iter = is_adversarial(perturbed, logits)
found_advs = np.logical_or(found_advs, found_advs_iter.numpy())
norms = flatten(perturbed - x).norms.l2(axis=-1)
closer = norms < best_advs_norms
new_best = ep.logical_and(closer, found_advs_iter)
new_best_ = atleast_kd(new_best, best_advs.ndim)
best_advs = ep.where(new_best_, perturbed, best_advs)
best_advs_norms = ep.where(new_best, norms, best_advs_norms)
upper_bounds = np.where(found_advs, consts, upper_bounds)
lower_bounds = np.where(found_advs, lower_bounds, consts)
consts_exponential_search = consts * 10
consts_binary_search = (lower_bounds + upper_bounds) / 2
consts = np.where(np.isinf(upper_bounds),
consts_exponential_search, consts_binary_search)
return restore_type(best_advs)
def run(
self,
model: Model,
inputs: T,
criterion: TargetedMisclassification,
*,
epsilon: float,
**kwargs: Any,
) -> T:
raise_if_kwargs(kwargs)
x, restore_type = ep.astensor_(inputs)
del inputs, kwargs
N = len(x)
if isinstance(criterion, TargetedMisclassification):
classes = criterion.target_classes
else:
raise ValueError("unsupported criterion")
if classes.shape != (N, ):
raise ValueError(
f"expected target_classes to have shape ({N},), got {classes.shape}"
)
noise_shape: Union[Tuple[int, int, int, int], Tuple[int, ...]]
channel_axis: Optional[int] = None
if self.reduced_dims is not None:
if x.ndim != 4:
raise NotImplementedError(
"only implemented for inputs with two spatial dimensions"
" (and one channel and one batch dimension)")
if self.channel_axis is None:
maybe_axis = get_channel_axis(model, x.ndim)
if maybe_axis is None:
raise ValueError(
"cannot infer the data_format from the model, please"
" specify channel_axis when initializing the attack")
else:
channel_axis = maybe_axis
else:
channel_axis = self.channel_axis % x.ndim
if channel_axis == 1:
noise_shape = (x.shape[1], *self.reduced_dims)
elif channel_axis == 3:
noise_shape = (*self.reduced_dims, x.shape[3])
else:
raise ValueError(
"expected 'channel_axis' to be 1 or 3, got {channel_axis}")
else:
noise_shape = x.shape[1:] # pragma: no cover
def is_adversarial(logits: ep.TensorType) -> ep.TensorType:
return ep.argmax(logits, 1) == classes
num_plateaus = ep.zeros(x, len(x))
mutation_probability = (ep.ones_like(num_plateaus) *
self.min_mutation_probability)
mutation_range = ep.ones_like(num_plateaus) * self.min_mutation_range
noise_pops = ep.uniform(x, (N, self.population, *noise_shape),
-epsilon, epsilon)
def calculate_fitness(logits: ep.TensorType) -> ep.TensorType:
first = logits[range(N), classes]
second = ep.log(ep.exp(logits).sum(1) - first)
return first - second
n_its_wo_change = ep.zeros(x, (N, ))
for step in range(self.steps):
fitness_l, is_adv_l = [], []
for i in range(self.population):
it = self.apply_noise(x, noise_pops[:, i], epsilon,
channel_axis)
logits = model(it)
f = calculate_fitness(logits)
a = is_adversarial(logits)
fitness_l.append(f)
is_adv_l.append(a)
fitness = ep.stack(fitness_l)
is_adv = ep.stack(is_adv_l, 1)
elite_idxs = ep.argmax(fitness, 0)
elite_noise = noise_pops[range(N), elite_idxs]
is_adv = is_adv[range(N), elite_idxs]
# early stopping
if is_adv.all():
return restore_type( # pragma: no cover
self.apply_noise(x, elite_noise, epsilon, channel_axis))
probs = ep.softmax(fitness / self.sampling_temperature, 0)
parents_idxs = np.stack(
[
self.choice(
self.population,
2 * self.population - 2,
replace=True,
p=probs[:, i],
) for i in range(N)
],
1,
)
mutations = [
ep.uniform(
x,
noise_shape,
-mutation_range[i].item() * epsilon,
mutation_range[i].item() * epsilon,
) for i in range(N)
]
new_noise_pops = [elite_noise]
for i in range(0, self.population - 1):
parents_1 = noise_pops[range(N), parents_idxs[2 * i]]
parents_2 = noise_pops[range(N), parents_idxs[2 * i + 1]]
# calculate crossover
p = probs[parents_idxs[2 * i], range(N)] / (
probs[parents_idxs[2 * i], range(N)] +
probs[parents_idxs[2 * i + 1],
range(N)])
p = atleast_kd(p, x.ndim)
p = ep.tile(p, (1, *noise_shape))
crossover_mask = ep.uniform(p, p.shape, 0, 1) < p
children = ep.where(crossover_mask, parents_1, parents_2)
# calculate mutation
mutation_mask = ep.uniform(children, children.shape)
mutation_mask = mutation_mask <= atleast_kd(
mutation_probability, children.ndim)
children = ep.where(mutation_mask, children + mutations[i],
children)
# project back to epsilon range
children = ep.clip(children, -epsilon, epsilon)
new_noise_pops.append(children)
noise_pops = ep.stack(new_noise_pops, 1)
# increase num_plateaus if fitness does not improve
# for 100 consecutive steps
n_its_wo_change = ep.where(elite_idxs == 0, n_its_wo_change + 1,
ep.zeros_like(n_its_wo_change))
num_plateaus = ep.where(n_its_wo_change >= 100, num_plateaus + 1,
num_plateaus)
n_its_wo_change = ep.where(n_its_wo_change >= 100,
ep.zeros_like(n_its_wo_change),
n_its_wo_change)
mutation_probability = ep.maximum(
self.min_mutation_probability,
0.5 * ep.exp(
math.log(0.9) * ep.ones_like(num_plateaus) * num_plateaus),
)
mutation_range = ep.maximum(
self.min_mutation_range,
0.5 * ep.exp(
math.log(0.9) * ep.ones_like(num_plateaus) * num_plateaus),
)
return restore_type(
self.apply_noise(x, elite_noise, epsilon, channel_axis))
def __call__(
self,
inputs,
labels,
*,
p,
candidates=10,
overshoot=0.02,
steps=50,
loss="logits",
):
"""
Parameters
----------
p : int or float
Lp-norm that should be minimzed, must be 2 or np.inf.
candidates : int
Limit on the number of the most likely classes that should
be considered. A small value is usually sufficient and much
faster.
overshoot : float
steps : int
Maximum number of steps to perform.
"""
if not (1 <= p <= np.inf):
raise ValueError
if p not in [2, np.inf]:
raise NotImplementedError
min_, max_ = self.model.bounds()
inputs = ep.astensor(inputs)
labels = ep.astensor(labels)
N = len(inputs)
logits = self.model.forward(inputs)
candidates = min(candidates, logits.shape[-1])
classes = logits.argsort(axis=-1).flip(axis=-1)
if candidates:
assert candidates >= 2
logging.info(f"Only testing the top-{candidates} classes")
classes = classes[:, :candidates]
i0 = classes[:, 0]
rows = ep.arange(inputs, N)
if loss == "logits":
def loss_fun(x: ep.Tensor, k: int) -> ep.Tensor:
logits = self.model.forward(x)
ik = classes[:, k]
l0 = logits[rows, i0]
lk = logits[rows, ik]
loss = lk - l0
return loss.sum(), (loss, logits)
elif loss == "crossentropy":
def loss_fun(x: ep.Tensor, k: int) -> ep.Tensor:
logits = self.model.forward(x)
ik = classes[:, k]
l0 = -ep.crossentropy(logits, i0)
lk = -ep.crossentropy(logits, ik)
loss = lk - l0
return loss.sum(), (loss, logits)
else:
raise ValueError(
f"expected loss to be 'logits' or 'crossentropy', got '{loss}'"
)
loss_aux_and_grad = ep.value_and_grad_fn(inputs,
loss_fun,
has_aux=True)
x = x0 = inputs
p_total = ep.zeros_like(x)
for step in range(steps):
# let's first get the logits using k = 1 to see if we are done
diffs = [loss_aux_and_grad(x, 1)]
_, (_, logits), _ = diffs[0]
is_adv = logits.argmax(axis=-1) != labels
if is_adv.all():
break
# then run all the other k's as well
# we could avoid repeated forward passes and only repeat
# the backward pass, but this cannot currently be done in eagerpy
diffs += [loss_aux_and_grad(x, k) for k in range(2, candidates)]
# we don't need the logits
diffs = [(losses, grad) for _, (losses, _), grad in diffs]
losses = ep.stack([l for l, _ in diffs], axis=1)
grads = ep.stack([g for _, g in diffs], axis=1)
assert losses.shape == (N, candidates - 1)
assert grads.shape == (N, candidates - 1) + x0.shape[1:]
# calculate the distances
distances = self.get_distances(losses, grads)
assert distances.shape == (N, candidates - 1)
# determine the best directions
best = distances.argmin(axis=1)
distances = distances[rows, best]
losses = losses[rows, best]
grads = grads[rows, best]
assert distances.shape == (N, )
assert losses.shape == (N, )
assert grads.shape == x0.shape
# apply perturbation
distances = distances + 1e-4 # for numerical stability
p_step = self.get_perturbations(distances, grads)
assert p_step.shape == x0.shape
p_total += p_step
# don't do anything for those that are already adversarial
x = ep.where(atleast_kd(is_adv, x.ndim), x,
x0 + (1.0 + overshoot) * p_total)
x = ep.clip(x, min_, max_)
return x.tensor
def __init__(self, x: ep.Tensor):
self.m = ep.zeros_like(x)
self.v = ep.zeros_like(x)
self.t = 0
def _binary_search_on_alpha(
self,
function_evolution: Callable[[ep.Tensor], ep.Tensor],
lower: ep.Tensor) -> ep.Tensor:
# Upper --> not adversarial / Lower --> adversarial
v_type = function_evolution(lower)
def get_alpha(theta: ep.Tensor) -> ep.Tensor:
return 1 - ep.astensor(self._cos(theta.raw * np.pi / 180))
check_opposite = lower > 0 # if param < 0: abs(param) doesn't work
# Get the upper range
upper = ep.where(
abs(lower) != self.theta_max,
lower + ep.sign(lower) * self.theta_max / self.T,
ep.zeros_like(lower)
)
mask_upper = (upper == 0)
while mask_upper.any():
# Find the correct lower/upper range
# if True in mask_upper, the range haven't been found
new_upper = lower + ep.sign(lower) * self.theta_max / self.T
potential_x = function_evolution(new_upper)
x = ep.where(
atleast_kd(mask_upper, potential_x.ndim),
potential_x,
ep.zeros_like(potential_x)
)
is_advs = self._is_adversarial(x)
lower = ep.where(ep.logical_and(mask_upper, is_advs), new_upper, lower)
upper = ep.where(ep.logical_and(mask_upper, is_advs.logical_not()), new_upper, upper)
mask_upper = mask_upper * is_advs
step = 0
over_gamma = abs(get_alpha(upper) - get_alpha(lower)) > self._BS_gamma
while step < self._BS_max_iteration and over_gamma.any():
mid_bound = (upper + lower) / 2
mid = ep.where(
atleast_kd(ep.logical_and(mid_bound != 0, over_gamma), v_type.ndim),
function_evolution(mid_bound),
ep.zeros_like(v_type)
)
is_adv = self._is_adversarial(mid)
mid_opp = ep.where(
atleast_kd(ep.logical_and(ep.astensor(check_opposite), over_gamma), mid.ndim),
function_evolution(-mid_bound),
ep.zeros_like(mid)
)
is_adv_opp = self._is_adversarial(mid_opp)
lower = ep.where(over_gamma * is_adv, mid_bound, lower)
lower = ep.where(over_gamma * is_adv.logical_not() * check_opposite * is_adv_opp, -mid_bound, lower)
upper = ep.where(over_gamma * is_adv.logical_not() * check_opposite * is_adv_opp, - upper, upper)
upper = ep.where(over_gamma * (abs(lower) != abs(mid_bound)), mid_bound, upper)
check_opposite = over_gamma * check_opposite * is_adv_opp * (lower > 0)
over_gamma = abs(get_alpha(upper) - get_alpha(lower)) > self._BS_gamma
step += 1
return ep.astensor(lower)
def _get_vector_random(self) -> ep.Tensor:
r = ep.zeros_like(self._originals)
r = getattr(ep, self.random_noise)(r, r.shape, 0, 1)
return ep.astensor(r)
def test_logical_or_manual(t: Tensor) -> None:
assert (ep.logical_or(t < 3, ep.zeros_like(t).bool()) == (t < 3)).all()
def run(
self,
model: Model,
inputs: T,
criterion: Union[Criterion, T],
*,
early_stop: Optional[float] = None,
**kwargs: Any,
) -> T:
raise_if_kwargs(kwargs)
x, restore_type = ep.astensor_(inputs)
del inputs, kwargs
criterion = get_criterion(criterion)
min_, max_ = model.bounds
logits = model(x)
classes = logits.argsort(axis=-1).flip(axis=-1)
if self.candidates is None:
candidates = logits.shape[-1] # pragma: no cover
else:
candidates = min(self.candidates, logits.shape[-1])
if not candidates >= 2:
raise ValueError( # pragma: no cover
f"expected the model output to have atleast 2 classes, got {logits.shape[-1]}"
)
logging.info(f"Only testing the top-{candidates} classes")
classes = classes[:, :candidates]
N = len(x)
rows = range(N)
loss_fun = self._get_loss_fn(model, classes)
loss_aux_and_grad = ep.value_and_grad_fn(x, loss_fun, has_aux=True)
x0 = x
p_total = ep.zeros_like(x)
for _ in range(self.steps):
# let's first get the logits using k = 1 to see if we are done
diffs = [loss_aux_and_grad(x, 1)]
_, (_, logits), _ = diffs[0]
is_adv = criterion(x, logits)
if is_adv.all():
break
# then run all the other k's as well
# we could avoid repeated forward passes and only repeat
# the backward pass, but this cannot currently be done in eagerpy
diffs += [loss_aux_and_grad(x, k) for k in range(2, candidates)]
# we don't need the logits
diffs_ = [(losses, grad) for _, (losses, _), grad in diffs]
losses = ep.stack([l for l, _ in diffs_], axis=1)
grads = ep.stack([g for _, g in diffs_], axis=1)
assert losses.shape == (N, candidates - 1)
assert grads.shape == (N, candidates - 1) + x0.shape[1:]
# calculate the distances
distances = self.get_distances(losses, grads)
assert distances.shape == (N, candidates - 1)
# determine the best directions
best = distances.argmin(axis=1)
distances = distances[rows, best]
losses = losses[rows, best]
grads = grads[rows, best]
assert distances.shape == (N, )
assert losses.shape == (N, )
assert grads.shape == x0.shape
# apply perturbation
distances = distances + 1e-4 # for numerical stability
p_step = self.get_perturbations(distances, grads)
assert p_step.shape == x0.shape
p_total += p_step
# don't do anything for those that are already adversarial
x = ep.where(atleast_kd(is_adv, x.ndim), x,
x0 + (1.0 + self.overshoot) * p_total)
x = ep.clip(x, min_, max_)
return restore_type(x)
def test_zeros_like(t: Tensor) -> Tensor:
return ep.zeros_like(t)
def run(
self,
model: Model,
inputs: T,
criterion: Union[Misclassification, TargetedMisclassification, T],
*,
starting_points: Optional[ep.Tensor] = None,
early_stop: Optional[float] = None,
**kwargs: Any,
) -> T:
raise_if_kwargs(kwargs)
criterion_ = get_criterion(criterion)
if isinstance(criterion_, Misclassification):
targeted = False
classes = criterion_.labels
elif isinstance(criterion_, TargetedMisclassification):
targeted = True
classes = criterion_.target_classes
else:
raise ValueError("unsupported criterion")
def loss_fn(
inputs: ep.Tensor, labels: ep.Tensor
) -> Tuple[ep.Tensor, Tuple[ep.Tensor, ep.Tensor]]:
logits = model(inputs)
if targeted:
c_minimize = best_other_classes(logits, labels)
c_maximize = labels # target_classes
else:
c_minimize = labels # labels
c_maximize = best_other_classes(logits, labels)
loss = logits[rows, c_minimize] - logits[rows, c_maximize]
return -loss.sum(), (logits, loss)
x, restore_type = ep.astensor_(inputs)
del inputs, criterion, kwargs
N = len(x)
# start from initialization points/attack
if starting_points is not None:
x1 = starting_points
else:
if self.init_attack is not None:
x1 = self.init_attack.run(model, x, criterion_)
else:
x1 = None
# if initial points or initialization attacks are provided,
# search for the boundary
if x1 is not None:
is_adv = get_is_adversarial(criterion_, model)
assert is_adv(x1).all()
lower_bound = ep.zeros(x, shape=(N, ))
upper_bound = ep.ones(x, shape=(N, ))
for _ in range(self.binary_search_steps):
epsilons = (lower_bound + upper_bound) / 2
mid_points = self.mid_points(x, x1, epsilons, model.bounds)
is_advs = is_adv(mid_points)
lower_bound = ep.where(is_advs, lower_bound, epsilons)
upper_bound = ep.where(is_advs, epsilons, upper_bound)
starting_points = self.mid_points(x, x1, upper_bound, model.bounds)
delta = starting_points - x
else:
# start from x0
delta = ep.zeros_like(x)
if classes.shape != (N, ):
name = "target_classes" if targeted else "labels"
raise ValueError(
f"expected {name} to have shape ({N},), got {classes.shape}")
min_, max_ = model.bounds
rows = range(N)
grad_and_logits = ep.value_and_grad_fn(x, loss_fn, has_aux=True)
if self.p != 0:
epsilon = ep.inf * ep.ones(x, len(x))
else:
epsilon = ep.ones(x, len(x)) if x1 is None \
else ep.norms.l0(flatten(delta), axis=-1)
if self.p != 0:
worst_norm = ep.norms.lp(flatten(ep.maximum(x - min_, max_ - x)),
p=self.p,
axis=-1)
else:
worst_norm = flatten(ep.ones_like(x)).bool().sum(axis=1).float32()
best_lp = worst_norm
best_delta = delta
adv_found = ep.zeros(x, len(x)).bool()
for i in range(self.steps):
# perform cosine annealing of learning rates
stepsize = (self.min_stepsize +
(self.max_stepsize - self.min_stepsize) *
(1 + math.cos(math.pi * i / self.steps)) / 2)
gamma = (0.001 + (self.gamma - 0.001) *
(1 + math.cos(math.pi * (i / self.steps))) / 2)
x_adv = x + delta
loss, (logits,
loss_batch), gradients = grad_and_logits(x_adv, classes)
is_adversarial = criterion_(x_adv, logits)
lp = ep.norms.lp(flatten(delta), p=self.p, axis=-1)
is_smaller = lp <= best_lp
is_both = ep.logical_and(is_adversarial, is_smaller)
adv_found = ep.logical_or(adv_found, is_adversarial)
best_lp = ep.where(is_both, lp, best_lp)
best_delta = ep.where(atleast_kd(is_both, x.ndim), delta,
best_delta)
# update epsilon
if self.p != 0:
distance_to_boundary = abs(loss_batch) / ep.norms.lp(
flatten(gradients), p=self.dual, axis=-1)
epsilon = ep.where(
is_adversarial,
ep.minimum(
epsilon * (1 - gamma),
ep.norms.lp(flatten(best_delta), p=self.p, axis=-1)),
ep.where(
adv_found, epsilon * (1 + gamma),
ep.norms.lp(flatten(delta), p=self.p, axis=-1) +
distance_to_boundary))
else:
epsilon = ep.where(
is_adversarial,
ep.minimum(
ep.minimum(epsilon - 1,
(epsilon * (1 - gamma)).astype(int).astype(
epsilon.dtype)),
ep.norms.lp(flatten(best_delta), p=self.p, axis=-1)),
ep.maximum(epsilon + 1,
(epsilon * (1 + gamma)).astype(int).astype(
epsilon.dtype)))
epsilon = ep.maximum(0, epsilon).astype(epsilon.dtype)
# clip epsilon
epsilon = ep.minimum(epsilon, worst_norm)
# computes normalized gradient update
grad_ = self.normalize(gradients, x=x,
bounds=model.bounds) * stepsize
# do step
delta = delta + grad_
# project according to the given norm
delta = self.project(x=x + delta, x0=x, epsilon=epsilon) - x
# clip to valid bounds
delta = ep.clip(x + delta, *model.bounds) - x
x_adv = x + best_delta
return restore_type(x_adv)
def __call__(
self,
inputs,
labels,
*,
target_classes=None,
binary_search_steps=9,
max_iterations=10000,
confidence=0,
initial_learning_rate=1e-2,
regularization=1e-2,
initial_const=1e-3,
abort_early=True,
decision_rule="EN",
):
x_0 = ep.astensor(inputs)
N = len(x_0)
assert decision_rule in ("EN", "L1")
targeted = target_classes is not None
if targeted:
labels = None
target_classes = ep.astensor(target_classes)
assert target_classes.shape == (N, )
is_adv = partial(targeted_is_adv,
target_classes=target_classes,
confidence=confidence)
else:
labels = ep.astensor(labels)
assert labels.shape == (N, )
is_adv = partial(untargeted_is_adv,
labels=labels,
confidence=confidence)
min_, max_ = self.model.bounds()
rows = np.arange(N)
def loss_fun(y_k: ep.Tensor, consts: ep.Tensor) -> ep.Tensor:
assert y_k.shape == x_0.shape
assert consts.shape == (N, )
logits = self.model.forward(y_k)
if targeted:
c_minimize = best_other_classes(logits, target_classes)
c_maximize = target_classes
else:
c_minimize = labels
c_maximize = best_other_classes(logits, labels)
is_adv_loss = logits[rows, c_minimize] - logits[rows, c_maximize]
assert is_adv_loss.shape == (N, )
is_adv_loss = is_adv_loss + confidence
is_adv_loss = ep.maximum(0, is_adv_loss)
is_adv_loss = is_adv_loss * consts
squared_norms = flatten(y_k - x_0).square().sum(axis=-1)
loss = is_adv_loss.sum() + squared_norms.sum()
return loss, (y_k, logits)
loss_aux_and_grad = ep.value_and_grad_fn(x_0, loss_fun, has_aux=True)
consts = initial_const * np.ones((N, ))
lower_bounds = np.zeros((N, ))
upper_bounds = np.inf * np.ones((N, ))
best_advs = ep.zeros_like(x_0)
best_advs_norms = ep.ones(x_0, (N, )) * np.inf
# the binary search searches for the smallest consts that produce adversarials
for binary_search_step in range(binary_search_steps):
if (binary_search_step == binary_search_steps - 1
and binary_search_steps >= 10):
# in the last iteration, repeat the search once
consts = np.minimum(upper_bounds, 1e10)
# create a new optimizer find the delta that minimizes the loss
# TODO: rewrite this once eagerpy supports .copy()
x_k = x_0 # ep.zeros_like(x_0) + x_0
y_k = x_0 # ep.zeros_like(x_0) + x_0
found_advs = np.full(
(N, ), fill_value=False) # found adv with the current consts
loss_at_previous_check = np.inf
consts_ = ep.from_numpy(x_0, consts.astype(np.float32))
for iteration in range(max_iterations):
# square-root learning rate decay
learning_rate = (initial_learning_rate *
(1.0 - iteration / max_iterations)**0.5)
loss, (x, logits), gradient = loss_aux_and_grad(x_k, consts_)
x_k_old = x_k
x_k = project_shrinkage_thresholding(
y_k - learning_rate * gradient, x_0, regularization, min_,
max_)
y_k = x_k + iteration / (iteration + 3) - (x_k - x_k_old)
if abort_early and iteration % (np.ceil(
max_iterations / 10)) == 0:
# after each tenth of the iterations, check progress
if not (loss <= 0.9999 * loss_at_previous_check):
break # stop Adam if there has been no progress
loss_at_previous_check = loss
found_advs_iter = is_adv(logits)
best_advs, best_advs_norms = apply_decision_rule(
decision_rule,
regularization,
best_advs,
best_advs_norms,
x_k,
x_0,
found_advs_iter,
)
found_advs = np.logical_or(found_advs, found_advs_iter.numpy())
upper_bounds = np.where(found_advs, consts, upper_bounds)
lower_bounds = np.where(found_advs, lower_bounds, consts)
consts_exponential_search = consts * 10
consts_binary_search = (lower_bounds + upper_bounds) / 2
consts = np.where(np.isinf(upper_bounds),
consts_exponential_search, consts_binary_search)
return best_advs.tensor
def __init__(self, x):
self.m = ep.zeros_like(x)
self.v = ep.zeros_like(x)
self.t = 0
def __call__(
self,
inputs,
labels,
*,
target_classes=None,
binary_search_steps=9,
max_iterations=10000,
confidence=0,
learning_rate=1e-2,
initial_const=1e-3,
abort_early=True,
):
x = ep.astensor(inputs)
N = len(x)
targeted = target_classes is not None
if targeted:
labels = None
target_classes = ep.astensor(target_classes)
assert target_classes.shape == (N, )
is_adv = partial(targeted_is_adv,
target_classes=target_classes,
confidence=confidence)
else:
labels = ep.astensor(labels)
assert labels.shape == (N, )
is_adv = partial(untargeted_is_adv,
labels=labels,
confidence=confidence)
bounds = self.model.bounds()
to_attack_space = partial(_to_attack_space, bounds=bounds)
to_model_space = partial(_to_model_space, bounds=bounds)
x_attack = to_attack_space(x)
reconstsructed_x = to_model_space(x_attack)
rows = np.arange(N)
def loss_fun(delta: ep.Tensor, consts: ep.Tensor) -> ep.Tensor:
assert delta.shape == x_attack.shape
assert consts.shape == (N, )
x = to_model_space(x_attack + delta)
logits = ep.astensor(self.model.forward(x.tensor))
if targeted:
c_minimize = best_other_classes(logits, target_classes)
c_maximize = target_classes
else:
c_minimize = labels
c_maximize = best_other_classes(logits, labels)
is_adv_loss = logits[rows, c_minimize] - logits[rows, c_maximize]
assert is_adv_loss.shape == (N, )
is_adv_loss = is_adv_loss + confidence
is_adv_loss = ep.maximum(0, is_adv_loss)
is_adv_loss = is_adv_loss * consts
squared_norms = flatten(x - reconstsructed_x).square().sum(axis=-1)
loss = is_adv_loss.sum() + squared_norms.sum()
return loss, (x, logits)
loss_aux_and_grad = ep.value_and_grad_fn(x, loss_fun, has_aux=True)
consts = initial_const * np.ones((N, ))
lower_bounds = np.zeros((N, ))
upper_bounds = np.inf * np.ones((N, ))
best_advs = ep.zeros_like(x)
best_advs_norms = ep.ones(x, (N, )) * np.inf
# the binary search searches for the smallest consts that produce adversarials
for binary_search_step in range(binary_search_steps):
if (binary_search_step == binary_search_steps - 1
and binary_search_steps >= 10):
# in the last iteration, repeat the search once
consts = np.minimum(upper_bounds, 1e10)
# create a new optimizer find the delta that minimizes the loss
delta = ep.zeros_like(x_attack)
optimizer = AdamOptimizer(delta)
found_advs = np.full(
(N, ), fill_value=False) # found adv with the current consts
loss_at_previous_check = np.inf
consts_ = ep.from_numpy(x, consts.astype(np.float32))
for iteration in range(max_iterations):
loss, (perturbed,
logits), gradient = loss_aux_and_grad(delta, consts_)
delta += optimizer(gradient, learning_rate)
if abort_early and iteration % (np.ceil(
max_iterations / 10)) == 0:
# after each tenth of the iterations, check progress
if not (loss <= 0.9999 * loss_at_previous_check):
break # stop Adam if there has been no progress
loss_at_previous_check = loss
found_advs_iter = is_adv(logits)
found_advs = np.logical_or(found_advs, found_advs_iter.numpy())
norms = flatten(perturbed - x).square().sum(axis=-1).sqrt()
closer = norms < best_advs_norms
new_best = closer.float32() * found_advs_iter.float32()
best_advs = (
atleast_kd(new_best, best_advs.ndim) * perturbed +
(1 - atleast_kd(new_best, best_advs.ndim)) * best_advs)
best_advs_norms = new_best * norms + (
1 - new_best) * best_advs_norms
upper_bounds = np.where(found_advs, consts, upper_bounds)
lower_bounds = np.where(found_advs, lower_bounds, consts)
consts_exponential_search = consts * 10
consts_binary_search = (lower_bounds + upper_bounds) / 2
consts = np.where(np.isinf(upper_bounds),
consts_exponential_search, consts_binary_search)
return best_advs.tensor
