ai-privacy-toolkit/apt/risk/data_assessment/attack_strategy_utils.py
Maya Anderson dbb958f791 Merge pull request #71 from IBM/dataset_assessment
Add AI privacy Dataset assessment module with two attack implementations.

Signed-off-by: Maya Anderson <mayaa@il.ibm.com>
2023-03-20 14:21:29 +02:00

70 lines
3 KiB
Python

import abc
import numpy as np
from sklearn.neighbors import NearestNeighbors
from tqdm import tqdm
from apt.utils.datasets import ArrayDataset
class AttackStrategyUtils(abc.ABC):
"""
Abstract base class for common utilities of various privacy attack strategies.
"""
pass
class KNNAttackStrategyUtils(AttackStrategyUtils):
"""
Common utilities for attack strategy based on KNN distances.
"""
def __init__(self, use_batches: bool = False, batch_size: int = 10) -> None:
"""
:param use_batches: Use batches with a progress meter or not when finding KNNs for query set
:param batch_size: if use_batches=True, the size of batch_size should be > 0
"""
self.use_batches = use_batches
self.batch_size = batch_size
if use_batches:
if batch_size < 1:
raise ValueError(f"When using batching batch_size should be > 0, and not {batch_size}")
def fit(self, knn_learner: NearestNeighbors, dataset: ArrayDataset):
knn_learner.fit(dataset.get_samples())
def find_knn(self, knn_learner: NearestNeighbors, query_samples: ArrayDataset, distance_processor=None):
"""
Nearest neighbor search function.
:param query_samples: query samples, to which nearest neighbors are to be found
:param knn_learner: unsupervised learner for implementing neighbor searches, after it was fitted
:param distance_processor: function for processing the distance into another more relevant metric per sample.
Its input is an array representing distances (the distances returned by NearestNeighbors.kneighbors() ), and
the output should be another array with distance-based values that enable to compute the final risk score
:return:
distances of the query samples to their nearest neighbors, or a metric based on that distance and calculated
by the distance_processor function
"""
samples = query_samples.get_samples()
if not self.use_batches:
distances, _ = knn_learner.kneighbors(samples, return_distance=True)
if distance_processor:
return distance_processor(distances)
else:
return distances
distances = []
for i in tqdm(range(len(samples) // self.batch_size)):
x_batch = samples[i * self.batch_size:(i + 1) * self.batch_size]
x_batch = np.reshape(x_batch, [self.batch_size, -1])
# dist_batch: distance between every query sample in batch to its KNNs among training samples
dist_batch, _ = knn_learner.kneighbors(x_batch, return_distance=True)
# The probability of each sample to be generated
if distance_processor:
distance_based_metric_per_sample_batch = distance_processor(dist_batch)
distances.append(distance_based_metric_per_sample_batch)
else:
distances.append(dist_batch)
return np.concatenate(distances)