Tilewise Domain-Separated Selective Encryption for Remote Sensing Imagery under Chosen-Plaintext Attacks

TL;DR

This paper introduces TDS-SE, a tilewise domain-separated selective encryption method for remote sensing images that enhances security against chosen-plaintext attacks by preventing structural leakage through per-tile key derivation and external ROI masks.

Contribution

The paper proposes a novel tilewise domain-separated encryption scheme with explicit domain separation and external ROI masks, along with a structured evaluation protocol for security against realistic attacks.

Findings

Per-tile domain separation reduces transferability of structural leakage.

Adding frame freshness improves robustness to ROI assumptions.

Selective encryption remains effective under consistent tiling and ROI policies.

Abstract

Selective image encryption is common in remote sensing systems because it protects sensitive regions of interest (ROI) while limiting computational cost. However, many selective designs enable cross-tile structural leakage under chosen-plaintext attacks when secret-dependent transformations are reused across spatial positions. This paper proposes Tilewise Domain-Separated Selective Encryption (TDS-SE), where per-tile (and optionally per-frame) keys are derived from a master secret via HKDF with explicit domain separation, and ROI masks are treated strictly as external side information. Structural leakage is evaluated using two reconstruction-based distinguishers -- a linear model and a lightweight convolutional neural network -- under multiple attack settings. Experiments on RESISC45 and SEN12MS cover ablation tests, cross-position transferability, cross-sample generalization, and ROI-knowledge asymmetry. Results show that per-tile domain separation reduces position-conditioned transfer for the linear probe, and that adding frame freshness improves robustness to imperfect ROI assumptions for the CNN probe. Cross-sample generalization exhibits mixed behavior across settings, consistent with an empirical evaluation perspective, while selective-encryption functionality is preserved under the same tiling and ROI policy. Beyond the method itself, the paper provides a structured protocol for evaluating selective encryption under realistic attacker capabilities.