Alkaid: Resilience to Edit Errors in Provably Secure Steganography via Distance-Constrained Encoding

2026-03-06

AI Summary

This work addresses the lack of robustness in existing provably secure steganographic systems against edit errors—such as insertions, deletions, and substitutions—which stems from their reliance on exact synchronization and absence of error-correction mechanisms. The paper proposes the first scheme that directly embeds edit-distance constraints into provably secure steganographic encoding by ensuring that codewords corresponding to distinct messages maintain a minimum edit distance. Violating codewords are merged to enable deterministic error tolerance, thereby enhancing robustness while preserving information-theoretic security. Coupled with an efficient block-wise batched implementation, the method achieves decoding success rates of 99%–100% across various error channels, an embedding capacity of 0.2 bits per token, and an encoding rate of 6.72 bits per second, significantly outperforming the current state-of-the-art.

Technology Category

• Computer Vision: Adversarial Attacks & Robustness
• Reasoning under Uncertainty: Stochastic Optimization
• Natural Language Processing: Safety and Robustness

Application Category

• Security and Privacy: Large-scale security measurements
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

While provably secure steganography provides strong concealment by ensuring stego carriers are indistinguishable from natural samples, such systems remain vulnerable to real-world edit errors (e.g., insertions, deletions, substitutions) because their decoding depends on perfect synchronization and lacks error-correcting capability. To bridge this gap, we propose Alkaid, a provably secure steganographic scheme resilient to edit errors via distance-constrained encoding. The key innovation integrates the minimum distance decoding principle directly into the encoding process by enforcing a strict lower bound on the edit distance between codewords of different messages. Specifically, if two candidate codewords violate this bound, they are merged to represent the same message, thereby guaranteeing reliable recovery. While maintaining provable security, we theoretically prove that Alkaid offers deterministic robustness against bounded errors. To implement this scheme efficiently, we adopt block-wise and batch processing. Extensive experiments demonstrate that Alkaid achieves decoding success rates of 99\% to 100\% across diverse error channels, delivers a payload of 0.2 bits per token for high embedding capacity, and maintains an encoding speed of 6.72 bits per second, significantly surpassing state-of-the-art (SOTA) methods in robustness, capacity, and efficiency.

Problem

• steganography
• edit errors
• error resilience
• provable security
• synchronization

Innovation

• provably secure steganography
• edit error resilience
• distance-constrained encoding
• minimum edit distance
• deterministic robustness