CryptoDB
Efficient strong 2-source non-malleable extractor for any linear min-entropy
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| Conference: | CRYPTO 2025 |
| Abstract: | Randomness is a fundamental requirement in cryptographic systems, enabling secure encryption, commitments, and zero-knowledge proofs. However, real-world randomness sources often suffer from weaknesses that adversaries can exploit, leading to significant security vulnerabilities. While deterministic randomness extraction from a single min-entropy source is impossible, two-source extractors provide a robust solution by generating nearly uniform randomness from two independent weak sources. Moreover, cryptographic systems must also be resilient to leakage and tampering attacks, necessitating the development of non-malleable two-source extractors. In this work, we construct a two-source non-malleable extractor in the Common Reference String (CRS) model, where a random low-degree polynomial is sampled once and made accessible to independent random sources, the distinguisher, and the tamperer. Our extractor requires only linear min-entropy in both sources and doesn't rely on strong computational assumptions, in contrast to prior constructions requiring computational assumptions such as sub-exponential hardness of the Decisional Diffie-Hellman (DDH) problem. Notably, our construction builds upon and relies on the recent breakthrough proof of the polynomial Freiman-Ruzsa conjecture. Our results advance the state of non-malleable cryptographic primitives, with applications in secure storage, leakage-resilient cryptography, and privacy amplification. By eliminating the need for strong computational hardness assumptions, our techniques provide a more foundational and widely applicable method for randomness extraction. |
BibTeX
@inproceedings{crypto-2025-35804,
title={Efficient strong 2-source non-malleable extractor for any linear min-entropy},
publisher={Springer-Verlag},
author={Divesh Aggarwal and Pranjal Dutta and Saswata Mukherjee and Satyajeet Nagargoje and Maciej Obremski},
year=2025
}