Post-Quantum Sanitizable Signatures from McEliece-Based Chameleon Hashing

Fuente: arXiv
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Hauptverfasser: Ahmad, Shahzad, Rass, Stefan, Seyedi, Zahra
Format: Preprint
Veröffentlicht: 2026
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author Ahmad, Shahzad
Rass, Stefan
Seyedi, Zahra
author_facet Ahmad, Shahzad
Rass, Stefan
Seyedi, Zahra
contents We introduce a novel post-quantum sanitizable signature scheme constructed upon a chameleon hash function derived from the McEliece cryptosystem. In this design, the designated sanitizer possesses the inherent trapdoor of a Goppa code, which facilitates controlled collision-finding via Patterson decoding. This mechanism enables authorized modification of specific message blocks while ensuring all other content remains immutably bound. We provide formal security definitions and rigorous proofs of existential unforgeability and immutability, grounded in the hardness of syndrome decoding in the random-oracle model, where a robust random oracle thwarts trivial linear hash collisions. A key innovation lies in our precise characterization of the transparency property: by imposing a specific weight constraint on the randomizers generated by the signer, we achieve perfect transparency, rendering sanitized signatures indistinguishable from freshly signed ones. This work establishes the first transparent, code-based, post-quantum sanitizable signature scheme, offering strong theoretical guarantees and a pathway for practical deployment in long-term secure applications.
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id arxiv_https___arxiv_org_abs_2602_20657
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Post-Quantum Sanitizable Signatures from McEliece-Based Chameleon Hashing
Ahmad, Shahzad
Rass, Stefan
Seyedi, Zahra
Cryptography and Security
We introduce a novel post-quantum sanitizable signature scheme constructed upon a chameleon hash function derived from the McEliece cryptosystem. In this design, the designated sanitizer possesses the inherent trapdoor of a Goppa code, which facilitates controlled collision-finding via Patterson decoding. This mechanism enables authorized modification of specific message blocks while ensuring all other content remains immutably bound. We provide formal security definitions and rigorous proofs of existential unforgeability and immutability, grounded in the hardness of syndrome decoding in the random-oracle model, where a robust random oracle thwarts trivial linear hash collisions. A key innovation lies in our precise characterization of the transparency property: by imposing a specific weight constraint on the randomizers generated by the signer, we achieve perfect transparency, rendering sanitized signatures indistinguishable from freshly signed ones. This work establishes the first transparent, code-based, post-quantum sanitizable signature scheme, offering strong theoretical guarantees and a pathway for practical deployment in long-term secure applications.
title Post-Quantum Sanitizable Signatures from McEliece-Based Chameleon Hashing
topic Cryptography and Security
url https://arxiv.org/abs/2602.20657