Finite-field representation and cryptanalytic TMTO: Java/Rust research repo + ePrint draft

[qoosmo]

Research project modernization

This PR develops the original M2P SCCI master's research project at
Ensimag-UJF into a reproducible research repository and an evolving IACR
ePrint paper draft.

Original researchers:

• Abdourahmane Sakho
• Ali Mkhida
• Maad El Yadari

Historical artifact

docs/original-presentation.pdf is preserved byte-for-byte with its original
logos and layout. It is never rewritten into the modern paper.

ePrint track

The repository contains a separate 12-page working paper:

Representation and Time-Memory Tradeoffs in Symmetric Cryptography:
Finite-Field Basis Transformations for AES and Reproducible Hellman Experiments

The paper reconstructs the recoverable finite-field mathematics from the
historical presentation and separates historical statements, verified
identities, measured modern results, and future work.

Java + Rust

Java 17 remains the current reference semantics. This PR adds a Rust reference
implementation covering:

• reduced DES effective-bit key encoding and odd parity;
• DES/ECB with PKCS#5-compatible padding;
• the historical reduction;
• exhaustive search;
• Hellman chains;
• distinguished-point chains;
• exact coverage analysis.

A shared CSV fixture is consumed by Java and Rust to verify key encodings,
ciphertexts, reductions, and chain endpoints. No Rust performance claim is made
yet.

Verified Java experiment

Method	Median exact coverage	Exact recovery
Exhaustive	100.0%	30/30
Hellman	16.8%	4/30
Distinguished points	15.4%	3/30

Historical mathematics

The repository includes a verifier for the slide-derived GF(16)
multiplication/squaring identities and the exact 8x8 isomorphism matrix pair.

ePrint authorship

Historical credit is preserved. The future ePrint author list will be finalized
with the original collaborators before submission.