octra-labs/hfhe-challenge

This repository hosts a cryptography bounty challenge rather than a piece of software meant to be installed or run for everyday use. It is the second version of a puzzle where the goal is to recover a plaintext value hidden inside a file called secret.ct, which contains a private key and metadata tied to a specific cryptocurrency wallet address. The first version of this challenge was canceled because its public files included an extra commitment value that accidentally let solvers check structured guesses offline, which is considered an unfair shortcut. That flaw has been removed in this second version. No hints beyond the provided files are given. If someone successfully recovers the plaintext, they can use it with the Octra web client to access the wallet and claim a reward of 500,000 OCT, the project's token. Contacting the project's email address afterward can unlock an additional 500,000 OCT, bringing the total possible reward to 1,000,000 OCT or an equivalent amount in USDC. The bounty package bundles several files: a manifest, parameter file, public key, a commitment text file, the ciphertext itself, and C++ source files used to generate and serialize the challenge artifact. The ciphertext was produced using a specific pinned commit of a separate tool called pvac_hfhe_cpp, and the README recommends using that exact version when trying to reproduce the artifact format or attempt an attack. An update posted July 11 added extra cryptanalysis material called LPN samples, which expose a secondary mathematical target related to a value called S, separate from the main goal of recovering the wallet's plaintext. A verification tool was also added so solvers can confirm that the LPN samples are properly linked to the original secret.ct file. The README does not state a software license for this repository.