[URGENT] Critical Security Disclosure: Deterministic Key Recovery via Lattice Instantiation Flaw (Emails Unanswered)

[shanyu-ux]

Summary

I am writing to urgently escalate a Critical Vulnerability disclosure regarding the core lattice instantiation logic in tfhe-rs / Concrete.

I have identified an Axiomatic Geometric Flaw that allows for Deterministic Private Key Recovery (not theoretical; proven via implementation).

Disclosure Status

I have sent detailed reports, including a Proof-of-Concept (Rust/AMX optimized) and a Theoretical Abstract, to the following channels approx. 12 hours ago:

• bounty@zama.ai
• CC'd NIST PQC team contacts

Subject: CRITICAL: Deterministic Key Recovery in TFHE/Concrete Primitives via Geometric Spectral Gap Analysis

Proof of Impact (Sanitized)

To verify the severity before disclosure:

1. I utilized the public instance generator on the Zama official website.
2. Using my geometric derivation (NCGD), I successfully recovered the Private Key from the local instance artifacts.
3. The recovery process took approximately 2 seconds using hardware acceleration.

Request

I have received no acknowledgment. Given the Critical nature of this flaw (Key Recovery), please check your security inbox immediately or provide a secure PGP channel for re-submission.

I will NOT post technical details or the PoC here to prevent zero-day exploitation.

Best,
Shan YU
alanazucena2084@gmail.com

[zama-bot]

Hello shanyu-ux,

Thank you for your Grant application! Our team will review and add comments in your issue! In the meantime:

1. Join the FHE.org discord server for any questions (pick the Zama library channel you will use).
2. Ask questions privately: bounty@zama.ai.

[aquint-zama]

hello @shanyu-ux

If you have found a security issue in tfhe-rs please use Security Advisories, also we cant accept zip files for security reason but you could add code in your security advisory if needed.
Closing the issue here.

[shanyu-ux]

Subject: Re: [URGENT] Critical Security Disclosure: Deterministic Key Recovery via Lattice Instantiation Flaw Hi Alex, Understood regarding the zip file policy. The artifact was encrypted precisely to prevent automated flagging, but I respect your gateway restrictions. However, the Criticality of this vulnerability (Deterministic Private Key Recovery in < 2 seconds) requires immediate attention. It is an axiomatic flaw in the underlying tfhe-rs geometry, not a simple bug. To facilitate secure delivery of the Proof-of-Concept (PoC) and the Technical Whitepaper: GitHub Security Advisory: I will open a Private Advisory on the tfhe-rs repository as requested. Alternative Delivery: Since the PoC involves a compiled binary (macOS AMX accelerated) which might be blocked by GitHub uploads as well, I can provide a password-protected Google Drive link or a Magic Wormhole transfer if preferred. Please confirm: Does Zama acknowledge the receipt of this disclosure timeline (initial email sent 12 hours ago)? I have already coordinated with CNVD and NIST for responsible disclosure. Regards, Shan YU 获取Outlook for Android<https://aka.ms/AAb9ysg>

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________________________________ From: Alex Quint ***@***.***> Sent: Tuesday, December 2, 2025 11:04:36 PM To: zama-ai/bounty-program ***@***.***> Cc: Schànn-Rafa?l der Verbannte ***@***.***>; Mention ***@***.***> Subject: Re: [zama-ai/bounty-program] [URGENT] Critical Security Disclosure: Deterministic Key Recovery via Lattice Instantiation Flaw (Emails Unanswered) (Issue #166) [https://avatars.githubusercontent.com/u/86411313?s=20&v=4]aquint-zama left a comment (zama-ai/bounty-program#166)<#166 (comment)> hello @shanyu-ux<https://github.com/shanyu-ux> If you have found a security issue in tfhe-rs please use Security Advisories, also we cant accept zip files for security reason but you could add code in your security advisory if needed. Closing the issue here. ― Reply to this email directly, view it on GitHub<#166 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/B2OBLYKBRRJHAQGU7DWIR5D37WTAJAVCNFSM6AAAAACNXDYDO6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTMMBSGUYDKNZVGI>. You are receiving this because you were mentioned.Message ID: ***@***.***>