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Wed, 21 Jan 2026 23:09:29 -0800 (PST) X-Received: by 2002:a05:6808:1803:b0:45c:8183:8c6f with SMTP id 5614622812f47-45c9d85906fmr8445645b6e.47.1769065769533; Wed, 21 Jan 2026 23:09:29 -0800 (PST) Received: by 2002:a05:690c:e3ce:b0:786:8d90:70d8 with SMTP id 00721157ae682-793c7d804b2ms7b3; Wed, 21 Jan 2026 23:01:35 -0800 (PST) X-Received: by 2002:a05:690c:7010:b0:78c:6ae6:3c7c with SMTP id 00721157ae682-793c6824cf7mr142321327b3.48.1769065293811; Wed, 21 Jan 2026 23:01:33 -0800 (PST) Date: Wed, 21 Jan 2026 23:01:33 -0800 (PST) From: Giulio Golinelli To: Bitcoin Development Mailing List Message-Id: <16e01530-e9dd-481f-8c7f-ca9ccafcfcden@googlegroups.com> Subject: [bitcoindev] Falcon Post-Quantum Signature Scheme Proposal MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_1120_1588464649.1769065293375" X-Original-Sender: golinelli.giulio13@gmail.com Precedence: list Mailing-list: list bitcoindev@googlegroups.com; contact bitcoindev+owners@googlegroups.com List-ID: X-Google-Group-Id: 786775582512 List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , X-Spam-Score: -0.5 (/) ------=_Part_1120_1588464649.1769065293375 Content-Type: multipart/alternative; boundary="----=_Part_1121_1824863990.1769065293375" ------=_Part_1121_1824863990.1769065293375 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi everyone, I am to share a technical demonstration and benchmarking project that=20 integrates the Falcon post-quantum signature scheme (Falcon-512) into=20 Bitcoin Core, implemented as a soft-fork within the classic P2WPKH mode.=20 This work aims to provide a practical reference for possible future Falcon= =20 adoption, especially as it approaches FIPS standardization. You can find details at this fork=20 . *Why Falcon?* Falcon is a lattice-based, post-quantum digital signature scheme designed= =20 to be secure against quantum attacks. Unlike other PQC candidates such as= =20 SPHINCS+ and ML-DSA, Falcon offers significantly smaller signature and=20 public key sizes, as well as efficient signing and verification times. It= =20 is implemented in pure C and does not require external dependencies. *Benchmarking & Results* Aspect Falcon ECDSA Public Key Size (B) 897 33 Signature Size (B) 655 71 Verification Time (=CE=BCs) 57 120 Verification time is more critical than signature creation time in Bitcoin,= =20 since signature creation is performed by clients (wallets), while nodes=20 focus on verification. *Integration* - Falcon was included into the codebase from the original GitHub=20 repository. - The build system (CMakeLists.txt) was updated to support Falcon. - Falcon verification has been soft-fork enabled via a new script=20 verification flag. *Next Steps & Reference* This project serves as a practical demonstration of Falcon=E2=80=99s promis= ing=20 performance, highlighting its advantages over currently selected=20 post-quantum signature algorithms such as SPHINCS+ and ML-DSA, which face= =20 significant time and space limitations. As Falcon approaches FIPS=20 standardization, this work aims to provide a reference for future adoption= =20 and integration in Bitcoin. Let me know what you think and if this could be of interest for which case= =20 I can complement the project by integrating Falcon into all the other=20 spending paths. I also look forward to development/integration corrections. Best regards, Giulio --=20 You received this message because you are subscribed to the Google Groups "= Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to bitcoindev+unsubscribe@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/= 16e01530-e9dd-481f-8c7f-ca9ccafcfcden%40googlegroups.com. ------=_Part_1121_1824863990.1769065293375 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi everyone,

I am to share a technical demonstration and benchma= rking project that integrates the Falcon post-quantum signature scheme (Fal= con-512) into Bitcoin Core, implemented as a soft-fork within the classic P= 2WPKH mode. This work aims to provide a practical reference for possible fu= ture Falcon adoption, especially as it approaches FIPS standardization.
You can find details at this fork.

Why Falcon?Falcon is a lattice-based, post-quantum digital signature scheme designe= d to be secure against quantum attacks. Unlike other PQC candidates such as= SPHINCS+ and ML-DSA, Falcon offers significantly smaller signature and pub= lic key sizes, as well as efficient signing and verification times. It is i= mplemented in pure C and does not require external dependencies.

Benchmarking & Results
Aspect=C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0Falcon= =C2=A0 =C2=A0 ECDSA
Public Key Size (B) 897=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A033
Signature Size (B)<= span style=3D"white-space: pre;"> 655 =C2=A0 =C2=A0 =C2=A0 =C2=A0 71
Verification Time (=CE=BCs)<= span style=3D"white-space: pre;"> 57bitcoind= ev+unsubscribe@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/bitcoind= ev/16e01530-e9dd-481f-8c7f-ca9ccafcfcden%40googlegroups.com.
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