Till now, each Bitcoin Enchancment Proposal (BIP) that wanted cryptographic primitives needed to reinvent the wheel. Each got here bundled with its personal customized Python implementation of the secp256k1 elliptic curve and associated algorithms, every subtly totally different from each other. These inconsistencies launched quiet liabilities and made reviewing BIPs unnecessarily difficult. This drawback was not too long ago highlighted in Bitcoin Optech E-newsletter #348, and it’s one thing a minimum of a handful of builders within the Bitcoin improvement neighborhood have lengthy felt: there must be a unified, reusable commonplace for cryptographic BIP reference secp256k1 code.
Final week, Jonas Nick and Tim Ruffing of Blockstream analysis and Sebastian Falbesoner made massive progress in direction of this. As a part of their current ChillDKG proposal, the workforce launched secp256k1lab. A brand new, deliberately INSECURE Python library for prototyping, experimenting, and BIP specs. It’s not for manufacturing use (as a result of it’s not constant-time and due to this fact susceptible to side-channel assaults), nevertheless it fills a vital hole: it affords a clear, constant reference for secp256k1 performance, together with BIP-340-style Schnorr signatures, ECDH, and low-level discipline/group arithmetic. The objective is easy: make it simpler and safer to write down future BIPs by avoiding redundant, one-off implementations. For BIP authors, this implies: much less customized code, fewer spec points, and a clearer path from prototype to proposal.
> Why Not Simply Use the Actual secp256k1 Library?
Bitcoin Core already features a quick, constant-time C library for secp256k1 cryptography. So why don’t BIP authors simply use that?
When a BIP writer submits a proposal, they’re anticipated to incorporate a reference implementation to clarify how the concept works. These implementations would not have to be written in Python, however C is usually too low-level for prototyping. Python is simpler to learn, simpler to change, and makes it clearer what the writer is making an attempt to precise. These qualities make it particularly well-suited for writing specs.
When introducing a brand new cryptographic thought, it helps to have one thing clear, concise, and protected to experiment with. In precept, instruments like hacspec are a very good choice for formal specs, since hacspec code can be legitimate Rust. However in apply, hacspec may be tough to work with and skim, particularly for BIP readers who are usually not acquainted with Rust.
Python’s readability continues to make it the language many authors return to when they should clarify how one thing works.
Why BIP Authors Maintain re-Rolling secp256k1 Once more and Once more
This began again with BIP 340 Schnorr Signatures, when the BIP authors wrote the unique reference code in Python so it could be simple to observe the mathematics. They outlined precisely how you can do Schnorr-style signing and verification utilizing secp256k1’s curve parameters. They needed to construct every part from scratch: discipline arithmetic, group operations, deterministic nonce era, and the encoding guidelines. The Python code was clear and academic. However it was tailor-made particularly to this single BIP, and never designed to be reused by future ones.
Equally, BIP 324 Encrypted P2P Transport, added encryption to how Bitcoin nodes ought to discuss to one another, and used a protocol known as Noise that depends on key exchanges, shared secrets and techniques, and symmetric encryption. Whereas it builds on the identical secp256k1 curve utilized in BIP 340, it didn’t reuse any of the particular implementation code. All the cryptographic logic similar to ECDH, serialization, and handshake patterns was re-implemented from scratch in Python. Despite the fact that the underlying math is identical, every BIP finally ends up writing its personal model of the logic. This results in duplicated effort and introduces the potential for delicate inconsistencies.
What secp256k1lab Truly Is
secp256k1lab is a Python library constructed for one goal: making it simpler to write down and take a look at cryptographic specs for Bitcoin. Python is already the preferred and broadly used language for reference implementations and take a look at vectors in BIPs, so having a shared, reusable library simply is smart. It’s not designed for manufacturing use. It’s constructed for prototyping, not efficiency. It affords a clear, unified interface to core secp256k1 performance, with readable code and minimal setup. No extra rolling your personal each time you need to take a look at an thought or exhibit how one thing ought to work.
Actual-World Use Case: ChillDKG
secp256k1lab was first developed as a part of the work on ChillDKG, a brand new BIP proposal for distributed key era. As a substitute of writing one more customized Python implementation of secp256k1 only for this one spec, the authors used secp256k1lab to deal with all of the cryptographic constructing blocks in a manner that it may very well be leveraged by others. By reusing a shared, readable codebase, their hope is that future cryptographic BIPs received’t have to start out from scratch. With secp256k1lab, there’s lastly a basis that new proposals can construct on and enhance collectively.
The place It May Go
There’s nonetheless an open query: ought to secp256k1lab dwell within the BIPs repository? It’s already proving helpful as a shared reference for cryptographic proposals, however there’s ongoing dialogue about the place it actually belongs inside the broader Bitcoin improvement course of. Whether or not it stays as a standalone library or turns into extra tightly built-in with the BIP workflow, one factor is obvious—it fills a niche that’s been round for years. When you’re a BIP writer, spec reviewer, or simply interested by bettering the cryptographic tooling round Bitcoin, we’d love your enter. You may be a part of the dialogue on the Bitcoin-Dev mailing record or contribute on to the secp256k1lab GitHub repo.
It is a visitor put up by Kiara Bickers. Opinions expressed are fully their very own and don’t essentially mirror these of BTC Inc or Bitcoin Journal.
