---
id: fastecdsa
version: "3.0.1"
license: This is free and unencumbered software released into the public domain. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a… (full text in the JSON record)
license_treatment: permissive
maintenance: active
---

# fastecdsa — Fast elliptic curve digital signatures

License: permissive · Maintenance: active · Downloads: 225.8K/mo

## What it is and what it does

fastecdsa is a Python wrapper around optimized C code for elliptic curve cryptography, specifically digital signatures. It supports NIST curves (P192, P224, P256, P384, P521), Certicom secp curves including secp256k1 (Bitcoin's curve), and Brainpool curves, plus arbitrary Weierstrass-form curves. The library prioritizes constant-time operations to resist timing side-channel attacks, uses RFC6979 for deterministic nonce generation, and validates all points before operating on them.

The package is designed for developers who need fast ECDSA operations and can manage the system-level dependency on GMP. It has no Python runtime dependencies and supports Python 3.9 through 3.13 on Linux and macOS. The author explicitly recommends using more established libraries for security-critical applications, positioning this as a performant option for applications where speed matters and the risk profile is acceptable.

Use it for:

- Signing and verifying blockchain transactions where secp256k1 performance is critical.
- Generating and validating digital signatures in high-throughput authentication systems.
- Prototyping or benchmarking elliptic curve cryptography implementations.
- Building cryptographic protocols that require specific NIST or Brainpool curves.
- Educational exploration of constant-time ECC arithmetic and nonce-safe ECDSA.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides fast elliptic curve digital signature operations (signing and verification) using NIST and Certicom curves, with no nonce reuse and constant-time point multiplication to mitigate timing attacks.

Yes, if you need fast ECDSA operations and can install GMP on Linux or macOS. The library is actively maintained, has no known vulnerabilities, and offers significant performance gains over pure-Python alternatives. However, the author cautions against using it for security-critical applications without additional review—use an audited library like libsodium or cryptography for production security-sensitive code. The Windows limitation and system dependency on GMP are real friction points.

## Install

pip install fastecdsa
uv add fastecdsa
poetry add fastecdsa

## Installing fastecdsa

Before you install: Medium friction: requires a C compiler and the GMP library (libgmp3-dev on Linux, installable via brew on macOS). Prebuilt wheels are available for Python 3.9–3.13 on Linux and macOS x86_64 and ARM64, but Windows is not officially supported. Active maintenance as of April 2026.

License in practice: Released into the public domain under CC0 1.0 (Unlicense). No restrictions on use, modification, or distribution for any purpose, commercial or otherwise.

Quickstart:

pip install fastecdsa

from fastecdsa.curve import P256
from fastecdsa.keys import gen_keypair

private_key, public_key = gen_keypair(P256)
from fastecdsa import sign, verify
signature = sign('message', private_key, curve=P256)
verify(signature, 'message', public_key, curve=P256)

Requires GMP library installed on system (apt-get install libgmp3-dev on Linux, brew install gmp on macOS). Windows is not officially supported.

Verify before relying:

- Whether the library has undergone independent security audit or formal verification beyond the author's own review.
- Current status of the performance comparison with ecdsa package (benchmarks in docs are from early 2014 MacBook Air).
- Whether custom curve construction validation has been improved since the initial warning against using them for security-critical applications.

## Package facts

- License: This is free and unencumbered software released into the public domain. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a… (full text in the JSON record) (permissive)
- Python support: supports_current
- Install friction: medium
- Maintenance: active
- Downloads: 225.8K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

elliptic curve cryptography, ecdsa digital signatures, fast ecc signing, nonce-safe ecdsa, constant-time point multiplication, P256 P384 P521 curves, secp256k1 bitcoin curve, constant-time, nonce-safe, performance-focused

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