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Critical riskScanned 2026-05-29

python-ecdsa — Post-Quantum Cryptography Analysis

tlsfuzzer/python-ecdsa ↗|Python|48 files scanned|38 vulnerable

python-ecdsa is a pure-Python ECDSA implementation with 36 million PyPI downloads per month. The library implements the exact algorithm that Shor's quantum attack targets — ECDSA over NIST curves (P-192, P-224, P-256, P-384, P-521) and Brainpool curves. Every signing operation, every key pair, and every verification in 36M monthly downloads is quantum-vulnerable. Scored 95/100: the highest-risk library in our corpus of famous repos.

95
/ 100 risk score
Critical risk
Critical findings2
High findings2
Medium findings0
Low findings0

Findings

criticalECDSA P-256 / P-384 / P-521
ecdsa/keys.py

Core library functionality. 171 ECDSA patterns detected. Every signing key is breakable by Shor's algorithm.

PQC →ML-DSA-44 (128-bit PQ security), ML-DSA-65 (192-bit). Drop-in replacement API possible.
criticalNIST P-192 (deprecated)
ecdsa/ecdsa.py

P-192 was deprecated by NIST in 2015. Broken by classical attacks, trivially broken by quantum.

PQC →Migrate immediately to ML-DSA regardless of quantum timeline.
highBrainpool curves (BP-256 / BP-384 / BP-512)
ecdsa/ecdsa.py

European alternative curves. Same discrete-log assumption — quantum-vulnerable identical to NIST curves.

PQC →ML-DSA-65 for equivalent security level.
highRFC 6979 deterministic k generation
ecdsa/rfc6979.py

Correct classical implementation but doesn't add quantum resistance. Fault attacks possible with ECDSA regardless.

PQC →ML-DSA uses deterministic signing natively without this risk.

Compliance note

Any Python project importing `from ecdsa import SigningKey` is using quantum-vulnerable cryptography. At 36M downloads/month, python-ecdsa is one of the most widely deployed quantum risks in the Python ecosystem. pip install cryptography && migrate to ml_dsa is the practical migration path.

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