Sebastien Rousseau
Black and White Portrait of Sebastien Rousseau

Sebastien Rousseau

Shaping the future of banking
through AI, payments,
and quantum-safe security.

Applying AI and quantum-safe security to the future of payments.

Authored & maintained

Open source for the
future of finance.

A portfolio of Python, Rust and JavaScript libraries I created and maintain. Open source, free to use, and applied to wholesale payments, cross-border settlement, financial data and quantum-resistant cryptography.

pain001 logo. Open-source ISO 20022 payment file automation by Sebastien Rousseau
Python · Payments

pain001

A Python library that automates ISO 20022 pain.001 payment file creation from CSV or SQLite. Built for the global migration from MT/MX to structured messages across SWIFT, SEPA and major schemes.

Learn about pain001
pacs008 logo. Open-source ISO 20022 pacs.008 toolkit by Sebastien Rousseau
Python · Cross-border

pacs008

Generate, validate and deliver ISO 20022 pacs.008 FI-to-FI customer credit transfer messages. JSON Schema, XSD validation, IBAN across 75 countries, GDPR/PCI-DSS-compliant PII masking.

Learn about pacs008
Bank Statement Parser logo. Open-source finance toolkit by Sebastien Rousseau
Python · Finance

Bank Statement Parser

A finance-grade Python toolkit that turns multi-format bank statements into structured data. Designed for the realities of real-world statement files and the audit demands of regulated environments.

Learn about Bank Statement Parser
Hash HSH logo. Open-source Rust hash library by Sebastien Rousseau
Rust · Security

Hash (HSH)

A Rust library implementing secure hash and digest algorithms for password encryption and verification. Designed with a quantum-resistant posture for the post-PQC era of authentication.

Learn about HSH
KyberLib logo. Open-source Rust CRYSTALS-Kyber library by Sebastien Rousseau
Rust · Quantum

KyberLib

A robust Rust implementation of CRYSTALS-Kyber, the NIST FIPS 203 standard for general-purpose post-quantum encryption. The foundation for quantum-resistant payment authentication.

Learn about KyberLib
noyalib logo. Open-source pure-Rust YAML 1.2 ecosystem by Sebastien Rousseau
Rust · YAML

noyalib

A pure-Rust YAML 1.2 ecosystem. Zero unsafe, 100% spec compliance (406 / 406 official suite), streaming-first serde, lossless CST and JSON-Schema validation. Library + CLI (noyafmt, noyavalidate) + LSP + MCP + WASM bindings.

Learn about noyalib

“Quantum computing threatens the cryptographic foundations of financial services. Payments, from real-time to cross-border settlement, rely on protections that quantum computing will eventually render obsolete.”

Emerging Payments Association Asia (EPAA) · September 2025

Quantum-Safe Payments.

Industry white paper for the Emerging Payments Association Asia. The structural threat quantum computing poses to payment infrastructure, and the case for coordinated action now.

Banner illustration for the EPAA Quantum-Safe Payments white paper

EPAA · September 2025

Why the payments industry must act now.

Regulators are treating harvest-now-decrypt-later as a credible present risk. This paper outlines the structural threat and the urgent case for coordinated action across wholesale payment rails.

Read the white paper

Latest

From the desk.

Recent research and writing on quantum-safe cryptography, ISO 20022 migration and the future of wholesale payments.

Quantum computing circuit board with blue light patterns
Quantum

Quantum Thresholds Are Moving Again

A new paper suggests Shor's algorithm could run on as few as 10,000 qubits. The threshold for cryptographically relevant quantum computing is dropping fast.

Experience

Brands along the way.

From global Tier-1 banks to consumer technology. Payments and digital product leadership across HSBC, PayPal, Barclays, Shazam, AKQA and Virgin Group.