Sebastien Rousseau

Senior Product Manager, Wholesale Payments & API · HSBC

Payments infrastructure banks can trust in the quantum era.

I lead wholesale payments API products at HSBC and build open-source ISO 20022 and post-quantum tooling that banks and fintechs can inspect, test and reuse.

EPAA white-paper contributor · Fellow, Institution of Analysts and Programmers

Black and White Portrait of Sebastien Rousseau

Payments and digital products, built at:

# 1. Validate ISO 20022 pacs.008.001.10 (pip install pacs008)
pacs008 -t pacs.008.001.10 -m template.xml -s schema.xsd -d payments.csv --dry-run
✓ Schema validation passed
✓ Data validation passed (1 payment records)

# 2. Verify NIST FIPS 203 ML-KEM-768 KEM (cargo add kyberlib)
cargo test -p kyberlib --test test_kem
✓ test keypair_encap_decap ... ok
✓ test result: ok. 9 passed; 0 failed; finished in 0.01s

# 3. Verify live CycloneDX SBOM provenance (SLSA / Sigstore)
curl -sSLO https://sebastienrousseau.com/sbom.cdx.json && gh attestation verify sbom.cdx.json --owner sebastienrousseau
✓ Loaded 1 attestation from GitHub API (slsa.dev/provenance/v1)
✓ Verification succeeded!
ISO 20022 · SWIFT CBPR+ NIST FIPS 203 (ML-KEM) CycloneDX 1.6 + Sigstore

What I build

Open-source foundations for wholesale finance.

Tooling

Audited Rust libraries and a code security scanner, signed and shipped with a software bill of materials.

View the tooling

Proof

By the numbers.

53.0M All-time downloads
3.7M Downloads, last 30 days
736 GitHub stars
179 Packages published

Most downloads come from transitive dependencies in CI/CD pipelines and production services across PyPI, crates.io, and npm · Updated .

Recognition

Recognition and featured work.

Isometric render of an illuminated processor, representing the cryptographic foundations of payments.

EPAA · September 2025

Why the payments industry must act now.

Regulators are treating harvest-now-decrypt-later as a credible present risk. This paper, produced for the Emerging Payments Association Asia, sets out the structural threat and the case for coordinated action across wholesale payment rails.

Read the white paper (PDF)

  • Fellow of the Institution of Analysts and Programmers (FIAP)
  • Mobile Agency of the Year
  • Agency of the Year
  • Best Branded Social TV Award
  • Best 2nd Screen Experience for TV on Mobile or Tablet (Shazam for TV)

Latest

From the desk.

City of London financial district architecture representing FCA outcomes-based AI regulation and UK financial services governance.
AI · AI Governance · Compliance

Why the FCA Is Regulating AI Without an AI Rulebook

TL;DR Why the FCA regulates AI through its existing principles-based, outcomes-focused rules rather than an AI rulebook, and where governance may need to adapt.

Working on payments, quantum-safety or ISO 20022?

Tell me what you are building. The typical first response is within 48 hours.

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