cbatsch

Location: Kyoto, Japan Remote: Yes. Working hours are flexible, overlap with US business hours is available. Willing to relocate: No Technologies: Swift/SwiftUI, Kotlin, C#/.NET 8, .NET MAUI, ASP.NET Core, TypeScript/Node.js, PostgreSQL; applied cryptography (ML-KEM, ML-DSA, AES-256-GCM, MLS/RFC 9420), FIDO2/WebAuthn passkeys, OpenID Connect, JWT Résumé/CV: on request by email Email: [email protected]

Senior engineer with more than 15 years of professional experience, available now for contract work, full-time or part-time. Small jobs are welcome.

I build and ship mobile and backend software where security matters. My own iOS apps are in the App Store (https://apps.apple.com/app/id6755644278 and https://apps.apple.com/app/id6748547975). I wrote the SaQura cryptography libraries for .NET, Kotlin, Swift, TypeScript and Python, published on NuGet, Maven Central, npm and PyPI, so the code is there to read: https://github.com/KyotoTechLLC/saqura-samples

Typical work: an iOS or Android release that is stuck on signing or store review; a .NET MAUI or Xamarin app that needs repair; passkey and token-based login done properly; end-to-end encryption; a prototype that has to become a product.

Earlier projects include a secure messenger platform for forensic medicine and a cross-platform app for ground operations at a major German airport. I invoice as a contractor and provide the W-8 form.