Senior Mobile Security Engineer - Passkey & AI-Driven Auth

United States Digital Space LLC; Hong Kong; On-site; HKD 900,000 - 1,300,000; Full time

Job summary

United States Digital Space LLC is seeking a Staff Mobile Platform engineer to own account security and authentication subsystems for iOS and Android. You will shape secure flows, collaborate with risk and security teams, and drive automation in engineering workflows.

Strong background in native mobile development, Rust with UniFFI, and experience with Passkey/WebAuthn is highly valued. Apply your AI expertise to improve delivery quality and reliability.

Qualifications

• Experience building native iOS and/or Android apps.
• Cross‑platform or shared‑logic architecture experience.
• Strong knowledge of Rust and UniFFI.
• Hands‑on security in mobile auth: OAuth/OIDC, MFA, Passkey / WebAuthn.
• Proficiency with Swift, Kotlin, or other major mobile languages.

Responsibilities

• Own account subsystem design and security across iOS/Android platforms.
• Design secure, low‑friction login and authentication flows at scale.
• Collaborate with risk & security for threat models and defenses.
• Build AI‑native engineering practices for automated development workflows.
• Lead code reviews and raise engineering quality across teams.
• Set technical direction beyond your subsystem and influence cross‑team decisions.

Skills

iOS/Android native

Cross‑platform knowledge

Rust

UniFFI

Swift

Kotlin

React Native

Flutter

Security fundamentals

OAuth/OIDC

MFA

WebAuthn

Keychain/Keystore

Passkey

Java

JavaScript

Tools

UniFFI

Keychain/Keystore

WebAuthn

Job description

United States Digital Space LLC is seeking a Staff Mobile Platform engineer to own account security and authentication subsystems for iOS and Android. You will shape secure flows, collaborate with risk and security teams, and drive automation in engineering workflows.

Strong background in native mobile development, Rust with UniFFI, and experience with Passkey/WebAuthn is highly valued. Apply your AI expertise to improve delivery quality and reliability.