JWT, OAuth 2.1 & OpenID Connect (OIDC) — Principal Architecture Deep Dive
Under-the-hood engineering guide to JOSE (JWS/JWE/JWKS), OAuth 2.0 vs OAuth 2.1, PKCE S256 cryptography, OpenID Connect ID Token mechanics, Phantom Token pattern, DPoP (RFC 9449), Token Exchange (RFC 8693), and Senior/Staff interview playbooks.
Payment Security: Securing Client Ingress & Internal Core Banking
Enterprise engineering guide to securing payment processing systems — client-side mTLS, RFC 9421 HTTP message signatures, DPoP token binding, PSD2 dynamic linking, internal Zero Trust SPIFFE mesh, PCI-HSMs, tokenization vaults, and Maker-Checker dual control.
