Browser-based ECH demo — draft-ietf-tls-esni. TLS 1.3 protects every byte except the hostname it announces first. Real HPKE seals the ClientHelloInner; a network observer sees only the outer. Tamper the ECHConfig and watch the real open fail. Metadata is the leak encryption doesn't close. No backends. No simulated math.

Browser-based downgrade demo — RFC 8446. Strip X25519MLKEM768 from the ClientHello and watch two PQ-capable endpoints agree on bare X25519. Success is the alarm. Negotiation happens before authentication — the fix isn't detection, it's binding the transcript into the key. FREAK and Logjam were this shape. No backends.

Browser-based TLS 1.3 handshake walkthrough — step through X25519 key exchange, Ed25519 auth, the HKDF key schedule, and AES-GCM records, with a MITM attack that gets blocked. Real WebCrypto. No backend.

Análise prática comparando DNS tradicional (UDP/53) e DNS over HTTPS (DoH) no Firefox. Capturas realizadas com tcpdump e analisadas no Wireshark para visualizar diferenças de tráfego, privacidade e comportamento do TLS. Inclui consultas com nslookup, análise de SNI e documentação visual com 16 imagens.

TLS 1.3 (RFC 8446) sans-IO state machine in pure Standard ML, verified against RFC 8448 vectors. Experimental, not for production security.