SSL/TLS

SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are cryptographic protocols that encrypt data transmitted between a client and a server. When you see a padlock icon in your browser or a URL beginning with https://, TLS is at work, ensuring that no intermediary can read or tamper with the traffic.

Why It Matters

Every AI assistant deployment handles sensitive data: API keys, user messages, model responses, and authentication tokens. Without TLS, this information travels across the internet in plaintext, vulnerable to eavesdropping and man-in-the-middle attacks. Modern platforms like Railway, Vercel, and AWS automatically provision TLS certificates for public endpoints, but understanding the protocol helps you troubleshoot certificate errors and configure custom domains correctly.

How It Works

TLS operates through a handshake process. When a client connects, the server presents a digital certificate signed by a trusted Certificate Authority (CA). The client verifies the certificate, and both parties negotiate a shared encryption key using asymmetric cryptography. All subsequent data flows through a symmetric cipher, providing both confidentiality and integrity.

In a typical reverse-proxy architecture, TLS terminates at the proxy layer. The proxy decrypts incoming HTTPS requests, forwards them as plain HTTP to internal services like an AI gateway on localhost, and encrypts responses before sending them back. This pattern, called TLS termination, simplifies certificate management because only the edge proxy needs a certificate.

In Practice

When deploying an AI assistant behind a reverse proxy, ensure that your proxy sets the X-Forwarded-Proto header so backend services know the original request was encrypted. Always redirect HTTP traffic to HTTPS, and use HSTS headers to prevent protocol downgrade attacks.