HTTPS (HTTP Secure) is HTTP layered over TLS/SSL encryption, transforming the web from a plaintext protocol into one that protects confidentiality, integrity, and authenticity of data in transit. Where HTTP sends data naked across the network, HTTPS wraps every byte in cryptographic armor — yet this protection is not automatic. It requires certificates, key exchanges, handshakes, and trust chains working in concert. Understanding HTTPS means understanding how servers prove their identity, how encryption keys are negotiated, and how the entire ecosystem prevents eavesdropping, tampering, and impersonation. A critical reality: HTTPS protects data in transit, but only if certificates are valid, TLS is properly configured, and both endpoints are trustworthy — otherwise, you have encrypted communication with the wrong party.