Authentication and Trust Verification

HTTP provides no mechanism for verifying the authenticity of the server you're connecting to. When you visit an HTTP website, you have no cryptographic assurance that you're communicating with the intended server rather than an attacker performing a man-in-the-middle attack. This vulnerability enables phishing attacks, DNS hijacking, and other impersonation techniques that can redirect users to malicious sites while appearing legitimate.

HTTPS addresses this vulnerability through digital certificates and the public key infrastructure (PKI). When connecting to an HTTPS site, the server presents a digital certificate that has been signed by a trusted Certificate Authority (CA). Your browser verifies this certificate, checking that it's valid, hasn't expired, matches the domain you're visiting, and was issued by a CA in the browser's trust store. This verification process provides strong assurance that you're communicating with the legitimate server.

The certificate verification process in HTTPS also enables different levels of validation. Domain Validated (DV) certificates verify only domain ownership, while Organization Validated (OV) and Extended Validation (EV) certificates require increasingly rigorous identity verification. These different validation levels provide users with varying degrees of confidence about the entity operating the website, particularly important for e-commerce and financial services where trust directly impacts user behavior.