The imminent advent of cryptographically relevant quantum computers necessitates a fundamental migration of the Internet’s cryptographic infrastructure. While hybrid key exchange mechanisms are approaching maturity, the transition of Transport Layer Security (TLS) authentication remains critically obstructed by the bandwidth constraints of post-quantum digital signatures. The direct substitution of classical digital signature primitives with lattice-based alternatives introduces multi-kilobyte certificate chains, precipitating severe latency penalties and fragmentation issues that threaten the scalability of the global ecosystem. This thesis introduces Practical Hybrid TLS (PH-TLS), a novel protocol architecture that resolves this authentication bottleneck by decoupling trust establishment from the handshake’s critical path. By integrating a verifiable Hybrid Key Transparency (HKT) infrastructure, PH-TLS eliminates the transmission of X.509 certificates, relying instead on compact Merkle inclusion proofs and KEM-based implicit authentication.