Xinshu Ma (University of Edinburgh), Michio Honda (University of Edinburgh)
Quantum computers threaten to break the cryptographic foundations of classical TLS, prompting a shift to post-quantum cryptography. However, post-quantum authentication imposes significant performance overheads, particularly for mutual TLS in cloud environments with high handshake rates. We present Looma, a fast post-quantum authentication architecture that splits authentication into a fast, on-path sign/verify operation and slow, off-path pre-computations performed asynchronously, reducing handshake latency without sacrificing security. Integrated into TLS 1.3, Looma lowers PQTLS handshake latency by up to 44% compared to a Dilithium-2--based baseline. Our results demonstrate the practicality of Looma for scaling post-quantum secure communications in cloud environments.