The TESLA Broadcast Authentication Protocol

TLDR

Source authentication in broadcast communication is challenging due to untrusted receivers, unreliable channels, and the absence of retransmissions. The paper introduces the TESLA broadcast authentication protocol, aiming to provide efficient, low‑overhead, loss‑tolerant authentication that scales to many receivers, and explores its use in a PKI application. TESLA achieves its goals by relying on loose time synchronization between sender and receivers, enabling efficient MAC‑based authentication without retransmissions. Using only symmetric MAC functions, TESLA attains asymmetric authentication properties, demonstrating its effectiveness in broadcast scenarios.

Abstract

One of the main challenges of securing broadcast communication is source authentication, or enabling receivers of broadcast data to verify that the received data really originates from the claimed source and was not modified en route. This problem is complicated by mutually untrusted receivers and unreliable communication environments where the sender does not retransmit lost packets. This article presents the TESLA (Timed Efficient Stream Loss-tolerant Authentication) broadcast authentication protocol, an efficient protocol with low communication and computation overhead, which scales to large numbers of receivers, and tolerates packet loss. TESLA is based on loose time synchronization between the sender and the receivers. Despite using purely symmetric cryptographic functions (MAC functions), TESLA achieves asymmetric properties. We discuss a PKI application based purely on TESLA, assuming that all network nodes are loosely time synchronized.