Researcher: Adrian Perrig
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.