Before a receiver can authenticate messages with TESLA, it needs to be loosely time synchronized with the sender, know the disclosure schedule of keys, and receive an authenticated key of the one-way key chain.
Various approaches exist for time synchronization [24, 37, 22]. TESLA, however, only requires loose time synchronization between the sender and the receivers, so a simple algorithm is sufficient. The time synchronization property that TESLA requires is that each receiver can place an upper bound of the sender's local time, as we discuss in Section 2.2.
The sender sends the key disclosure schedule by transmitting the following information to the receivers over an authenticated channel (either via a digitally signed broadcast message, or over unicast with each receiver):