Alice Call Placement Service Bob -------------------------------------------------------------------- Store Encrypted PASSporT for 2.222.555.2222 -> Call from 1.111.555.1111 ------------------------------------------> <-------------- Request PASSporT(s) for 2.222.555.2222 Obtain Encrypted PASSporT --------> (2.222.555.2222, 1.111.555.1111) [Ring phone with verified callerid = 1.111.555.1111]