Information dispersal addresses the question of storing a ?le by distributing it among a set of servers in a storageef ?cient way. We introduce the problem of veri?able information dispersal in an asynchronous network, where up to one third of the servers as well as an arbitrary number of clients might exhibit Byzantine faults. Veri?ability ensures that the stored information is consistent despite such faults. We present a storage- and communication-ef?cient scheme for asynchronous veri?able information dispersal that achieves an asymptotically optimal storage blow-up. Additionally, we show how to guarantee the secrecy of the stored data with respect to an adversary that may mount adaptive attacks. Our technique also yields a new protocol for asynchronous reliable broadcast that improves the communication complexity by an order of magnitude on large inputs.