When typed objects migrate in virtual memory, onto offine storage, or among the nodes of a network, the type managers must relinguish control over the object representation and state. In this paper we present a mechanism which allows a type manager to authenticate and reinstantiate migrated objects. This mechanism also solves some problems stemming from the hierarchical structure of the system itself. The mechanism is based on a combination of cryptographic techniques using (nondistributable) centralized, secret keys, and data redundancy which characterizes the object representation and state. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.