Authors: Michael Hicks (UMD), Andrew Miller (UCF), Jon Katz (UMD), and Elaine Shi (UMD). Title: Authenticated Data structures, Generically Abstract: An authenticated data structure (ADS) is a data structure whose operations can be carried out by an untrusted server, the results of which a client can efficiently verify as authentic. This is normally done by having the server produce a compact "verification object" along with a query result that the client uses to check the result. ADSs thus support outsourcing data maintenance and processing tasks to untrusted servers without loss of authenticity. Past work on ADSs has focused on developing particular data structures, or limited classes of data structures, one at a time, often with support only for particular operations, e.g., particular types of queries. In this short talk I will present work-in-progress on a method that manifests as a small extension to a ML-like functional programming language and which supports general-purpose authenticated computation. We can support authenticated operations over data structures constructed from standard type constructors, including recursive types, sums, products, base types, and polymorphic types, programmed using standard language constructs. Using our approach, one can trivially produce authenticated versions of many interesting data structures, including binary search trees, red-black trees, and skip lists; we are working on developing recursive separator tree for a planar graph, to support efficient (authenticated) shortest path queries.