 
Summary: On Hiding Information from an Oracle \Lambda
Mart'in Abadi y
DEC Systems Research Center
130 Lytton Avenue
Palo Alto, CA 94301
Joan Feigenbaum z
AT&T Bell Laboratories
600 Mountain Avenue
Murray Hill, NJ 07974
Joe Kilian x
MIT
545 Technology Square
Cambridge, MA 02139
Abstract: We consider the problem of computing with encrypted data. Player A wishes to
know the value f(x) for some x but lacks the power to compute it. Player B has the power
to compute f and is willing to send f(y) to A if she sends him y, for any y. Informally, an
encryption scheme for the problem f is a method by which A, using her inferior resources,
can transform the cleartext instance x into an encrypted instance y, obtain f(y) from B,
and infer f(x) from f(y) in such a way that B cannot infer x from y. When such an
encryption scheme exists, we say that f is encryptable.
