Editing Encrypted function

An '''encrypted function''' is an attempt to provide [[mobile code]] privacy without providing any [[tamper-resistance|tamper-resistant]] hardware. It is a method where in mobile code can carry out [[cryptography|cryptographic]] primitives. 

[[polynomial function|Polynomial]] and [[rational function]]s are [[encrypted]] such that their transformation can again be implemented, as programs consisting of [[cleartext]] instructions that a [[central processing unit|processor]] or [[interpreter (computing)|interpreter]] understands. The processor would not understand the program's function. This field of study is gaining popularity as mobile cryptography.

==Example==

Scenario: 
Host A, has an [[algorithm]] which computes function f. A wants to send its [[mobile agent]] to B which holds input x, to compute f(x). But A doesn't want B to learn anything about f.

Scheme:
Function f is encrypted in a way that results in E(f). Host A then creates another program P(E(f)), which implements E(f), and sends it to B through its agent. B then runs the agent, which computes P(E(f))(x) and returns the result to A. A then decrypts this to get f(x).

Drawbacks:
Finding appropriate encryption schemes that can transform arbitrary functions is a challenge. The scheme doesn't prevent [[denial of service]], replay, [[experimental extraction]] and others.

== See also ==

* [[Homomorphic encryption]]

==References==

* Thomas Sander and Christian F. Tschudin. ''Protecting Mobile Agents Against Malicious Hosts.'' In G. Vigna, editor, Mobile agents and security, volume 1419 of Lecture Notes in Computer Science, pages 44–60. Springer-Verlag, New York, NY, 1998. [http://citeseer.ist.psu.edu/cache/papers/cs/16015/http:zSzzSzwww.icsi.berkeley.eduzSz~tschudinzSzpszSzma-security.pdf/sander98protecting.pdf]

[[Category:Cryptography]]


{{comp-sci-stub}}