Trusted Machine Learning Models Unlock Private Inference for Problems
  Currently Infeasible with Cryptography
Authors: name: Ilia Shumailov, name: Daniel Ramage, name: Sarah Meiklejohn, name: Peter Kairouz, name: Florian Hartmann, name: Borja Balle, name: Eugene Bagdasarian

We often interact with untrusted parties. Prioritization of privacy can limit
the effectiveness of these interactions, as achieving certain goals
necessitates sharing private data. Traditionally, addressing this challenge has
involved either seeking trusted intermediaries or constructing cryptographic
protocols that restrict how much data is revealed, such as multi-party
computations or zero-knowledge proofs. While significant advances have been
made in scaling cryptographic approaches, they remain limited in terms of the
size and complexity of applications they can be used for. In this paper, we
argue that capable machine learning models can fulfill the role of a trusted
third party, thus enabling secure computations for applications that were
previously infeasible. In particular, we describe Trusted Capable Model
Environments (TCMEs) as an alternative approach for scaling secure computation,
where capable machine learning model(s) interact under input/output
constraints, with explicit information flow control and explicit statelessness.
This approach aims to achieve a balance between privacy and computational
efficiency, enabling private inference where classical cryptographic solutions
are currently infeasible. We describe a number of use cases that are enabled by
TCME, and show that even some simple classic cryptographic problems can already
be solved with TCME. Finally, we outline current limitations and discuss the
path forward in implementing them.