IACR News item: 16 July 2015
Jesper Buus Nielsen, Samuel Ranellucci
ePrint Reportthings
for the construction of two and three-party secure computation, private
function evaluation and secure outsourcing. Garbling schemes is a primitive
which formalizes the syntax and security properties of garbled circuits.
We define a generalization of garbling schemes called \\emph{reactive garbling
schemes}.
We consider functions and garbled functions taking multiple inputs and giving
multiple outputs.
Two garbled functions can be linked together:
an encoded output of one garbled function can be transformed
into an encoded input of the other garbled function without communication
between the parties.
Reactive garbling schemes also allow partial evaluation of garbled functions
even when only some of the encoded inputs are provided.
It is possible to further evaluate the linked garbled functions
when more garbled inputs become available.
It is also possible to later garble more functions and link them to the
ongoing garbled evaluation.
We provide rigorous definitions for reactive garbling schemes.
We define a new notion of security for reactive garbling schemes called
confidentiality.
We provide both simulation based and indistinguishability based notions of
security.
We also show that the simulation based notion of security
implies the indistinguishability based notion of security.
We present an instantiation of reactive garbling schemes. We present an
application of reactive garbling schemes to reactive
two-party computation secure against a malicious adversary. We demonstrate
how garbling schemes can be used to give abstract black-box descriptions and
proof of several advanced applications of garbled circuits in the literature,
including Minilego
and Lindell\'s forge-and-loose technique.
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