1 research outputs found
Simplifying Game-Based Definitions: Indistinguishability up to Correctness and Its Application to Stateful AE
Often the simplest way of specifying game-based cryptographic definitions
is apparently barred because the adversary would have some trivial win.
Disallowing or invalidating these wins can
lead to complex or unconvincing definitions.
We suggest a generic way around this difficulty.
We call it indistinguishability up to correctness, or IND|C.
Given games G and H
and a correctness condition C
we define an advantage measure Adv_{G,H,C}^indc wherein
G/H distinguishing attacks are effaced
to the extent that they are inevitable due to C.
We formalize this in the language of oracle silencing,
an alternative to exclusion-style and penalty-style definitions.
We apply our ideas to a domain where game-based definitions have
been cumbersome: stateful authenticated-encryption (sAE).
We rework existing sAE notions and encompass new ones,
like replay-free AE permitting a specified degree of out-of-order message delivery