*15:17*[Pub][ePrint] How to Use Indistinguishability Obfuscation: Deniable Encryption, and More, by Amit Sahai and Brent Waters

We introduce a new technique, that we call punctured programs,

to apply indistinguishability obfuscation towards cryptographic

problems. We use this technique to carry out a systematic study of

the applicability of indistinguishability obfuscation to a variety of

cryptographic goals. Along the way, we resolve the 16-year-old open

question of Deniable Encryption, posed by Canetti, Dwork, Naor,

and Ostrovsky in 1997: In deniable encryption, a sender who is forced

to reveal to an adversary both her message and the randomness she used

for encrypting it should be able to convincingly provide ``fake\'\'

randomness that can explain any alternative message that she would

like to pretend that she sent. We resolve this question by giving the

first construction of deniable encryption that does not require

any pre-planning by the party that must later issue a denial.

In addition, we show the generality of our punctured programs

technique by also constructing a variety of core cryptographic objects

from indistinguishability obfuscation and one-way functions (or close

variants). In particular we obtain: public key encryption, short

``hash-and-sign\'\' selectively secure signatures, chosen-ciphertext

secure public key encryption, non-interactive zero knowledge proofs

(NIZKs), injective trapdoor functions, and oblivious transfer. These

results suggest the possibility of indistinguishability

obfuscation becoming a ``central hub\'\' for cryptography.