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Random-Oracle Uninstantiability from Indistinguishability Obfuscation [chapter]

Christina Brzuska, Pooya Farshim, Arno Mittelbach
2015 Lecture Notes in Computer Science  
Assuming the existence of indistinguishability obfuscation (iO), we show that a number of prominent transformations in the random-oracle model are uninstantiable in the standard model.  ...  Our results call for a re-assessment of scheme design in the random-oracle model and highlight the need for new transforms that do not suffer from iO-based attacks.  ...  Such an obfuscation is, however, heavily structured and it is not clear if indistinguishability obfuscation schemes exist that have an obfuscation which is indistinguishable from a uniformly random bit  ... 
doi:10.1007/978-3-662-46497-7_17 fatcat:x4kztrpkyrgm7clzws2z26oic4

A Unified Approach to Idealized Model Separations via Indistinguishability Obfuscation [chapter]

Matthew D. Green, Jonathan Katz, Alex J. Malozemoff, Hong-Sheng Zhou
2016 Lecture Notes in Computer Science  
In this work we refute this possibility, assuming the existence of indistinguishability obfuscation. We do so in the following way.  ...  First, we present a random oracle separation for bitencryption; namely, we show that there exists a bit-encryption protocol secure in the random oracle model but completely insecure when the random oracle  ...  Finally, a recent line of work constructs schemes which use both indistinguishability obfuscation and the random oracle model [26, 27, 18] .  ... 
doi:10.1007/978-3-319-44618-9_31 fatcat:4hh3ho73hnfb7gyjmc4fbgjye4

Indistinguishability Obfuscation and UCEs: The Case of Computationally Unpredictable Sources [chapter]

Christina Brzuska, Pooya Farshim, Arno Mittelbach
2014 Lecture Notes in Computer Science  
oracles in a number of prominent applications, including all those mentioned above, without suffering from the aforementioned uninstantiability result.  ...  However, due to an uninstantiability result of Canetti, Goldreich, and Halevi (STOC 1998) random oracles have become somewhat controversial.  ...  When S interacts with a random oracle, y coincides with H.Ev(1 λ , hk, x) with probability 2 −H.ol(λ) . Now let iO be an indistinguishability obfuscator.  ... 
doi:10.1007/978-3-662-44371-2_11 fatcat:r3cxk4frozaodgqx3mkw4r7lsy

On the Correlation Intractability of Obfuscated Pseudorandom Functions [chapter]

Ran Canetti, Yilei Chen, Leonid Reyzin
2015 Lecture Notes in Computer Science  
This observation was used in [CGH04] to demonstrate the uninstantiability of the random oracle model [BR93] .  ...  We assume the existence of sub-exponentially secure indistinguishability obfuscators, puncturable pseudorandom functions, and input-hiding obfuscators for evasive circuits.  ...  Alternative approaches to instantiating random oracles. Several alternative definitions have been proposed in order to capture the random-oracle-like properties.  ... 
doi:10.1007/978-3-662-49096-9_17 fatcat:abjanoqpvbevdmufe3ccqwhcja

Indistinguishability Obfuscation versus Multi-bit Point Obfuscation with Auxiliary Input [chapter]

Christina Brzuska, Arno Mittelbach
2014 Lecture Notes in Computer Science  
Towards this goal, we build on techniques by Brzuska, Farshim and Mittelbach (Crypto 2014) who use indistinguishability obfuscation as a mean to attack a large class of assumptions from the Universal Computational  ...  We show that if indistinguishability obfuscation exists, then MB-AIPO does not.  ...  A random oracle uninstantiability. Lynn et al.  ... 
doi:10.1007/978-3-662-45608-8_8 fatcat:b6u6guuiz5f5zarmxgs2fvhqdu

Lockable Obfuscation

Rishab Goyal, Venkata Koppula, Brent Waters
2017 2017 IEEE 58th Annual Symposium on Foundations of Computer Science (FOCS)  
In a similar vein we provide random oracle uninstantiability results of the Fujisaki-Okamoto transformation (and related transformations) from the lockable obfuscation combined with fully homomorphic encryption  ...  The tool of lockable obfuscation allows these constructions to be almost immediately realized by translation from previous indistinguishability obfuscation based constructions.  ...  Uninstantiability of the Fujisaki-Okamoto and Related Transformations We now move to our second set of separation results where we use lockable obfuscation to show random oracle uninstantiability [CGH98  ... 
doi:10.1109/focs.2017.62 dblp:conf/focs/GoyalKW17 fatcat:vbaadqt3ofarpaynqwxhot5voe

Cryptographic Agents: Towards a Unified Theory of Computing on Encrypted Data [chapter]

Shashank Agrawal, Shweta Agrawal, Manoj Prabhakaran
2015 Lecture Notes in Computer Science  
Highlights of our framework include the following: • We use a new indistinguishability preserving (IND-PRE) definition of security that interpolates indistinguishability and simulation style definitions  ...  provide a new framework of cryptographic agents that unifies various modern "cryptographic objects" -identity-based encryption, fully-homomorphic encryption, functional encryption, and various forms of obfuscation  ...  Several works have shown that these oracles are "uninstantiable," and further there are uninstantiable primitives that can be implemented in the models with such oracles [62, 67, 66, 14, 63] .  ... 
doi:10.1007/978-3-662-46803-6_17 fatcat:jzsadxqa2feznkhgfaj3kyo6ny

Private Functional Encryption: Indistinguishability-Based Definitions and Constructions from Obfuscation [chapter]

Afonso Arriaga, Manuel Barbosa, Pooya Farshim
2016 Lecture Notes in Computer Science  
We develop a new indistinguishability-based privacy notion that overcomes these limitations and give constructions supporting different circuit classes and meeting varying degrees of security.  ...  Obfuscation is a common building block that these constructions share, albeit the obfuscators necessary for each construction are based on different assumptions.  ...  a fresh random value uniformly sampled from WSp λ .  ... 
doi:10.1007/978-3-319-49890-4_13 fatcat:wgiopvhqr5delfi4zo7g2qgi4q

Chosen Ciphertext Security via UCE [chapter]

Takahiro Matsuda, Goichiro Hanaoka
2014 Lecture Notes in Computer Science  
oracle model.  ...  As our negative results, we show difficulties of instantiating the random oracle in the Fujisaki-Okamoto (FO) construction (PKC'99) with a UCE, by exhibiting pairs of CPA secure PKE and a UCE for which  ...  The authors would like to thank Pooya Farshim for giving us a detailed overview of their attack [12] on UCE security using indistinguishability obfuscation.  ... 
doi:10.1007/978-3-642-54631-0_4 fatcat:m2opqcuys5c4xewszq2lynml3m

Quantum copy-protection of compute-and-compare programs in the quantum random oracle model [article]

Andrea Coladangelo, Christian Majenz, Alexander Poremba
2022 arXiv   pre-print
We prove that our scheme achieves non-trivial security against fully malicious adversaries in the quantum random oracle model (QROM), which makes it the first copy-protection scheme to enjoy any level  ...  3 (note that publishing H(v) for a random oracle H is an ideal obfuscator for the point function with marked input v).  ...  Crucially, x1 and x2 are not sampled uniformly at random, but from the distribution X λ which is statistically indistinguishable from the distribution of marked inputs from which y is sampled (by definition  ... 
arXiv:2009.13865v3 fatcat:xzf3rza7czfttapol2xcnspkga

Breaking the Sub-Exponential Barrier in Obfustopia [chapter]

Sanjam Garg, Omkant Pandey, Akshayaram Srinivasan, Mark Zhandry
2017 Lecture Notes in Computer Science  
Indistinguishability obfuscation (iO) has emerged as a surprisingly powerful notion.  ...  Almost all known cryptographic primitives can be constructed from general purpose iO and other minimalistic assumptions such as one-way functions.  ...  The latter definition requires random oracles, so it is unfortunately uninstantiable in the standard model.  ... 
doi:10.1007/978-3-319-56617-7_6 fatcat:ozsnk6fpt5e6lcb4ledcsiriii

Rate-1 Incompressible Encryption from Standard Assumptions [article]

Pedro Branco, Nico Döttling, Jesko Dujmovic
2022 IACR Cryptology ePrint Archive  
Guan et al. provided a low-rate instantiation of this notion from standard assumptions and a rate-1 instantiation from indistinguishability obfuscation (iO).  ...  Our construction can be realized from, e.g. the DDH and additionally the DCR or the LWE assumptions.  ...  Random Oracle Model In our constructions we use the ideal cipher model, which can be date back to Shannon [Sha49] and proven to be indifferentiable from the random oracle model [BR93, HKT11] .  ... 
dblp:journals/iacr/BrancoDD22 fatcat:pvjdrnoqsbehlefxkhchz6hx6m

Must You Know the Code of f to Securely Compute f? [chapter]

Mike Rosulek
2012 Lecture Notes in Computer Science  
The characterization is inspired by notions of autoreducibility from computational complexity theory.  ...  In other words, a secure protocol for evaluating f is typically obtained in a non-black-box-way from f itself.  ...  In the above, R is a random oracle; thus f s is a PRF. Indistinguishability holds due to the pseudorandomness of g, the fact that ⊕ is a group operation, and the pseudorandomness of f , respectively.  ... 
doi:10.1007/978-3-642-32009-5_7 fatcat:zbk7wnq4tfbtlkajqgfkz222qy

On the (In)security of Fischlin's Paradigm [chapter]

Prabhanjan Ananth, Raghav Bhaskar, Vipul Goyal, Vanishree Rao
2013 Lecture Notes in Computer Science  
oracle model) insecure in the standard model, thus showing that the random oracle is uninstantiable.  ...  However, this transformation is proven secure only in the random oracle model.  ...  from random).  ... 
doi:10.1007/978-3-642-36594-2_12 fatcat:kxwohkakmnfh5gf3ravve2jv4q

Modeling Random Oracles Under Unpredictable Queries [chapter]

Pooya Farshim, Arno Mittelbach
2016 Lecture Notes in Computer Science  
In recent work, Bellare, Hoang, and Keelveedhi (CRYPTO 2013) introduced a new abstraction called Universal Computational Extractors (UCEs), and showed how they can replace random oracles (ROs) across a  ...  This brings the first result closer to practice by moving away from variable-input-length ROs. Our security proofs employ techniques from indifferentiability in multi-stage settings.  ...  Behind UCEs lies a new way to model the indistinguishability of a keyed hash function from a random oracle.  ... 
doi:10.1007/978-3-662-52993-5_23 fatcat:wwoqkjlj3zgrhesxmnqnuidodq
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