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Electronic Colloquium on Computational Complexity

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All reports by Author Hemanta Maji:

TR14-069 | 5th May 2014
Shashank Agrawal, Divya Gupta, Hemanta Maji, Omkant Pandey, Manoj Prabhakaran

Explicit Non-Malleable Codes Resistant to Permutations

The notion of non-malleable codes was introduced as a relaxation of standard error-correction and error-detection. Informally, a code is non-malleable if the message contained in a modified codeword is either the original message, or a completely unrelated value.

In the information theoretic setting, although existence of such codes for various ... more >>>

TR13-137 | 29th September 2013
Mohammad Mahmoody, Hemanta Maji, Manoj Prabhakaran

On the Power of Public-key Encryption in Secure Computation

We qualitatively separate semi-honest secure computation of non-trivial secure-function evaluation (SFE) functionalities from existence of key-agreement protocols.
Technically, we show the existence of an oracle (namely, PKE-oracle) relative to which key-agreement protocols exist; but it is useless for semi-honest secure realization of symmetric 2-party (deterministic finite) SFE functionalities, i.e. any ... more >>>

TR12-065 | 16th May 2012
Mohammad Mahmoody, Hemanta Maji, Manoj Prabhakaran

Limits of Random Oracles in Secure Computation

Revisions: 2

The seminal result of Impagliazzo and Rudich (STOC 1989) gave a black-box separation between one-way functions and public-key encryption: informally, a public-key encryption scheme cannot be constructed using one-way functions as the sole source of computational hardness. In addition, this implied a black-box separation between one-way functions and protocols for ... more >>>

TR09-123 | 23rd November 2009
Hemanta Maji, Manoj Prabhakaran, Mike Rosulek

Cryptographic Complexity Classes and Computational Intractability Assumptions

Which computational intractability assumptions are inherent to cryptography? We present a broad framework to pose and investigate this question.
We first aim to understand the “cryptographic complexity” of various tasks, independent of any computational assumptions. In our framework the cryptographic tasks are modeled as multi- party computation functionalities. We consider ... more >>>

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