A non-malleable extractor is a seeded extractor with a very strong guarantee – the output of a non-malleable extractor obtained using a typical seed is close to uniform even conditioned on the output obtained using any other seed. The first contribution of this paper consists of two new and improved constructions of non-malleable extractors: We construct a non-malleable extractor with seed-leng...

A non-malleable code protects messages against various classes of tampering. Informally, a code is non-malleable if the message contained in a tampered codeword is either the original message, or a completely unrelated one. Although existence of such codes for various rich classes of tampering functions is known, explicit constructions exist only for “compartmentalized” tampering functions: i.e...

Algebraic manipulation detection codes are a class of error detecting codes which have found numerous applications in cryptography. In this paper we extend these codes to defeat general algebraic attacks we call such codes general algebraic manipulation detection (GAMD) codes. Positive results are shown for the existence of GAMDs for the families of tampering functions corresponding to point ad...

Non-malleable codes were introduced by Dziembowski et al. (ICS 2010) as coding schemes that protect a message against tampering attacks. Roughly speaking, a code is non-malleable if decoding an adversarially tampered encoding of a message m produces the original message m or a value m ′ (possibly ⊥) completely unrelated to m . It is known that non-malleability is possible only for restricted cl...

We introduce the notion of “non-malleable codes” which relaxes the notion of error-correction and errordetection. 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 contrast to error-correction and error-detection, nonmalleability can be achieved for very rich classes of modifications. We constr...

An encryption scheme is non-malleable if the adversary cannot transform a ciphertext into one of a related message under the given public key. Although providing a very strong security property, some application scenarios like the recently proposed key-substitution attacks yet show the limitations of this notion. In such settings the adversary may have the power to transform the ciphertext and ...

Non-malleable codes are a natural relaxation of error correcting/detecting codes that have useful applications in the context of tamper resilient cryptography. Informally, a code is non-malleable if an adversary trying to tamper with an encoding of a given message can only leave it unchanged or modify it to the encoding of a completely unrelated value. This paper introduces an extension of the ...

In this report,based on the paper of Dziembowski et al.'s [DPW10], we explain how we can construct an e cient code that is nonmalleable with respect to modi cations that e ect each bit of the codeword arbitrarily. A variety of modi cations of codewords are considered such as ipping each bit of the codeword, leaving it untouched, or setting it to either 0 or 1 but independently of the value of t...

We construct the first constant-round non-malleable commitment scheme and the first constantround non-malleable zero-knowledge argument system, as defined by Dolev, Dwork and Naor. Previous constructions either used a non-constant number of rounds, or were only secure under stronger setup assumptions. An example of such an assumption is the shared random string model where we assume all parties...