The notion of non-malleable cryptography, an extension of semantically secure cryptography , is deened. Informally, the additional requirement is that given the ciphertext it is impossible to generate a diierent ciphertext so that the respective plaintexts are related. The same concept makes sense in the contexts of string commitment and zero-knowledge proofs of possession of knowledge. Non-mal...

The recent line of study on randomness extractors has been a great success, resulting in exciting new techniques, new connections, and breakthroughs to long standing open problems in the following five seemingly different topics: seeded non-malleable extractors, privacy amplification protocols with an active adversary, independent source extractors (and explicit Ramsey graphs), non-malleable in...

We construct non-malleable codes in the split-state model with codeword length m + 3λ or 5λ, where is message size and λ security parameter, depending on how conservative one is. Our scheme very simple involves a single call to block cipher meeting new notion which we dub entropic fixed-related-key security, essentially means that behaves like pseudorandom permutation when queried upon inputs s...

Non-malleability is an interesting and useful property which ensures that a cryptographic protocol preserves the independence of the underlying values: given for example an encryption E(m) of some unknown message m, it should be hard to transform this ciphertext into some encryption E(m∗) of a related message m∗. This notion has been studied extensively for primitives like encryption, commitmen...

Non-malleable codes are randomized codes that protect coded messages against modification by functions in a tampering function class. These codes are motivated by providing tamper resilience in applications where a cryptographic secret is stored in a tamperable storage device and the protection goal is to ensure that the adversary cannot benefit from their tamperings with the device. In this pa...

We study relations among various notions of complete nonmalleability, where an adversary can tamper with both ciphertexts and public-keys, and ciphertext indistinguishability. We follow the pattern of relations previously established for standard non-malleability. To this end, we propose a more convenient and conceptually simpler indistinguishability-based security model to analyse completely n...

There are several candidate semantically secure encryption schemes, yet in many applications non-malleability of encryptions is crucial. We show how to transform any semantically secure encryption scheme into one that is non-malleable for arbitrarily many messages.

Non-Interactive Zero Knowledge (NIZK), introduced by Blum, Feldman, and Micali in 1988, is a fundamental cryptographic primitive which has attracted considerable attention in the last decade and has been used throughout modern cryptography in several essential ways. For example, NIZK plays a central role in building provably secure public-key cryptosystems based on general complexity-theoretic ...