CONTINUOUS NON-MALLEABLE CODES AND NON-MALLEABLE SECRET SHARING

Abstract

Non-malleable codes provide a useful message integrity guarantee in situations where traditional error-correction is impossible; for example, when the attacker can completely overwrite the encoded message. Continuous non-malleable codes allow for continuous tampering by the adversary.

We present the first efficient information-theoretically secure continuous non-malleable codes in the constant split-state model, where there is a self-destruct mechanism which ensures that the adversary loses access to tampering after the first failed decoding.

We also present a compiler that takes secret sharing schemes for an arbitrary access structures as input and produce non-malleable secret sharing schemes for the same access structure. Non-malleable secret sharing schemes guarantee that a secret that is reconstructed from a set of tampered shares is either equal to the original secret or completely unrelated.