Non-malleable Coding for Arbitrary Varying Channels
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Non-malleable codes were proposed in tamper resilient cryptology with the goal of preventing an adversary from tampering with the protected message in a message-specific way. Adversarial noise in coding theory is usually modelled as an Arbitrary Varying Channel (AVC), where reliable transmission has been the prime concern of study and hence restricted the study to very limited AVC. We introduce non-malleability as a coding goal into the study of AVC and show that non-malleability is achievable at rate asymptotically 1 with respect to any AVC. As an application to secure communication, we then consider a setting of an AVC with a special state s* and an additional requirement: when s* is applied to all the codeword bits, the message can be recovered by the receiver; when an arbitrary state sequence however, non-malleability is achieved. We outline a message encoding that achieves these goals.
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