  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 paper we consider non-malleable codes for protection of secure
communication against active physical layer adversaries. We define a class of
functions that closely model tampering of communication by adversaries who can
eavesdrop on a constant fraction of the transmitted codeword, and use this
information to select a vector of tampering functions that will be applied to a
second constant fraction of codeword components (possibly overlapping with the
first set). We derive rate bounds for non-malleable codes for this function
class and give two modular constructions. The first construction adapts and
provides new analysis for an existing construction in the new setting. The
second construction uses a new approach that results in an explicit
construction of non-malleable codes. We show applications of our results in
securing message communication against active physical layer adversaries in two
settings: wiretap II with active adversaries and Secure Message Transmission
(SMT) in networks. We discuss our results and directions for future work.
