Erasure adversarial wiretap channels

In an erasure adversarial wiretap channel (eAWTP-channel), the adversary can select a fraction ρr of the codeword to read, and a fraction ρe of the codeword to erase. The model can be seen as an extension of the wiretap II model where the adversary not only selects its view of the transmitted word, but also can erase a fraction of the codeword. eAWTP codes provide security and reliability for communication over eAWTP channels. We derive an upper bound on the rate of eAWTP codes, and give an efficient construction of a code family that achieves the bound, hence deriving secrecy capacity of the channel. We then show that the construction can also be used for AWTP channels in which instead of erasing code components, the adversary can add noise to the codeword. The construction is the only AWTP code with constant alphabet size.