Short message noisy network coding (SNNC) differs from long message noisy network coding (LNNC) in that one transmits many short messages in blocks rather than using one long message with repetitive encoding. Two properties of SNNC are developed. First, SNNC with backward decoding achieves the same rates as SNNC with offset encoding and sliding window decoding for memoryless networks where each node transmits a multicast message. The rates are the same as LNNC with joint decoding. Second, SNNC enables early decoding if the channel quality happens to be good. This leads to mixed strategies that unify the advantages of decode-forward and noisy network coding.

A security measure called effective security is defined that includes strong secrecy and stealth communication. Effective secrecy ensures that a message cannot be deciphered and that the presence of meaningful communication is hidden. To measure stealth we use resolvability and relate this to binary hypothesis testing. Results are developed for wire-tap channels and broadcast channels with confidential messages.

Short message noisy network coding (SNNC) transmits independent short messages in blocks rather than using long message repetitive encoding. SNNC is shown to achieve the same rates as noisy network coding (NNC) for discrete memoryless networks where each node transmits a multicast message. One advantage of SNNC is that backward decoding may be used which simplifies the analysis and understanding of the achievability proof. The analysis reveals that each decoder may ignore certain other nodes rather than including their message in the decoding procedure. Additionally, SNNC enables early decoding at nodes if the channel quality happens to be good.

Quantize-map-forward (QMF) and noisy network coding (NNC) differ primarily from compress-forward relaying in that relays do not hash their quantization bits. Two further differences are that source nodes use “long”-message repetitive encoding and destination nodes use simultaneous joint decoding. Recent work has shown that classic “short”-message encoding combined with backward decoding achieves the same rates as QMF and NNC. A simplified proof of this result is given.