We explore confidential communications for JANUS, the current underwater communications standard, with the goal of advancing current solutions. We focus on a solution published in May 2021 through two papers, titled Venilia and Tiny Underwater Block cipher (TUBcipher). The Venilia JANUS class was developed to provide functionality for symmetric cryptography in underwater communications, and the TUBcipher was designed for use with Venilia. Some important details were not provided or considered in these original papers, such as a security analysis of the TUBcipher and a key establishment/distribution solution. With the goal of improving Venilia, we provide these details. We conduct a security analysis for the TUBcipher with the objective of determining if it is semantically secure. We implemented the TUBcipher as described in the paper and collected the entropy of ciphertexts with the ENT tool. With results close the theoretical maximum value of entropy, we conclude that the TUBcipher is semantically secure. We also provide two key establishment/distribution solutions. These provide methods of practically implementing Venilia within underwater communication networks.