Random linear network coding has been demonstrated to be able to improve the performance of many peer-to-peer applications, such as content distribution, multimedia streaming, distributed storage, and wireless communications. We first survey recent research progress in applying RLNC in P2P content distribution and multimedia streaming, respectively. We then study the pollution attack, a primary type of security threat particularly relevant to RLNC, and present and compare some existing countermeasures. We finally discuss confidentiality and privacy issues in RLNCenabled P2P applications as future research challenges.