As the validation and trials of fifth generation communication architectures are maturing, it becomes evident that efficient bandwidth utilization, security, and seamless cooperation among heterogeneous small cell access networks are among the vital requirements that the future wireless networks must satisfy. A potential candidate technology that can ensure bandwidth efficiency and high resilient communications, especially in the adverse wireless networking conditions is network coding. However, without a security strategy for protecting the data and the identity of the communication entities, network coding can be proved as a factor of severely degrading networking performance. Although several cryptography based schemes have been used over the recent years to ensure secure communications over network coding enabled networks, none was specifically designed to address the mobile small cell access network of the forthcoming fifth- generation paradigm. This paper proposes a secure network coding architecture for mobile small cells, which due to their unpredictable topology, render the most encryption key management schemes unsuitable and costly in terms of signaling. The proposed secure network coding architecture incorporates blockchains in an effort to ensure efficient key distribution and reduced signaling overhead.