Content Centric Networking (CCN) is a promising routing paradigm for content dissemination over the Internet of the future based on named data instead of named hosts. The CCN architecture will enable more scalable, secure, collaborative and pervasive networking. In particular, the CCN security scheme relies on the authentication of every transmitted content; which must be signed. However, this introduces new challenges regarding the authentication of content through the management of encryption keys linked to content providers. To keep the privacy and integrity of content using encryption, a proper key management scheme is necessary to authenticate the encryption key as well. In this paper, we propose an online public key generation technique which is suited for the CCN architecture. We analyze the proposed technique using the ccnSim simulator to evaluate its performance and the AVISPA tool to assess its security. Besides specific features, our scheme shows better performance in terms of time taken by a node to retrieve and generate a public key for the received content compared to the standard PKI approach.