Security and privacy concerns in the future power grid have recently received tremendous focus from security advocates. Most existing security mechanisms utilize cryptographic techniques that are computationally expensive and bandwidth intensive. However, aggregating the large outputs of these cryptographic algorithms has not been considered thoroughly. Smart Grid Networks (SGN) generally have limitations on bandwidth, network capacity and energy. Hence, utilizing data aggregation algorithms, the limited bandwidth can be efficiently utilized. Most of the aggregation algorithms use statistical functions such as minimum, maximum, and average. before transmitting data over the network. Existing aggregation algorithms, in SGNs, are generally expensive in terms of communication overhead, processing load and delay. However, our proposed CDMA-based data aggregation method provides access to all the data of all the smart meters in the root node, which in this case is the Utility Center, while keeping the smart metering data secure. The efficiency of the proposed method is confirmed by mathematical analysis.