Abstract: A network builder (NB) computing device for building a peer network used to authenticate suspect payment transactions and thereby improve data security over a payment network is provided. The NB computing device includes a processor in communication with a memory. The processor retrieves candidate historical transaction data for a candidate cardholder including a first plurality of historical data elements and retrieves model historical transaction data for a plurality of model cardholders including a second plurality of historical data elements. The model historical transaction data includes previously authenticated and authorized payment transactions. The processor compares the candidate historical transaction data to the model historical transaction data, identifies matching historical data elements, and builds a first peer network between the candidate cardholder and a first set of model cardholders associated with the matching historical data elements. The first peer network is stored in the memory.