A personal cloud authentication (PCA) system for authenticating an online user using device data stored on a personal cloud platform of the user is provided. The PCA system configured to build an authentication table using a user profile that includes at least user account information. The PCA system is also configured to receive transaction data associated with the user account information and store the transaction data within a database, wherein the transaction data includes at least an authentication request, a second primary user computing device identifier and a second secondary user computing device identifier. The PCA system is further configured to parse the transaction data, match the first primary user computing device identifier to the second primary user computing device identifier and the first secondary user computing device identifier to the second secondary user computing device identifier, generate an authentication response based on the match, and transmit the authentication response.