This disclosure provides various embodiments of systems and methods for secure communications. In one aspect, the system includes a secure payment module (SPM) in a fuel dispenser and a point-of-sale (POS) system. The POS system stores a public key certificate uniquely identifying the SPM and is configured to dynamically generate a first session key. The POS system encrypts the first session key with a public key associated with the public key certificate, and transmits the encrypted first session key to the SPM. The SPM, which stores a private key associated with the public key certificate, is configured to receive and decrypt the first session key. The SPM is further configured to receive a set of magnetic card data from a card reader, encrypt the set of magnetic card data with the first session key, and transmit the encrypted set of magnetic card data to the POS system.