Systems, devices, and methods for secure data management and transfer for secure data transactions are provided. For example, disclosed herein are secure & tamper resistant smart cards configured to immutably store data and securely exchange at least a portion of the data via, for example, wireless networks and/or peer-to-peer networks. The smart cards comprise a plurality of dedicated hardware circuit blocks electrically coupled via a bus interconnection, the plurality of dedicated hardware circuit blocks configured to authenticate users, verify trust amongst the smart card and external devices, and encrypt sensitive data for secure transmission.