A secure data exchange system permits device to exchange secure message keys and securely transmit messages between devices. The devices may initially exchange temporary message keys that are used to encrypt permanent message keys. In addition, devices may have pairing managed that authenticates devices. Devices may be associated with an address ledger that maintains address information and is accessible with a public ledger key, which may provide different access to address information to different paired devices. Data within the system may also be encrypted with user device keys that prevents unauthorized access to data while permitting recreation of the user device key for data backup and migration.