Design of a secure software download algorithm in software defined radio terminals using quantum cryptography

A software defined radio (SDR) terminal may be regarded as a programmable radio transceiver whereby the user equipment is able to reconfigure itself, in terms of its capability, functionality and behavior, in order to accommodate the needs of the user dynamically. The terminal must be able to switch from one mode to another if the quality of the incumbent mode becomes unacceptable or a new mode is preferred. The mode switch may involve downloading appropriate software. When the SDR terminal decides to switch to a different mode, it triggers a software download process. The reconfiguration agent submits the software of the new mode and its hardware to the authorities for testing. Once the combination of software and hardware has been approved, the hash is assigned using the approval authority´s secret key. The software along with the digital signature is encrypted using the secret key of the terminal which requested the software download. The encrypted data is sent to the terminal, which decrypts it using the secret key and gets the software for the appropriate mode and verifies the digital signature of the authority. The paper describes a novel technique, using quantum cryptography, for secret key distribution between the reconfiguration agent and the terminal.