Cryptographic Security And Key Management In Multi-Platform IOT Systems: Implementation And Performance Aspects

Smart-city services rely on many small sensors that send data about traffic, energy,and air quality. Each message must stay private and unaltered, yet the devices thatsend them have little memory, slow CPUs, and limited power. This thesis builds andtests a light but strong key-management system that fits these limits. The protocoluses elliptic curve certificates and elliptic curve Diffie–Hellman key exchange to setup a shared secret. Then, for every message between client and server, a symmetrickey is derived from the shared secret. The shared secret, and elliptic curve keys onthe server are renewed periodically to decrease the damage in case of compromise.The proposed protocol is formally verified using Tamarin Prover. Long-term keyson the server sit inside a TPM 2.0 chip, which adds an extra layer of security forstorage of the keys. The protocol is deployed in a web-API, and performance testson the protocol and individual cryptographic operations used by the protocol arecarried out on a set of single-board computers representing generic IoT devices. Theresults show that by the proposed protocol, the key exchange operations completein reasonable amounts of time where majority of the time is spent by the