  Contemporary IoT environments, such as smart buildings, require end-users to
trust data-capturing rules published by the systems. There are several reasons
why such a trust is misplaced --- IoT systems may violate the rules
deliberately or IoT devices may transfer user data to a malicious third-party
due to cyberattacks, leading to the loss of individuals' privacy or service
integrity. To address such concerns, we propose IoT Notary, a framework to
ensure trust in IoT systems and applications. IoT Notary provides secure log
sealing on live sensor data to produce a verifiable `proof-of-integrity,' based
on which a verifier can attest that captured sensor data adheres to the
published data-capturing rules. IoT Notary is an integral part of TIPPERS, a
smart space system that has been deployed at UCI to provide various real-time
location-based services in the campus. IoT Notary imposes nominal overheads for
verification, thereby users can verify their data of one day in less than two
seconds.
