Notary: A DEVICE FOR SECURE TRANSACTION APPROVAL

摘要

Notary is a case study in designing for security. Notary simplifies software (e.g., using reset-based agent switching) and simplifies hardware (e.g., using physical separation) in order to achieve strong isolation and defense in depth. This separation and reset-based switching eliminates by design classes of bugs that affect traditional user/kernel co-resident designs, including OS bugs, microarchitectural side-channels, and certain hardware bugs. Notary can improve the security of applications where the crucial transaction decision can be succinctly summarized and delegated to a strongly isolated agent running on Notary. Users have embraced hardware wallets for use with cryptocurrencies, a high-stakes operation where the overhead of using a hardware wallet is justified. In the future, we hope to see more secure and seamless support for transaction approval on smartphones, which already have much of the hardware needed to provide such functionality.