Uni-directional trusted path: Transaction confirmation on just one device

Commodity computer systems today do not include a full trusted path capability. Consequently, malware can control the user's input and output in order to reveal sensitive information to malicious parties or to generate manipulated transaction requests to service providers. Recent hardware offers compelling features for remote attestation and isolated code execution, however, these mechanisms are not widely used in deployed systems to date. We show how to leverage these mechanisms to establish a “one-way” trusted path allowing service providers to gain assurance that users' transactions were indeed submitted by a human operating the computer, instead of by malware such as transaction generators. We design, implement, and evaluate our solution, and argue that it is practical and offers immediate value in e-commerce, as a replacement for captchas, and in other Internet scenarios.