| Speaker Affiliation | Post-Doc, KU Leuven, Belgien |
| Start | 22.01.2016, 15:00 Uhr |
| Location | TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23, 1. OG, Hörsaal M 161 |
| Invited by | Prof. Dr. Rüdiger Kapitza |
| Protected-module architectures such as Intel SGX provide strong isolation guarantees to sensitive parts of applications while the system is up and running. Unfortunately, systems in practice crash, go down for reboots or lose power at unexpected moments in time. To deal with such events, additional security measures need to be taken to guarantee that stateful modules will either recover their state from the last stored state, or fail-stop on detection of tampering with that state. More specifically, protected-module architectures need to provide a security primitive that guarantees that (1) attackers cannot present a stale state as being fresh (i.e.~rollback protection) and (2) an unexpected loss of power must never leave the system in a state from which it can never advance (i.e.~liveness guarantee). Existing, practically feasible solutions take advantage of an uninterruptible power source (UPS), but such guarantees may be hard to implement and increase the economic cost of the overall platform. We propose Ariadne, a solution to the state-continuity problem that achieves the theoretical lower limit of requiring only a single bit flip of non-volatile memory per state update. This is important in practice as secure, non-volatile memory is usually slow, limited in size, and wears out quickly. Ariadne can be configured to make optimal use of such memory. TPM NVRAM fulfils all security requirements we demand of secure, non-volatile memory. As TPM chips are already widely deployed on commodity hardware, including the recently launched, SGX-enabled Skylake processors from Intel, Ariadne can be readily deployed to protect stateful SGX enclaves (e.g., as used by Haven and VC3). We show that with reasonable assumptions of TPM NVRAM, we can guarantee up to 2^29 state updates. | |