Classifying Computations on Multi-Tenant FPGAs.

Modern data centers leverage large FPGAs to provide low latency, high throughput, and low energy computation. FPGA multi-tenancy is an attractive option to maximize utilization, yet it opens the door to unique security threats. In this work, we develop a remote classification pipeline that targets the confidentiality of multi-tenant cloud FPGA environments. We design a unique Dual-Edged voltage fluctuation sensor that measures subtle changes in the power distribution network caused by co-located computations. The sensor measurements are given to a classification pipeline that is able to deduce information about co-located applications including the type of computation and its implementation. We study the importance of the trace length, signal conditioning algorithms, and other aspects that affect classification accuracy. Our results show that we can determine if another co-tenant is present with 96% accuracy. We can classify with 98% accuracy whether a power waster circuit is operating. Furthermore, we are able to determine if a cryptographic operation is occurring, differentiate between different cryptographic algorithms (AES and PRESENT) and microarchitectural implementations (Microblaze, ORCA, and PicoRV32).