Protecting cryptographic keys and computations via virtual secure coprocessing

Abstract

Cryptographic processing is a critical component of secure networked computing systems. The protection offered by cryptographic processing, however, greatly depends on the methods employed to manage, store, and exercise a user's cryptographic keys. In general, software-only key management schemes contain numerous security weaknesses. Thus, many systems protect keys with distributed protocols or supplementary hardware devices, such as smart cards and cryptographic coprocessors. However, these key protection mechanisms suffer from combinations of user inconvenience, inflexibility, performance penalties, and high cost.In this paper, we propose architectural enhancements for general-purpose processors that protect core secrets by facilitating virtual secure coprocessing (VSCoP). We describe modest hardware modifications and a trusted software library that allow common computing devices to perform flexible, high-performance, and protected cryptographic computation. The hardware additions include a small key store in the processor, encryption engines at the cache-memory interface, a few new instructions, and minor hardware platform modifications. With these enhancements, users can store, transport, and employ their secret keys to safely complete cryptographic operations in the presence of insecure software. In addition, we provide a foundation with which users can more securely access their secret keys on any Internet-connected computing device (that supports VSCoP) without requiring auxiliary hardware such as smart cards.