Accelerated remotely keyed encryption

Abstract

Remotely keyed encryption schemes (RKESs) support fast encryption and decryption using low-bandwidth devices, such as secure smartcards. The long-lived secret keys never leave the smartcard, but most of the encryption is done on a fast untrusted device, such as the smartcard’s host. This paper describes an new scheme, the length-preserving “accelerated remotely keyed" (ARK) encryption scheme and, in a formal model, provides a proof of security. For the sake of practical usability, our model avoids asymptotics. Blaze, Feigenbaum, and Naor gave a general definition for secure RKESs [3]. Compared to their length-preserving scheme, the ARK scheme is more efficient but satisfies the same security requirements.