An Ultra-lightweight White-box Encryption Scheme for Securing Resource-constrained IoT Devices

Embedded devices with constrained computational resources, such as wireless sensor network nodes, electronic tag readers, roadside units in vehicular networks, and smart watches and wristbands, are widely used in the Internet of Things. Many of such devices are deployed in untrustable environments, and others may be easy to lose, leading to possible capture by adversaries. Accordingly, in the context of security research, these devices are running in the white-box attack context, where the adversary may have total visibility of the implementation of the built-in cryptosystem with full control over its execution. It is undoubtedly a significant challenge to deal with attacks from a powerful adversary in white-box attack contexts. Existing encryption algorithms for white-box attack contexts typically require large memory use, varying from one to dozens of megabytes, and thus are not suitable for resource-constrained devices. As a countermeasure in such circumstances, we propose an ultra-lightweight encryption scheme for protecting the confidentiality of data in white-box attack contexts. The encryption is executed with secret components specialized for resource-constrained devices against white-box attacks, and the encryption algorithm requires a relatively small amount of static data, ranging from 48 to 92 KB. The security and efficiency of the proposed scheme have been theoretically analyzed with positive results, and experimental evaluations have indicated that the scheme satisfies the resource constraints in terms of limited memory use and low computational cost.