New publication: “GPU-Enhanced Brute Force Cryptanalysis of GPRS, GSM, RFID, and TETRA: Brute Force Analysis of KASUMI, SPECK, and TEA3.”

Summary: The key sizes in symmetric encryption are established in relation to potential brute force assaults with existing technology. Currently, at least 128-bit keys are advised, yet numerous standards and practical applications continue to utilize shorter keys. To accurately gauge the genuine risk associated with these shorter keys, precise evaluations of potential attacks are essential.

In this study, we present enhanced implementations of various commonly utilized algorithms on GPUs, yielding significant insights into the expense of brute force attacks on multiple real-world applications.

Specifically, we enhance KASUMI (employed in GPRS/GSM), SPECK (utilized in RFID communication), and TEA3 (applied in TETRA). Our optimal enhancements enable us to attempt 235.72, 236.72, and 234.71 keys each second on a solitary RTX 4090 GPU. These findings represent a substantial advancement over previous results, such as our KASUMI implementation being over 15 times quicker than the optimizations presented in the CRYPTO’24 paper [ACC+24], improving the principal outcomes of that paper by the same margin.

With these advancements, to compromise GPRS/GSM, RFID, and TETRA communications within a single year, one would require approximately 11.22 billion and 1.36 million RTX 4090 GPUs, respectively.

For KASUMI, the time-memory trade-off strategies from [ACC+24] might be executed with 142 RTX 4090 GPUs rather than 2400 RTX 3090 GPUs or, if the same quantity of GPUs is utilized, their table generation time can be decreased to 20.6 days from 348 days, which are critical enhancements for real-world cryptanalytic endeavors.

Attacks consistently improve; they never decrease in effectiveness. While none of these methods are currently practical, they may never be. However, it is certain that further optimizations are on the horizon.