We develop DroidCCT, a distributed test framework to evaluate the scale of a wide range of failures/bugs in cryptography for end users. DroidCCT relies on passive analysis of artifacts from the execution of cryptographic operations in the Android ecosystem to identify weak implementations. We collect trillions of samples from cryptographic operations of Android Keystore on half a billion devices and apply severalanalysis techniques to evaluate the quality of cryptographic output from these devices and their underlying implementations. Our study reveals several patterns of bugs and weakness in cryptographic implementations from various manufacturers and chipsets. We show that the heterogeneous nature of cryptographic implementations results in non-uniform availability and reliability of various cryptographic functions. More importantly, flaws such as the use of weakly-generated random parameters, and timing side channels may surface across deployments of cryptography. Our results highlight the importance of fault- and side-channel-resistant cryptography and the ability to transparently and openly test these implementations.
@article{arxiv.2601.11745,
title = {DROIDCCT: Cryptographic Compliance Test via Trillion-Scale Measurement},
author = {Daniel Moghimi and Alexandru-Cosmin Mihai and Borbala Benko and Catherine Vlasov and Elie Bursztein and Kurt Thomas and Laszlo Siroki and Pedro Barbosa and Remi Audebert},
journal= {arXiv preprint arXiv:2601.11745},
year = {2026}
}