International Association
for Cryptologic Research

The recent Hertzbleed disclosure demonstrates how remote-timing analysis can reveal secret information previously only accessible to local-power analysis. At worst, this constitutes a fundamental break in the constant-time programming principles and the many deployed programs that rely on them. But all hope is not lost. Hertzbleed relies on a coarse-grained, noisy channel that is difficult to exploit. Indeed, the Hertzbleed paper required a bespoke cryptanalysis to attack a specific cryptosystem (SIKE). Thus, it remains unclear if Hertzbleed represents a threat to the broader security ecosystem. In this paper, we demonstrate that Hertzbleed's effects affect cryptosystems beyond SIKE. We demonstrate how latent gadgets in other cryptosystem implementations---specifically ``constant-time'' ECDSA and Classic McEliece---can be combined with existing cryptanalysis to bootstrap Hertzbleed attacks on those cryptosystems.