Security of Elliptic Curve Digital Signature Algorithm (ECDSA) depends on the secrecy of the per-signature nonce. Even partial nonce leakage can expose the long-term private key through lattice-based cryptanalysis. In this paper, we introduce a previously unexplored power side-channel vulnerability that exploits sleep-induced power spikes to extract ECDSA nonces. Unlike conventional power-based side-channel attacks, this vulnerability leverages power fluctuations generated during processor context switches invoked by sleep functions. These fluctuations correlate with nonce-dependent operations in scalar multiplication, enabling nonce recovery even under constant-time and masked implementations. We evaluate the attack across multiple cryptographic libraries, RustCrypto, BearSSL, and GoCrypto, and processor architectures, including ARM and RISC-V. Our experiments show that subtle variations in the power envelope during sleep-induced context switches provide sufficient leakage for practical ECDSA nonce extraction, recovering 20 bits of the nonce. These results establish sleep-induced power spikes as a practical cross-platform side-channel threat and highlight the need to reconsider design choices in cryptographic systems.

翻译：椭圆曲线数字签名算法（ECDSA）的安全性依赖于每签名随机数的保密性。即使随机数部分泄漏，也可通过基于格点的密码分析暴露长期私钥。本文提出一种先前未被探索的功耗侧信道漏洞，该漏洞利用休眠诱导的功耗尖峰来提取ECDSA随机数。与传统的基于功耗的侧信道攻击不同，此漏洞利用由休眠函数触发的处理器上下文切换期间产生的功耗波动。这些波动与标量乘法中依赖随机数的操作相关，即使在恒定时间和掩码实现下也能实现随机数恢复。我们在多个密码库（RustCrypto、BearSSL、GoCrypto）和处理器架构（包括ARM和RISC-V）上评估了该攻击。实验表明，休眠诱导上下文切换期间功耗包络的细微变化为实际ECDSA随机数提取提供了足够泄漏，可恢复随机数的20位。这些结果确立了休眠诱导功耗尖峰作为一种实用的跨平台侧信道威胁，并强调需要重新考虑密码系统中的设计选择。