Development of Tamper-resistant Post-Quantum Cryptographic Hardware

在本财政年度，我们对SABER后量子加密（PQC）密钥交换算法在以下两个领域进行了研究。硬件实现我们在多个模型中实现了散列函数SHA-256和SHAKE-128，包括资源有效的全流水线实现，以及部分展开的低延迟实现。我们设计了计算模块同时执行的调度，使得密钥交换的硬件实现可以并行化算法的多个步骤。我们考虑了(A)利用被攻击设备发出的电磁辐射对PQC算法乘法模块的传统侧信道攻击；(B)我们提出了一种新的侧信道攻击，它可以利用展开分组密码和哈希函数中的路径激活偏差，例如在SABER中使用的SHA-256； (C)对PQC的故障注入攻击，故意在被攻击设备处理PQC密钥交换时产生错误的计算。我们认为(A)的研究在其他作品中已经被广泛考察过，所以我们没有进行详细的研究。然而，使用(B)，我们展示了一种新型的侧通道泄漏，可以利用它来揭示哈希算法的秘密输入。此外，使用(C)，我们发现攻击者可以通过在设备中使用的时钟信号中注入错误来跳过一些计算，从而泄露有关密钥交换的秘密信息。

During this fiscal year, we carried out research into the SABER post-quantum cryptographic (PQC) key exchange algorithm in the the following 2 areas.1. Hardware implementationWe implemented hashing functions SHA-256 and SHAKE-128 in multiple models, including the resource effective fully pipelined implementation, and the partially unrolled, low latency implementation. We designed the scheduling of simultaneous execution of computation modules which allows the hardware implementation of the key exchange to parallelize several steps of the algorithm.2. Side-channel security evaluationWe considered (A) traditional side-channel attacks on multiplication modules of PQC algorithms using electro-magnetic radiation emanating from the attacked device (B) a new side-channel attack we proposed which can exploit path activation biases in unrolled block ciphers and hashing functions, such as SHA-256 used in SABER (C) fault injection attacks on PQC, which intentionally produce erroneous computation in the attacked device processing the PQC key exchange. We believe the research of (A) is widely examined in other works, so we did not pursue it in detail. However, using (B), we demonstrated a new type of side-channel leakage that might be exploited to reveal secret inputs of the hashing algorithms. Further, using (C), we found that an attacker may reveal secret information about the key exchange by injecting faults into the clock signal used in the device to skip some computation.