Abstract We study the hardness of the Syndrome Decoding problem, the base of most code-based cryptographic schemes, such as Classic McEliece, in the presence of side-channel information. We use ChipWhisperer equipment to perform a template attack on Classic McEliece running on an ARM Cortex-M4, and accurately classify the Hamming weights of consecutive 32-bit blocks of the secret error vector $$\textbf{e}\in {{\mathbb {F}}}_2^n$$ e ∈ F 2 n . With these weights at hand, we optimize Information Set Decoding algorithms. Technically, we demonstrate how to speed up information set decoding via a dimension reduction, additional parity-check equations, and an improved information set search, all derived from the Hamming-weight information. Consequently, using our template attack, we can practically recover an error vector $$\textbf{e}\in {{\mathbb {F}}}_2^n$$ e ∈ F 2 n in dimension $$n=2197$$ n = 2197 in a matter of seconds. Without side-channel information, such an instance has a complexity of around 88 bit. We also estimate how our template attack affects the security of the proposed McEliece parameter sets. Roughly speaking, even an error-prone leak of our Hamming weight information leads for $$n=3488$$ n = 3488 to a security drop of 89 bits.

Abstract In this survey, the authors review the main quantum algorithms for solving the computational problems that serve as hardness assumptions for cryptosystem. To this end, the authors consider both the currently most widely used classically secure cryptosystems, and the most promising candidates for post‐quantum secure cryptosystems. The authors provide details on the cost of the quantum algorithms presented in this survey. The authors furthermore discuss ongoing research directions that can impact quantum cryptanalysis in the future.

Blind signatures are a fundamental cryptographic primitive with numerous practical applications. While there exist many practical blind signatures from number-theoretic assumptions, the situation is far less satisfactory from post-quantum assumptions. In this work, we provide the first overall practical, lattice-based blind signature, supporting an unbounded number of signature queries and additionally enjoying optimal round complexity. We provide a detailed estimate of parameters achieved -- we obtain a signature of size slightly above 45KB, for a core-SVP hardness of 109 bits. The run-times of the signer, user and verifier are also very small.