Post-Quantum Cryptography
Post-Quantum Cryptography
Markus Grassl,Brandon Langenberg,Martin Rötteler,R. Steinwandt
TLDR
This work presents quantum circuits to implement an exhaustive key search for the Advanced Encryption Standard AES and establishes precise bounds for the number of qubits and the number of elementary logical quantum gates that are needed to implement Grover's quantum algorithm to extract the key from a small number of AES plaintext-ciphertext pairs.
Abstract
We present quantum circuits to implement an exhaustive key search for the Advanced Encryption Standard AES and analyze the quantum resources required to carry out such an attack. We consider the overall circuit size, the number of qubits, and the circuit depth as measures for the cost of the presented quantum algorithms. Throughout, we focus on Clifford
+Tgates as the underlying fault-tolerant logical quantum gate set. In particular, for all three variants of AES key size 128, 192, and 256i¾źbit that are standardized in FIPS-PUB 197, we establish precise bounds for the number of qubits and the number of elementary logical quantum gates that are needed to implement Grover's quantum algorithm to extract the key from a small number of AES plaintext-ciphertext pairs.