Most postulations I've seen follow the axiom that the number of qubits must be no less than twice the number of bits used to generate the key. I found a pretty

Most postulations I've seen follow the axiom that the number of qubits must be no less than twice the number of bits used to generate the key. I found a pretty good summary of that thinking on StackExchange: https://security.stackexchange.com/questions/87345/how-many-qubits-are-needed-to-factor-2048-bit-rsa-keys-on-a-quantum-computer https://security.stackexchange.com/questions/87345/how-many-...