Quantum Computing will NOT even touch cryptocurrency
If you spend some time training on the 5 Qubit IBM training system you will learn in the literature that it can only reduce the problem set by a SQRT.
This is a reference to hashing algorithms and Grover's solution.
Shor's solution breaks public key cryptography:
https://en.wikipedia.org/wiki/Shor's_algorithm"If a quantum computer with a sufficient number of qubits could operate without succumbing to noise and other quantum decoherence phenomena, Shor's algorithm could be used to break public-key cryptography schemes such as the widely used RSA scheme."
All cryptos using ECDSA are highly vulnerable.