If i'm right, Quantum Computer is best for solving exponential problem (2^x) while Bitcoin cryptography either based on polynomial (x^2) or/and Elliptic-curve/ECDSA (y^2=x^3+ax+b), so bitcoin security won't affect much by Quantum Computer. CMIIW.
There are a couple errors, here. First, 2
x (
EXP) is way harder than x
2 (
P) - a computer that could solve 2
x problems wouldn't even have to break a sweat to solve x
2 problems.
In theory, quantum computers (QC) can store information exponentially in the number of qubits - 20 qubits can store a megabit (2
20 classical bits) of information. But the exponential space advantage of QC does not necessarily translate to an exponential time advantage. QC has a quadratic time advantage for
search problems vis-a-vis a classical computer.
Fools who think replacing science with math somehow makes for legitimate concepts...and after a google search followed by a link to wikipedia, we can rest assured you're all experts on quantum mysticism. haha