Hidden subgroup ยท Algorithms
Polynomial-time elliptic-curve discrete logarithm
Theorem statement
Let $p>3$ be prime, $E/\mathbb F_p$ be a short Weierstrass
elliptic curve, $P\in E(\mathbb F_p)$ be a known point
of known prime order $r$, $Q\in\langle P\rangle$ be a known
point other than the point at infinity, and $0<\eta\leq1$.
Set $f=\lceil\log_2p\rceil$, $t=\lceil\log_2(12r)\rceil$,
and $k=\lceil\log\eta/
\log(1-r(r-1)/2^{2t+2})\rceil$.
Given access to an oracle $U_{P,Q}$ satisfying
$U_{P,Q}\ket{a,b,R}=\ket{a,b,R+[a]P-[b]Q}$,
there exists a quantum algorithm that returns
$m\in\{0,\ldots,r-1\}$ satisfying $Q=[m]P$
with probability at least $1-\eta$, using at most
$2t+2f+1$ logical qubits,
$k$ queries to $U_{P,Q}$,
$k(2t^2+4t+6\lfloor t/2\rfloor)$ CNOT gates,
$k(3t^2+25t+4f+3)$ single-qubit gates,
$2t+2f+2+k\left(5t^2+248ft+721t+8f+6\lfloor t/2\rfloor+125\right)$
quantum computation time,
$\max\{18t^2+70t+70,18f^2+72f+69\}+6f+4t+8$
classical bits,
and $k(248ft+686t+119)+1$ classical operations.
Sources
- Shor's discrete logarithm quantum algorithm for elliptic curves
John Proos, Christof Zalka, 2003
- An efficient quantum algorithm for preparation of uniform quantum superposition states
Alok Shukla, Prakash Vedula, 2024
Lean context
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