Revision history [back]
 | 1 | initial version |
While the option is not exposed to Sage, you can call it through the Pari interface:
E = EllipticCurve(GF(2^255-19), [0, 486662, 0, 1, 0])
e = gp.ellinit(E.a_invariants(), E.base().order())
order = e.ellsea(tors=2)
print(order)
| | 2 | No.2 Revision |
While the option is not exposed to Sage, you can call it through the Pari interface:
E = EllipticCurve(GF(2^255-19), [0, 486662, 0, 1, 0])
e = gp.ellinit(E.a_invariants(), E.base().order())
order = e.ellsea(tors=2)
print(order)
The documentation for the tors parameter:
When tors is set to a non-zero value, the function returns 0 as soon as it detects that the order has a small prime factor not dividing tors; SEA considers modular polynomials of increasing prime degree ℓ and we return 0 as soon as we hit an ℓ (coprime to tors) dividing #E(𝔽_q).
The development version of Pari also supports checking the order of the twist (by using a negative tors), but it has not been released yet (and not integrated with Sage) as I write this.
