ringabout
commented
2 months ago !nim c
type BigInt[N: static int] = object
raw: array[N, uint64]
func isZero(a: BigInt): bool =
discard
func isOne(a: BigInt): bool =
discard
type
QuadraticExt*[F] = object
## Quadratic Extension field
coords*: array[2, F]
CubicExt*[F] = object
## Cubic Extension field
coords*: array[3, F]
ExtensionField*[F] = QuadraticExt[F] or CubicExt[F]
func isOne*(a: ExtensionField): bool =
## Constant-time check if one
result = 1'u64
result = result and a.coords[0].isOne()
for i in 1 ..< a.coords.len:
result = result and a.coords[i].isZero()
func mulCheckSparse*(a: var QuadraticExt, b: static QuadraticExt) {.inline.} =
static:
debugEcho "QuadraticExt b: ", b is QuadraticExt # This is true
debugEcho "ExtensionField b: ", b is ExtensionField # This is false
when isOne(b).bool:
discard
else:
debugEcho "a *= b"
type EllipticCurve*[F] = object
x*, y*, z*: F
template sumImpl[F](
r: var EllipticCurve[F],
P, Q: EllipticCurve[F],
CoefA: typed) {.dirty.} =
when CoefA is int:
debugEcho "EC addition with int CoefA"
else:
var b = P.x
b.mulCheckSparse(CoefA)
func sum[F](
r: var EllipticCurve[F],
P, Q: EllipticCurve[F],
CoefA: static F) =
r.sumImpl(P, Q, CoefA)
## ----------------------------------
const h2c_const_ec = QuadraticExt[BigInt[4]](
coords: [BigInt[4](raw: [uint64 1, 1, 1, 1]),
BigInt[4](raw: [uint64 1, 1, 1, 1])]
)
var P = EllipticCurve[QuadraticExt[BigInt[4]]](
x: QuadraticExt[BigInt[4]](
coords: [BigInt[4](raw: [uint64 1, 2, 3, 4]),
BigInt[4](raw: [uint64 1, 2, 3, 4])]
),
y: QuadraticExt[BigInt[4]](
coords: [BigInt[4](raw: [uint64 1, 2, 3, 4]),
BigInt[4](raw: [uint64 1, 2, 3, 4])]
),
z: QuadraticExt[BigInt[4]](
coords: [BigInt[4](raw: [uint64 1, 2, 3, 4]),
BigInt[4](raw: [uint64 1, 2, 3, 4])]
)
)
var Q = EllipticCurve[QuadraticExt[BigInt[4]]](
x: QuadraticExt[BigInt[4]](
coords: [BigInt[4](raw: [uint64 1, 2, 3, 4]),
BigInt[4](raw: [uint64 1, 2, 3, 4])]
),
y: QuadraticExt[BigInt[4]](
coords: [BigInt[4](raw: [uint64 1, 2, 3, 4]),
BigInt[4](raw: [uint64 1, 2, 3, 4])]
),
z: QuadraticExt[BigInt[4]](
coords: [BigInt[4](raw: [uint64 1, 2, 3, 4]),
BigInt[4](raw: [uint64 1, 2, 3, 4])]
)
)
var R: EllipticCurve[QuadraticExt[BigInt[4]]]
R.sum(P, Q, h2c_const_ec)
github-actions[bot]
mratsim
Araq
Original issue: https://github.com/mratsim/constantine/issues/373
It can be reproduced in its full environment with:
In the original issue, Nim v2.0.4 works but latest version-2-0 branch (v2.0.5) doesn't.
Now here is a single file reproduction. Surprisingly this fails on both Nim v2.0.4 and latest version-2-0