Prad Nukala 807b2e86ec
feature/1220 origin handle exists method (#1241)
* feat: add docs and CI workflow for publishing to onsonr.dev

* (refactor): Move hway,motr executables to their own repos

* feat: simplify devnet and testnet configurations

* refactor: update import path for didcrypto package

* docs(networks): Add README with project overview, architecture, and community links

* refactor: Move network configurations to deploy directory

* build: update golang version to 1.23

* refactor: move logger interface to appropriate package

* refactor: Move devnet configuration to networks/devnet

* chore: improve release process with date variable

* (chore): Move Crypto Library

* refactor: improve code structure and readability in DID module

* feat: integrate Trunk CI checks

* ci: optimize CI workflow by removing redundant build jobs

---------

Co-authored-by: Darp Alakun <i@prad.nu>
2025-01-06 17:06:10 +00:00

83 lines
2.7 KiB
Go
Executable File

package native
// SswuParams for computing the Simplified SWU mapping
// for hash to curve implementations
type SswuParams struct {
C1, C2, A, B, Z [FieldLimbs]uint64
}
// Osswu3mod4 computes the simplified map optmized for 3 mod 4 primes
// https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-11#appendix-G.2.1
func (p *SswuParams) Osswu3mod4(u *Field) (x, y *Field) {
var tv1, tv2, tv3, tv4, xd, x1n, x2n, gxd, gx1, aNeg, zA, y1, y2 [FieldLimbs]uint64
var wasInverted int
u.Arithmetic.Mul(&tv1, &u.Value, &u.Value) // tv1 = u^2
u.Arithmetic.Mul(&tv3, &p.Z, &tv1) // tv3 = z * tv1
u.Arithmetic.Square(&tv2, &tv3) // tv2 = tv3^2
u.Arithmetic.Add(&xd, &tv2, &tv3) // xd = tv2 + tv3
u.Arithmetic.Add(&x1n, &u.Params.R, &xd) // x1n = (xd + 1)
u.Arithmetic.Mul(&x1n, &x1n, &p.B) // x1n * B
u.Arithmetic.Neg(&aNeg, &p.A)
u.Arithmetic.Mul(&xd, &xd, &aNeg) // xd = -A * xd
xdIsZero := (&Field{
Value: xd,
}).IsZero()
u.Arithmetic.Mul(&zA, &p.Z, &p.A)
u.Arithmetic.Selectznz(&xd, &xd, &zA, xdIsZero) // xd = z * A if xd == 0
u.Arithmetic.Square(&tv2, &xd) // tv2 = xd^2
u.Arithmetic.Mul(&gxd, &tv2, &xd) // gxd = tv2 * xd
u.Arithmetic.Mul(&tv2, &tv2, &p.A) // tv2 = A * tv2
u.Arithmetic.Square(&gx1, &x1n) // gx1 = x1n^2
u.Arithmetic.Add(&gx1, &gx1, &tv2) // gx1 = gx1 + tv2
u.Arithmetic.Mul(&gx1, &gx1, &x1n) // gx1 = gx1 * x1n
u.Arithmetic.Mul(&tv2, &gxd, &p.B) // tv2 = B * gxd
u.Arithmetic.Add(&gx1, &gx1, &tv2) // gx1 = gx1 + tv2
u.Arithmetic.Square(&tv4, &gxd) // tv4 = gxd^2
u.Arithmetic.Mul(&tv2, &gx1, &gxd) // tv2 = gx1 * gxd
u.Arithmetic.Mul(&tv4, &tv4, &tv2) // tv4 = tv4 * tv2
Pow(&y1, &tv4, &p.C1, u.Params, u.Arithmetic) // y1 = tv4^C1
u.Arithmetic.Mul(&y1, &y1, &tv2) //y1 = y1 * tv2
u.Arithmetic.Mul(&x2n, &tv3, &x1n) // x2n = tv3 * x1n
u.Arithmetic.Mul(&y2, &y1, &p.C2) // y2 = y1 * c2
u.Arithmetic.Mul(&y2, &y2, &tv1) // y2 = y2 * tv1
u.Arithmetic.Mul(&y2, &y2, &u.Value) // y2 = y2 * u
u.Arithmetic.Square(&tv2, &y1) // tv2 = y1^2
u.Arithmetic.Mul(&tv2, &tv2, &gxd) // tv2 = tv2 * gxd
e2 := (&Field{Value: tv2}).Equal(&Field{Value: gx1})
x = new(Field).Set(u)
y = new(Field).Set(u)
// If e2, x = x1, else x = x2
u.Arithmetic.Selectznz(&x.Value, &x2n, &x1n, e2)
// xn / xd
u.Arithmetic.Invert(&wasInverted, &tv1, &xd)
u.Arithmetic.Mul(&tv1, &x.Value, &tv1)
u.Arithmetic.Selectznz(&x.Value, &x.Value, &tv1, wasInverted)
// If e2, y = y1, else y = y2
u.Arithmetic.Selectznz(&y.Value, &y2, &y1, e2)
uBytes := u.Bytes()
yBytes := y.Bytes()
usign := uBytes[0] & 1
ysign := yBytes[0] & 1
// Fix sign of y
if usign != ysign {
y.Neg(y)
}
return
}