mirror of
https://github.com/go-gitea/gitea
synced 2024-12-21 11:14:39 +01:00
274149dd14
* Switch to keybase go-crypto (for some elliptic curve key) + test
* Use assert.NoError
and add a little more context to failing test description
* Use assert.(No)Error everywhere 🌈
and assert.Error in place of .Nil/.NotNil
83 lines
2 KiB
Go
83 lines
2 KiB
Go
package brainpool
|
|
|
|
import (
|
|
"crypto/elliptic"
|
|
"math/big"
|
|
)
|
|
|
|
var _ elliptic.Curve = (*rcurve)(nil)
|
|
|
|
type rcurve struct {
|
|
twisted elliptic.Curve
|
|
params *elliptic.CurveParams
|
|
z *big.Int
|
|
zinv *big.Int
|
|
z2 *big.Int
|
|
z3 *big.Int
|
|
zinv2 *big.Int
|
|
zinv3 *big.Int
|
|
}
|
|
|
|
var (
|
|
two = big.NewInt(2)
|
|
three = big.NewInt(3)
|
|
)
|
|
|
|
func newrcurve(twisted elliptic.Curve, params *elliptic.CurveParams, z *big.Int) *rcurve {
|
|
zinv := new(big.Int).ModInverse(z, params.P)
|
|
return &rcurve{
|
|
twisted: twisted,
|
|
params: params,
|
|
z: z,
|
|
zinv: zinv,
|
|
z2: new(big.Int).Exp(z, two, params.P),
|
|
z3: new(big.Int).Exp(z, three, params.P),
|
|
zinv2: new(big.Int).Exp(zinv, two, params.P),
|
|
zinv3: new(big.Int).Exp(zinv, three, params.P),
|
|
}
|
|
}
|
|
|
|
func (curve *rcurve) toTwisted(x, y *big.Int) (*big.Int, *big.Int) {
|
|
var tx, ty big.Int
|
|
tx.Mul(x, curve.z2)
|
|
tx.Mod(&tx, curve.params.P)
|
|
ty.Mul(y, curve.z3)
|
|
ty.Mod(&ty, curve.params.P)
|
|
return &tx, &ty
|
|
}
|
|
|
|
func (curve *rcurve) fromTwisted(tx, ty *big.Int) (*big.Int, *big.Int) {
|
|
var x, y big.Int
|
|
x.Mul(tx, curve.zinv2)
|
|
x.Mod(&x, curve.params.P)
|
|
y.Mul(ty, curve.zinv3)
|
|
y.Mod(&y, curve.params.P)
|
|
return &x, &y
|
|
}
|
|
|
|
func (curve *rcurve) Params() *elliptic.CurveParams {
|
|
return curve.params
|
|
}
|
|
|
|
func (curve *rcurve) IsOnCurve(x, y *big.Int) bool {
|
|
return curve.twisted.IsOnCurve(curve.toTwisted(x, y))
|
|
}
|
|
|
|
func (curve *rcurve) Add(x1, y1, x2, y2 *big.Int) (x, y *big.Int) {
|
|
tx1, ty1 := curve.toTwisted(x1, y1)
|
|
tx2, ty2 := curve.toTwisted(x2, y2)
|
|
return curve.fromTwisted(curve.twisted.Add(tx1, ty1, tx2, ty2))
|
|
}
|
|
|
|
func (curve *rcurve) Double(x1, y1 *big.Int) (x, y *big.Int) {
|
|
return curve.fromTwisted(curve.twisted.Double(curve.toTwisted(x1, y1)))
|
|
}
|
|
|
|
func (curve *rcurve) ScalarMult(x1, y1 *big.Int, scalar []byte) (x, y *big.Int) {
|
|
tx1, ty1 := curve.toTwisted(x1, y1)
|
|
return curve.fromTwisted(curve.twisted.ScalarMult(tx1, ty1, scalar))
|
|
}
|
|
|
|
func (curve *rcurve) ScalarBaseMult(scalar []byte) (x, y *big.Int) {
|
|
return curve.fromTwisted(curve.twisted.ScalarBaseMult(scalar))
|
|
}
|