64 lines
2.4 KiB
Go
64 lines
2.4 KiB
Go
// Copyright (c) 2015-2021 The btcsuite developers
|
|
// Copyright (c) 2015-2021 The Decred developers
|
|
|
|
package btcec
|
|
|
|
import (
|
|
secp "github.com/decred/dcrd/dcrec/secp256k1/v4"
|
|
)
|
|
|
|
// JacobianPoint is an element of the group formed by the secp256k1 curve in
|
|
// Jacobian projective coordinates and thus represents a point on the curve.
|
|
type JacobianPoint = secp.JacobianPoint
|
|
|
|
// MakeJacobianPoint returns a Jacobian point with the provided X, Y, and Z
|
|
// coordinates.
|
|
func MakeJacobianPoint(x, y, z *FieldVal) JacobianPoint {
|
|
return secp.MakeJacobianPoint(x, y, z)
|
|
}
|
|
|
|
// AddNonConst adds the passed Jacobian points together and stores the result
|
|
// in the provided result param in *non-constant* time.
|
|
func AddNonConst(p1, p2, result *JacobianPoint) {
|
|
secp.AddNonConst(p1, p2, result)
|
|
}
|
|
|
|
// DecompressY attempts to calculate the Y coordinate for the given X
|
|
// coordinate such that the result pair is a point on the secp256k1 curve. It
|
|
// adjusts Y based on the desired oddness and returns whether or not it was
|
|
// successful since not all X coordinates are valid.
|
|
//
|
|
// The magnitude of the provided X coordinate field val must be a max of 8 for
|
|
// a correct result. The resulting Y field val will have a max magnitude of 2.
|
|
func DecompressY(x *FieldVal, odd bool, resultY *FieldVal) bool {
|
|
return secp.DecompressY(x, odd, resultY)
|
|
}
|
|
|
|
// DoubleNonConst doubles the passed Jacobian point and stores the result in
|
|
// the provided result parameter in *non-constant* time.
|
|
//
|
|
// NOTE: The point must be normalized for this function to return the correct
|
|
// result. The resulting point will be normalized.
|
|
func DoubleNonConst(p, result *JacobianPoint) {
|
|
secp.DoubleNonConst(p, result)
|
|
}
|
|
|
|
// ScalarBaseMultNonConst multiplies k*G where G is the base point of the group
|
|
// and k is a big endian integer. The result is stored in Jacobian coordinates
|
|
// (x1, y1, z1).
|
|
//
|
|
// NOTE: The resulting point will be normalized.
|
|
func ScalarBaseMultNonConst(k *ModNScalar, result *JacobianPoint) {
|
|
secp.ScalarBaseMultNonConst(k, result)
|
|
}
|
|
|
|
// ScalarMultNonConst multiplies k*P where k is a big endian integer modulo the
|
|
// curve order and P is a point in Jacobian projective coordinates and stores
|
|
// the result in the provided Jacobian point.
|
|
//
|
|
// NOTE: The point must be normalized for this function to return the correct
|
|
// result. The resulting point will be normalized.
|
|
func ScalarMultNonConst(k *ModNScalar, point, result *JacobianPoint) {
|
|
secp.ScalarMultNonConst(k, point, result)
|
|
}
|