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homomorphicpedersencommit.go
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/
homomorphicpedersencommit.go
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package homomorphicpedersencommit
import (
"github.com/jadeydi/jubjub/pkg/grouphash"
"github.com/jadeydi/jubjub/pkg/jubjub"
"github.com/jadeydi/jubjub/pkg/pedersenhash"
"math/big"
)
var (
domain = []byte("Zcash_PH")
)
type HomomorphicPedersenCommitter struct {
curve *jubjub.Jubjub
groupHasher *grouphash.GroupHasher
pedersenHasher *pedersenhash.PedersenHasher
}
func NewCommitter() (*HomomorphicPedersenCommitter, error) {
j := jubjub.NewJubjub()
groupHasher, err := grouphash.NewGroupHasher([]byte("Zcash_cv"))
if err != nil {
return nil, err
}
pedersenHasher, err := pedersenhash.NewPedersenHasher()
if err != nil {
return nil, err
}
return &HomomorphicPedersenCommitter{
curve: j,
groupHasher: groupHasher,
pedersenHasher:pedersenHasher,
}, nil
}
func (committer *HomomorphicPedersenCommitter) Commit(v *big.Int, rcv *big.Int) (*jubjub.JubjubPoint, error) {
vBase, err := committer.groupHasher.FindGroupHash([]byte("v"))
if err != nil {
return nil, err
}
vSide, err := committer.curve.ScalarMult(v, vBase)
if err != nil {
return nil, err
}
rBase, err := committer.groupHasher.FindGroupHash([]byte("r"))
if err != nil {
return nil, err
}
rSide, err := committer.curve.ScalarMult(rcv, rBase)
if err != nil {
return nil, err
}
ret, err := committer.curve.Add(vSide, rSide)
if err != nil {
return nil, err
}
return ret, nil
}