arnaucube/go-iden3-crypto
1
0
Fork 0
mirror of https://github.com/arnaucube/go-iden3-crypto.git synced 2026-02-07 03:26:39 +01:00
Code Issues Packages Projects Releases Wiki Activity

MiMC7 finite field over R comprovation moved inside hash, same approach as Poseidon impl

Browse Source
This commit is contained in:
arnaucube
2019-08-30 11:58:10 +02:00
parent 0bac1c84ba
commit 2b1935299c
3 changed files with 26 additions and 103 deletions
Download Patch File Download Diff File Expand all files Collapse all files

60
mimc7/mimc7.go
View File

@@ -2,19 +2,16 @@ package mimc7
import (
"errors"
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/crypto"
_constants "github.com/iden3/go-iden3-crypto/constants"
"github.com/iden3/go-iden3-crypto/field"
"github.com/iden3/go-iden3-crypto/utils"
)
const SEED = "mimc"
// RElem is a big.Int of maximum 253 bits
type RElem *big.Int
var constants = generateConstantsData()
type constantsData struct {
@@ -45,36 +42,6 @@ func generateConstantsData() constantsData {
return constants
}
// BigIntToRElem checks if given big.Int fits in a Field R element, and returns the RElem type
func BigIntToRElem(a *big.Int) (RElem, error) {
if a.Cmp(constants.maxFieldVal) != -1 {
return RElem(a), errors.New("Given big.Int don't fits in the Finite Field over R")
}
return RElem(a), nil
}
//BigIntsToRElems converts from array of *big.Int to array of RElem
func BigIntsToRElems(arr []*big.Int) ([]RElem, error) {
o := make([]RElem, len(arr))
for i, a := range arr {
e, err := BigIntToRElem(a)
if err != nil {
return o, fmt.Errorf("element in position %v don't fits in Finite Field over R", i)
}
o[i] = e
}
return o, nil
}
// RElemsToBigInts converts from array of RElem to array of *big.Int
func RElemsToBigInts(arr []RElem) []*big.Int {
o := make([]*big.Int, len(arr))
for i, a := range arr {
o[i] = a
}
return o
}
func getConstants(fqR field.Fq, seed string, nRounds int) []*big.Int {
cts := make([]*big.Int, nRounds)
cts[0] = big.NewInt(int64(0))
@@ -88,7 +55,7 @@ func getConstants(fqR field.Fq, seed string, nRounds int) []*big.Int {
return cts
}
// MIMC7HashGeneric performs the MIMC7 hash over a RElem, in a generic way, where it can be specified the Finite Field over R, and the number of rounds
// MIMC7HashGeneric performs the MIMC7 hash over a *big.Int, in a generic way, where it can be specified the Finite Field over R, and the number of rounds
func MIMC7HashGeneric(fqR field.Fq, xIn, k *big.Int, nRounds int) *big.Int {
cts := getConstants(fqR, SEED, nRounds)
var r *big.Int
@@ -106,9 +73,11 @@ func MIMC7HashGeneric(fqR field.Fq, xIn, k *big.Int, nRounds int) *big.Int {
return fqR.Affine(fqR.Add(r, k))
}
// HashGeneric performs the MIMC7 hash over a RElem array, in a generic way, where it can be specified the Finite Field over R, and the number of rounds
func HashGeneric(iv *big.Int, arrEl []RElem, fqR field.Fq, nRounds int) (RElem, error) {
arr := RElemsToBigInts(arrEl)
// HashGeneric performs the MIMC7 hash over a *big.Int array, in a generic way, where it can be specified the Finite Field over R, and the number of rounds
func HashGeneric(iv *big.Int, arr []*big.Int, fqR field.Fq, nRounds int) (*big.Int, error) {
if !utils.CheckBigIntArrayInField(arr, constants.fqR.Q) {
return nil, errors.New("inputs values not inside Finite Field")
}
r := iv
var err error
for i := 0; i < len(arr); i++ {
@@ -117,10 +86,10 @@ func HashGeneric(iv *big.Int, arrEl []RElem, fqR field.Fq, nRounds int) (RElem,
return r, err
}
}
return RElem(r), nil
return r, nil
}
// MIMC7Hash performs the MIMC7 hash over a RElem, using the Finite Field over R and the number of rounds setted in the `constants` variable
// MIMC7Hash performs the MIMC7 hash over a *big.Int, using the Finite Field over R and the number of rounds setted in the `constants` variable
func MIMC7Hash(xIn, k *big.Int) *big.Int {
var r *big.Int
for i := 0; i < constants.nRounds; i++ {
@@ -137,16 +106,17 @@ func MIMC7Hash(xIn, k *big.Int) *big.Int {
return constants.fqR.Affine(constants.fqR.Add(r, k))
}
// Hash performs the MIMC7 hash over a RElem array
func Hash(arrEl []RElem, key *big.Int) RElem {
arr := RElemsToBigInts(arrEl)
// Hash performs the MIMC7 hash over a *big.Int array
func Hash(arr []*big.Int, key *big.Int) (*big.Int, error) {
if !utils.CheckBigIntArrayInField(arr, constants.fqR.Q) {
return nil, errors.New("inputs values not inside Finite Field")
}
var r *big.Int
if key == nil {
r = constants.fqR.Zero()
} else {
r = key
}
// r := constants.iv
for i := 0; i < len(arr); i++ {
r = constants.fqR.Add(
constants.fqR.Add(
@@ -155,5 +125,5 @@ func Hash(arrEl []RElem, key *big.Int) RElem {
),
MIMC7Hash(arr[i], r))
}
return RElem(r)
return r, nil
}