mirror of
https://github.com/arnaucube/go-iden3-crypto.git
synced 2026-02-07 11:36:41 +01:00
Optimize Poseidon
This commit is contained in:
Eduard S
@@ -6,8 +6,7 @@ import (
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"math/big"
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"strconv"
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_constants "github.com/iden3/go-iden3-crypto/constants"
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"github.com/iden3/go-iden3-crypto/field"
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"github.com/iden3/go-iden3-crypto/constants"
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"github.com/iden3/go-iden3-crypto/utils"
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"golang.org/x/crypto/blake2b"
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)
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@@ -17,23 +16,20 @@ const NROUNDSF = 8
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const NROUNDSP = 57
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const T = 6
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var constants = generateConstantsData()
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var constC []*big.Int
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var constM [T][T]*big.Int
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type constantsData struct {
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fqR field.Fq
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c []*big.Int
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m [][]*big.Int
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func Zero() *big.Int {
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return new(big.Int)
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}
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func generateConstantsData() constantsData {
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var constants constantsData
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func modQ(v *big.Int) {
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v.Mod(v, constants.Q)
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}
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fqR := field.NewFq(_constants.Q)
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constants.fqR = fqR
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constants.c = getPseudoRandom(fqR, SEED+"_constants", NROUNDSF+NROUNDSP)
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constants.m = getMDS(fqR)
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return constants
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func init() {
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constC = getPseudoRandom(SEED+"_constants", NROUNDSF+NROUNDSP)
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constM = getMDS()
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}
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func leByteArrayToBigInt(b []byte) *big.Int {
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@@ -45,14 +41,13 @@ func leByteArrayToBigInt(b []byte) *big.Int {
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return res
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}
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func getPseudoRandom(fqR field.Fq, seed string, n int) []*big.Int {
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var res []*big.Int
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func getPseudoRandom(seed string, n int) []*big.Int {
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res := make([]*big.Int, n)
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hash := blake2b.Sum256([]byte(seed))
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for len(res) < n {
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hashBigInt := new(big.Int)
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newN := fqR.Affine(utils.SetBigIntFromLEBytes(hashBigInt, hash[:]))
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// newN := fqR.Affine(leByteArrayToBigInt(hash[:]))
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res = append(res, newN)
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for i := 0; i < n; i++ {
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hashBigInt := Zero()
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res[i] = utils.SetBigIntFromLEBytes(hashBigInt, hash[:])
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modQ(res[i])
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hash = blake2b.Sum256(hash[:])
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}
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return res
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@@ -67,20 +62,20 @@ func nonceToString(n int) string {
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}
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// https://eprint.iacr.org/2019/458.pdf pag.8
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func getMDS(fqR field.Fq) [][]*big.Int {
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func getMDS() [T][T]*big.Int {
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nonce := 0
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cauchyMatrix := getPseudoRandom(fqR, SEED+"_matrix_"+nonceToString(nonce), T*2)
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cauchyMatrix := getPseudoRandom(SEED+"_matrix_"+nonceToString(nonce), T*2)
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for !checkAllDifferent(cauchyMatrix) {
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nonce += 1
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cauchyMatrix = getPseudoRandom(fqR, SEED+"_matrix_"+nonceToString(nonce), T*2)
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cauchyMatrix = getPseudoRandom(SEED+"_matrix_"+nonceToString(nonce), T*2)
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}
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var m [][]*big.Int
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var m [T][T]*big.Int
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for i := 0; i < T; i++ {
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var mi []*big.Int
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// var mi []*big.Int
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for j := 0; j < T; j++ {
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mi = append(mi, fqR.Inverse(fqR.Sub(cauchyMatrix[i], cauchyMatrix[T+j])))
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m[i][j] = new(big.Int).Sub(cauchyMatrix[i], cauchyMatrix[T+j])
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m[i][j].ModInverse(m[i][j], constants.Q)
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}
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m = append(m, mi)
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}
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return m
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}
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@@ -100,61 +95,64 @@ func checkAllDifferent(v []*big.Int) bool {
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}
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// ark computes Add-Round Key, from the paper https://eprint.iacr.org/2019/458.pdf
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func ark(state []*big.Int, c *big.Int) []*big.Int {
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func ark(state [T]*big.Int, c *big.Int) {
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for i := 0; i < T; i++ {
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state[i] = constants.fqR.Add(state[i], c)
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modQ(state[i].Add(state[i], c))
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}
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return state
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}
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// cubic performs x^5 mod p
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// https://eprint.iacr.org/2019/458.pdf page 8
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func cubic(a *big.Int) *big.Int {
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return constants.fqR.Mul(a, constants.fqR.Square(constants.fqR.Square(a)))
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var five = big.NewInt(5)
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func cubic(a *big.Int) {
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a.Exp(a, five, constants.Q)
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}
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// sbox https://eprint.iacr.org/2019/458.pdf page 6
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func sbox(state []*big.Int, i int) []*big.Int {
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func sbox(state [T]*big.Int, i int) {
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if (i < NROUNDSF/2) || (i >= NROUNDSF/2+NROUNDSP) {
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for j := 0; j < T; j++ {
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state[j] = cubic(state[j])
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cubic(state[j])
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}
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} else {
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state[0] = cubic(state[0])
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cubic(state[0])
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}
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return state
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}
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// mix returns [[matrix]] * [vector]
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func mix(state []*big.Int, m [][]*big.Int) []*big.Int {
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var newState []*big.Int
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for i := 0; i < len(state); i++ {
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newState = append(newState, constants.fqR.Zero())
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for j := 0; j < len(state); j++ {
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newState[i] = constants.fqR.Add(newState[i], constants.fqR.Mul(m[i][j], state[j]))
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func mix(state [T]*big.Int, newState [T]*big.Int, m [T][T]*big.Int) {
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mul := Zero()
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for i := 0; i < T; i++ {
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newState[i].SetInt64(0)
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for j := 0; j < T; j++ {
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modQ(mul.Mul(m[i][j], state[j]))
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newState[i].Add(newState[i], mul)
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}
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modQ(newState[i])
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}
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return newState
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}
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// PoseidonHash computes the Poseidon hash for the given inputs
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func PoseidonHash(inp []*big.Int) (*big.Int, error) {
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if len(inp) == 0 || len(inp) > T {
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return nil, errors.New("wrong inputs length")
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}
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if !utils.CheckBigIntArrayInField(inp, constants.fqR.Q) {
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func PoseidonHash(inp [T]*big.Int) (*big.Int, error) {
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if !utils.CheckBigIntArrayInField(inp[:], constants.Q) {
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return nil, errors.New("inputs values not inside Finite Field")
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}
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state := inp
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for i := len(inp); i < T; i++ {
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state = append(state, constants.fqR.Zero())
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state := [T]*big.Int{}
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for i := 0; i < T; i++ {
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state[i] = new(big.Int).Set(inp[i])
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}
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// ARK --> SBox --> M, https://eprint.iacr.org/2019/458.pdf pag.5
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var newState [T]*big.Int
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for i := 0; i < T; i++ {
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newState[i] = Zero()
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}
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for i := 0; i < NROUNDSF+NROUNDSP; i++ {
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state = ark(state, constants.c[i])
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state = sbox(state, i)
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state = mix(state, constants.m)
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ark(state, constC[i])
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sbox(state, i)
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mix(state, newState, constM)
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state, newState = newState, state
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}
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return state[0], nil
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}
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@@ -162,28 +160,31 @@ func PoseidonHash(inp []*big.Int) (*big.Int, error) {
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// Hash performs the Poseidon hash over a *big.Int array
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// in chunks of 5 elements
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func Hash(arr []*big.Int) (*big.Int, error) {
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if !utils.CheckBigIntArrayInField(arr, constants.fqR.Q) {
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if !utils.CheckBigIntArrayInField(arr, constants.Q) {
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return nil, errors.New("inputs values not inside Finite Field")
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}
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r := constants.fqR.Zero()
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r := big.NewInt(1)
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for i := 0; i < len(arr); i = i + T - 1 {
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var toHash [T]*big.Int
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for j := 0; j < T-1; j++ {
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if i+j < len(arr) {
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toHash[j] = arr[i+j]
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} else {
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toHash[j] = _constants.Zero
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j := 0
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for ; j < T-1; j++ {
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if i+j >= len(arr) {
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break
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}
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toHash[j] = arr[i+j]
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}
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toHash[T-1] = r
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ph, err := PoseidonHash(toHash[:])
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toHash[j] = r
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j++
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for ; j < T; j++ {
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toHash[j] = constants.Zero
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}
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ph, err := PoseidonHash(toHash)
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if err != nil {
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return nil, err
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}
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r = constants.fqR.Add(
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r,
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ph)
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modQ(r.Add(r, ph))
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}
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return r, nil
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@@ -195,12 +196,12 @@ func HashBytes(b []byte) (*big.Int, error) {
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n := 31
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bElems := make([]*big.Int, 0, len(b)/n+1)
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for i := 0; i < len(b)/n; i++ {
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v := new(big.Int)
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v := Zero()
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utils.SetBigIntFromLEBytes(v, b[n*i:n*(i+1)])
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bElems = append(bElems, v)
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}
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if len(b)%n != 0 {
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v := new(big.Int)
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v := Zero()
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utils.SetBigIntFromLEBytes(v, b[(len(b)/n)*n:])
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bElems = append(bElems, v)
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}
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