mimc7 over bn254 baybyjubjub

emulated/bn254/twistededwards/mimc7/constants.go

@@ -0,0 +1,122 @@
+package mimc7
+
+import (
+	"math/big"
+
+	"github.com/consensys/gnark/std/algebra/emulated/sw_bn254"
+	"github.com/consensys/gnark/std/math/emulated"
+)
+
+const nRounds = 91
+
+var (
+	q         emulated.Element[sw_bn254.ScalarField]
+	constants []emulated.Element[sw_bn254.ScalarField]
+)
+
+func init() {
+	biQ, _ := new(big.Int).SetString("21888242871839275222246405745257275088548364400416034343698204186575808495617", 10)
+	q = emulated.ValueOf[sw_bn254.ScalarField](biQ)
+
+	constants = make([]emulated.Element[sw_bn254.ScalarField], nRounds)
+	for i := 1; i < nRounds; i++ {
+		contstant, _ := new(big.Int).SetString(strConstants[i-1], 10)
+		constants[i] = emulated.ValueOf[sw_bn254.ScalarField](contstant)
+	}
+}
+
+// strConstants contains the constants for the encryption rounds, they were
+// generated the method generateConstatsData of iden3 mimc7 implementation:
+// https://github.com/iden3/go-iden3-crypto/blob/master/mimc7/mimc7.go
+var strConstants = []string{
+	"20888961410941983456478427210666206549300505294776164667214940546594746570981",
+	"15265126113435022738560151911929040668591755459209400716467504685752745317193",
+	"8334177627492981984476504167502758309043212251641796197711684499645635709656",
+	"1374324219480165500871639364801692115397519265181803854177629327624133579404",
+	"11442588683664344394633565859260176446561886575962616332903193988751292992472",
+	"2558901189096558760448896669327086721003508630712968559048179091037845349145",
+	"11189978595292752354820141775598510151189959177917284797737745690127318076389",
+	"3262966573163560839685415914157855077211340576201936620532175028036746741754",
+	"17029914891543225301403832095880481731551830725367286980611178737703889171730",
+	"4614037031668406927330683909387957156531244689520944789503628527855167665518",
+	"19647356996769918391113967168615123299113119185942498194367262335168397100658",
+	"5040699236106090655289931820723926657076483236860546282406111821875672148900",
+	"2632385916954580941368956176626336146806721642583847728103570779270161510514",
+	"17691411851977575435597871505860208507285462834710151833948561098560743654671",
+	"11482807709115676646560379017491661435505951727793345550942389701970904563183",
+	"8360838254132998143349158726141014535383109403565779450210746881879715734773",
+	"12663821244032248511491386323242575231591777785787269938928497649288048289525",
+	"3067001377342968891237590775929219083706800062321980129409398033259904188058",
+	"8536471869378957766675292398190944925664113548202769136103887479787957959589",
+	"19825444354178182240559170937204690272111734703605805530888940813160705385792",
+	"16703465144013840124940690347975638755097486902749048533167980887413919317592",
+	"13061236261277650370863439564453267964462486225679643020432589226741411380501",
+	"10864774797625152707517901967943775867717907803542223029967000416969007792571",
+	"10035653564014594269791753415727486340557376923045841607746250017541686319774",
+	"3446968588058668564420958894889124905706353937375068998436129414772610003289",
+	"4653317306466493184743870159523234588955994456998076243468148492375236846006",
+	"8486711143589723036499933521576871883500223198263343024003617825616410932026",
+	"250710584458582618659378487568129931785810765264752039738223488321597070280",
+	"2104159799604932521291371026105311735948154964200596636974609406977292675173",
+	"16313562605837709339799839901240652934758303521543693857533755376563489378839",
+	"6032365105133504724925793806318578936233045029919447519826248813478479197288",
+	"14025118133847866722315446277964222215118620050302054655768867040006542798474",
+	"7400123822125662712777833064081316757896757785777291653271747396958201309118",
+	"1744432620323851751204287974553233986555641872755053103823939564833813704825",
+	"8316378125659383262515151597439205374263247719876250938893842106722210729522",
+	"6739722627047123650704294650168547689199576889424317598327664349670094847386",
+	"21211457866117465531949733809706514799713333930924902519246949506964470524162",
+	"13718112532745211817410303291774369209520657938741992779396229864894885156527",
+	"5264534817993325015357427094323255342713527811596856940387954546330728068658",
+	"18884137497114307927425084003812022333609937761793387700010402412840002189451",
+	"5148596049900083984813839872929010525572543381981952060869301611018636120248",
+	"19799686398774806587970184652860783461860993790013219899147141137827718662674",
+	"19240878651604412704364448729659032944342952609050243268894572835672205984837",
+	"10546185249390392695582524554167530669949955276893453512788278945742408153192",
+	"5507959600969845538113649209272736011390582494851145043668969080335346810411",
+	"18177751737739153338153217698774510185696788019377850245260475034576050820091",
+	"19603444733183990109492724100282114612026332366576932662794133334264283907557",
+	"10548274686824425401349248282213580046351514091431715597441736281987273193140",
+	"1823201861560942974198127384034483127920205835821334101215923769688644479957",
+	"11867589662193422187545516240823411225342068709600734253659804646934346124945",
+	"18718569356736340558616379408444812528964066420519677106145092918482774343613",
+	"10530777752259630125564678480897857853807637120039176813174150229243735996839",
+	"20486583726592018813337145844457018474256372770211860618687961310422228379031",
+	"12690713110714036569415168795200156516217175005650145422920562694422306200486",
+	"17386427286863519095301372413760745749282643730629659997153085139065756667205",
+	"2216432659854733047132347621569505613620980842043977268828076165669557467682",
+	"6309765381643925252238633914530877025934201680691496500372265330505506717193",
+	"20806323192073945401862788605803131761175139076694468214027227878952047793390",
+	"4037040458505567977365391535756875199663510397600316887746139396052445718861",
+	"19948974083684238245321361840704327952464170097132407924861169241740046562673",
+	"845322671528508199439318170916419179535949348988022948153107378280175750024",
+	"16222384601744433420585982239113457177459602187868460608565289920306145389382",
+	"10232118865851112229330353999139005145127746617219324244541194256766741433339",
+	"6699067738555349409504843460654299019000594109597429103342076743347235369120",
+	"6220784880752427143725783746407285094967584864656399181815603544365010379208",
+	"6129250029437675212264306655559561251995722990149771051304736001195288083309",
+	"10773245783118750721454994239248013870822765715268323522295722350908043393604",
+	"4490242021765793917495398271905043433053432245571325177153467194570741607167",
+	"19596995117319480189066041930051006586888908165330319666010398892494684778526",
+	"837850695495734270707668553360118467905109360511302468085569220634750561083",
+	"11803922811376367215191737026157445294481406304781326649717082177394185903907",
+	"10201298324909697255105265958780781450978049256931478989759448189112393506592",
+	"13564695482314888817576351063608519127702411536552857463682060761575100923924",
+	"9262808208636973454201420823766139682381973240743541030659775288508921362724",
+	"173271062536305557219323722062711383294158572562695717740068656098441040230",
+	"18120430890549410286417591505529104700901943324772175772035648111937818237369",
+	"20484495168135072493552514219686101965206843697794133766912991150184337935627",
+	"19155651295705203459475805213866664350848604323501251939850063308319753686505",
+	"11971299749478202793661982361798418342615500543489781306376058267926437157297",
+	"18285310723116790056148596536349375622245669010373674803854111592441823052978",
+	"7069216248902547653615508023941692395371990416048967468982099270925308100727",
+	"6465151453746412132599596984628739550147379072443683076388208843341824127379",
+	"16143532858389170960690347742477978826830511669766530042104134302796355145785",
+	"19362583304414853660976404410208489566967618125972377176980367224623492419647",
+	"1702213613534733786921602839210290505213503664731919006932367875629005980493",
+	"10781825404476535814285389902565833897646945212027592373510689209734812292327",
+	"4212716923652881254737947578600828255798948993302968210248673545442808456151",
+	"7594017890037021425366623750593200398174488805473151513558919864633711506220",
+	"18979889247746272055963929241596362599320706910852082477600815822482192194401",
+	"13602139229813231349386885113156901793661719180900395818909719758150455500533",
+}

emulated/bn254/twistededwards/mimc7/mimc.go

@@ -0,0 +1,75 @@
+package mimc7
+
+import (
+	"github.com/consensys/gnark/frontend"
+	"github.com/consensys/gnark/std/algebra/emulated/sw_bn254"
+	"github.com/consensys/gnark/std/math/emulated"
+)
+
+type MiMC struct {
+	params []emulated.Element[sw_bn254.ScalarField] // slice containing constants for the encryption rounds
+	h      emulated.Element[sw_bn254.ScalarField]   // current vector in the Miyaguchi–Preneel scheme
+	data   []emulated.Element[sw_bn254.ScalarField] // state storage. data is updated when Write() is called. Sum sums the data.
+	field  *emulated.Field[sw_bn254.ScalarField]
+}
+
+// NewMiMC function returns a initialized MiMC hash function into the BabyJubJub
+// curve for the emulated BN254 ScalarField.
+func NewMiMC(api frontend.API) (MiMC, error) {
+	field, err := emulated.NewField[sw_bn254.ScalarField](api)
+	if err != nil {
+		return MiMC{}, err
+	}
+	return MiMC{
+		params: constants,
+		h:      emulated.ValueOf[sw_bn254.ScalarField](nil),
+		field:  field,
+	}, nil
+}
+
+// Write adds more data to the running hash.
+func (h *MiMC) Write(data ...emulated.Element[sw_bn254.ScalarField]) {
+	h.data = append(h.data, data...)
+}
+
+// Reset resets the Hash to its initial state.
+func (h *MiMC) Reset() {
+	h.data = nil
+	h.h = emulated.ValueOf[sw_bn254.ScalarField](nil)
+}
+
+// Sum hash using [Miyaguchi–Preneel] where the XOR operation is replaced by
+// field addition.
+func (h *MiMC) Sum() emulated.Element[sw_bn254.ScalarField] {
+	for _, stream := range h.data {
+		r := h.encrypt(stream)
+		h.h = *h.field.Add(&h.h, &r)
+		h.h = *h.field.ModAdd(&h.h, &stream, &q)
+	}
+	h.data = nil // flush the data already hashed
+	return h.h
+}
+
+// AssertSumIsEqual asserts that the hash of the data is equal to the expected
+// hash.
+func (h *MiMC) AssertSumIsEqual(expected emulated.Element[sw_bn254.ScalarField]) {
+	res := h.Sum()
+	h.field.AssertIsEqual(&res, &expected)
+}
+
+func (h *MiMC) pow7(x emulated.Element[sw_bn254.ScalarField]) emulated.Element[sw_bn254.ScalarField] {
+	x2 := h.field.Mul(&x, &x)
+	x3 := h.field.Mul(x2, &x)
+	x5 := h.field.Mul(x2, x3)
+	return *h.field.Mul(x2, x5)
+}
+
+func (h *MiMC) encrypt(m emulated.Element[sw_bn254.ScalarField]) emulated.Element[sw_bn254.ScalarField] {
+	x := m
+	for i := 0; i < nRounds; i++ {
+		sum := h.field.Add(&x, &h.h)
+		sum = h.field.Add(sum, &h.params[i])
+		x = h.pow7(*sum)
+	}
+	return *h.field.Add(&x, &h.h)
+}

emulated/bn254/twistededwards/mimc7/mimc_test.go

@@ -0,0 +1,46 @@
+package mimc7
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/consensys/gnark-crypto/ecc"
+	"github.com/consensys/gnark/backend"
+	"github.com/consensys/gnark/frontend"
+	"github.com/consensys/gnark/std/algebra/emulated/sw_bn254"
+	"github.com/consensys/gnark/std/math/emulated"
+	"github.com/consensys/gnark/test"
+	qt "github.com/frankban/quicktest"
+	"github.com/iden3/go-iden3-crypto/mimc7"
+)
+
+type testMiMCCircuit struct {
+	Hash     emulated.Element[sw_bn254.ScalarField] `gnark:",public"`
+	Preimage emulated.Element[sw_bn254.ScalarField]
+}
+
+func (circuit *testMiMCCircuit) Define(api frontend.API) error {
+	mimc, err := NewMiMC(api)
+	if err != nil {
+		return err
+	}
+	mimc.Write(circuit.Preimage)
+	mimc.AssertSumIsEqual(circuit.Hash)
+	return nil
+}
+
+func TestMiMC(t *testing.T) {
+	c := qt.New(t)
+	// generate a random input and hash it
+	input := new(big.Int).SetInt64(12)
+	hash, err := mimc7.Hash([]*big.Int{input}, nil)
+	c.Assert(err, qt.IsNil)
+	// create a witness
+	witness := testMiMCCircuit{
+		Preimage: emulated.ValueOf[sw_bn254.ScalarField](input),
+		Hash:     emulated.ValueOf[sw_bn254.ScalarField](hash),
+	}
+	// run the test
+	assert := test.NewAssert(t)
+	assert.SolvingSucceeded(&testMiMCCircuit{}, &witness, test.WithCurves(ecc.BLS12_377), test.WithBackends(backend.GROTH16))
+}