Replace mimc round constants (up to 93 rounds)

client/zeth/core/mimc.py

@@ -7,6 +7,7 @@
 from Crypto.Hash import keccak \
     # pylint: disable=import-error,no-name-in-module,line-too-long  #type: ignore
 from abc import abstractmethod
+from typing import List
 
 # Reference papers:
 #
@@ -117,6 +118,23 @@ def __init__(self, seed_str: str = MIMC_MT_SEED):
             62)
 
 
+def generate_round_constants(seed_str: str, num_rounds: int) -> List[int]:
+    """
+    Return the first `num_rounds` round constants. Not called directly here,
+    but used to precompute (in particular for the mimc_permutation gadget).
+    """
+    seed = _keccak_256(_str_to_bytes(seed_str))
+    rc = seed
+
+    rcs = [0]
+    for _ in range(1, num_rounds):
+        rc = _update_round_constant(rc)
+        rcs.append(rc)
+
+    assert len(rcs) == num_rounds
+    return rcs
+
+
 def get_tree_hash_for_pairing(pairing_name: str) -> ITreeHash:
     """
     Select an appropriate hash for a given pairing. Note that these must match

libzeth/circuits/mimc/mimc_permutation.hpp

@@ -20,8 +20,11 @@ template<typename FieldT, size_t Exponent, size_t NumRounds>
 class MiMC_permutation_gadget : public libsnark::gadget<FieldT>
 {
 private:
-    // Round constants only available up to some maximum number of rounds
-    static const size_t MaxRounds = 65;
+    // Round constants only available up to some maximum number of rounds. Note
+    // that the instantiations used in this library do not use all 93 round
+    // constants, but other instantiations may (in particular, see
+    // instantations for other curves in https://github.com/clearmatics/zecale).
+    static const size_t MaxRounds = 93;
     static_assert(
         NumRounds <= MaxRounds, "NumRounds must be less than MaxRounds");
 

libzeth/circuits/mimc/mimc_permutation.tcc

@@ -155,145 +155,112 @@ void MiMC_permutation_gadget<FieldT, Exponent, NumRounds>::
         return;
     }
 
-    // For simplicity, always generate constants for MaxRounds.
-    round_constants.reserve(MaxRounds);
+    // Constants are generated as follows (in client python env):
+    // (env) $ python
+    // >>> import zeth.core.mimc as mimc
+    // >>> import zeth.core.constants as constants
+    // >>> mimc.generate_round_constants(constants.MIMC_MT_SEED, 93)
 
     // The constant is set to "0" in the first round of MiMC permutation (see:
     // https://eprint.iacr.org/2016/492.pdf)
-    round_constants.push_back(FieldT("0"));
 
+    // For simplicity, always populate with enough constants for MaxRounds.
     // clang-format off
-
-    // This is sha3_256(sha3_256("clearmatics_mt_seed"))
-    round_constants.push_back(FieldT(
-        "22159019873790129476324495190496603411493310235845550845393361088354059025587"));
-
-    round_constants.push_back(FieldT(
-        "27761654615899466766976328798614662221520122127418767386594587425934055859027"));
-    round_constants.push_back(FieldT(
-        "94824950344308939111646914673652476426466554475739520071212351703914847519222"));
-    round_constants.push_back(FieldT(
-        "84875755167904490740680810908425347913240786521935721949482414218097022905238"));
-    round_constants.push_back(FieldT(
-        "103827469404022738626089808362855974444473512881791722903435218437949312500276"));
-    round_constants.push_back(FieldT(
-        "79151333313630310680682684119244096199179603958178503155035988149812024220238"));
-    round_constants.push_back(FieldT(
-        "69032546029442066350494866745598303896748709048209836077355812616627437932521"));
-    round_constants.push_back(FieldT(
-        "71828934229806034323678289655618358926823037947843672773514515549250200395747"));
-    round_constants.push_back(FieldT(
-        "20380360065304068228640594346624360147706079921816528167847416754157399404427"));
-    round_constants.push_back(FieldT(
-        "33389882590456326015242966586990383840423378222877476683761799984554709177407"));
-    round_constants.push_back(FieldT(
-        "50122810070778420844700285367936543284029126632619100118638682958218725318756"));
-    round_constants.push_back(FieldT(
-        "49246859699528342369154520789249265070136349803358469088610922925489948122588"));
-    round_constants.push_back(FieldT(
-        "42301293999667742503298132605205313473294493780037112351216393454277775233701"));
-    round_constants.push_back(FieldT(
-        "84114918321547685007627041787929288135785026882582963701427252073231899729239"));
-    round_constants.push_back(FieldT(
-        "62442564517333183431281494169332072638102772915973556148439397377116238052032"));
-    round_constants.push_back(FieldT(
-        "90371696767943970492795296318744142024828099537644566050263944542077360454000"));
-    round_constants.push_back(FieldT(
-        "115430938798103259020685569971731347341632428718094375123887258419895353452385"));
-    round_constants.push_back(FieldT(
-        "113486567655643015051612432235944767094037016028918659325405959747202187788641"));
-    round_constants.push_back(FieldT(
-        "42521224046978113548086179860571260859679910353297292895277062016640527060158"));
-    round_constants.push_back(FieldT(
-        "59337418021535832349738836949730504849571827921681387254433920345654363097721"));
-    round_constants.push_back(FieldT(
-        "11312792726948192147047500338922194498305047686482578113645836215734847502787"));
-    round_constants.push_back(FieldT(
-        "5531104903388534443968883334496754098135862809700301013033503341381689618972"));
-    round_constants.push_back(FieldT(
-        "67267967506593457603372921446668397713655666818276613345969561709158934132467"));
-    round_constants.push_back(FieldT(
-        "14150601882795046585170507190892504128795190437985555320824531798948976631295"));
-    round_constants.push_back(FieldT(
-        "85062650450907709431728516509140931676564801299509460081586249478375415684322"));
-    round_constants.push_back(FieldT(
-        "3190636703526705373452173482292964566521687248139217048214149162895182633187"));
-    round_constants.push_back(FieldT(
-        "94697707246459731032848302079578714910941380385884087153796554334872238022178"));
-    round_constants.push_back(FieldT(
-        "105237079024348272465679804525604310926083869213267017956044692586513087552889"));
-    round_constants.push_back(FieldT(
-        "107666297462370279081061498341391155289817553443536637437225808625028106164694"));
-    round_constants.push_back(FieldT(
-        "50658185643016152702409617752847261961811370146977869351531768522548888496960"));
-    round_constants.push_back(FieldT(
-        "40194505239242861003888376856216043830225436269588275639840138989648733836164"));
-    round_constants.push_back(FieldT(
-        "18446023938001439123322925291203176968088321100216399802351969471087090508798"));
-    round_constants.push_back(FieldT(
-        "56716868411561319312404565555682857409226456576794830238428782927207680423406"));
-    round_constants.push_back(FieldT(
-        "99446603622401702299467002115709680008186357666919726252089514718382895122907"));
-    round_constants.push_back(FieldT(
-        "14440268383603206763216449941954085575335212955165966039078057319953582173633"));
-    round_constants.push_back(FieldT(
-        "19800531992512132732080265836821627955799468140051158794892004229352040429024"));
-    round_constants.push_back(FieldT(
-        "105297016338495372394147178784104774655759157445835217996114870903812070518445"));
-    round_constants.push_back(FieldT(
-        "25603899274511343521079846952994517772529013612481201245155078199291999403355"));
-    round_constants.push_back(FieldT(
-        "42343992762533961606462320250264898254257373842674711124109812370529823212221"));
-    round_constants.push_back(FieldT(
-        "10746157796797737664081586165620034657529089112211072426663365617141344936203"));
-    round_constants.push_back(FieldT(
-        "83415911130754382252267592583976834889211427666721691843694426391396310581540"));
-    round_constants.push_back(FieldT(
-        "90866605176883156213219983011392724070678633758652939051248987072469444200627"));
-    round_constants.push_back(FieldT(
-        "37024565646714391930474489137778856553925761915366252060067939966442059957164"));
-    round_constants.push_back(FieldT(
-        "7989471243134634308962365261048299254340659799910534445820512869869542788064"));
-    round_constants.push_back(FieldT(
-        "15648939481289140348738679797715724220399212972574021006219862339465296839884"));
-    round_constants.push_back(FieldT(
-        "100133438935846292803417679717817950677446943844926655798697284495340753961844"));
-    round_constants.push_back(FieldT(
-        "84618212755822467879717121296483255659772850854170590780922087915497421596465"));
-    round_constants.push_back(FieldT(
-        "66815981435852782130184794409662156021404245655267602728283138458689925010111"));
-    round_constants.push_back(FieldT(
-        "100011403138602452635630699813302791324969902443516593676764382923531277739340"));
-    round_constants.push_back(FieldT(
-        "57430361797750645341842394309545159343198597441951985629580530284393758413106"));
-    round_constants.push_back(FieldT(
-        "70240009849732555205629614425470918637568887938810907663457802670777054165279"));
-    round_constants.push_back(FieldT(
-        "115341201140672997375646566164431266507025151688875346248495663683620086806942"));
-    round_constants.push_back(FieldT(
-        "11188962021222070760150833399355814187143871338754315850627637681691407594017"));
-    round_constants.push_back(FieldT(
-        "22685520879254273934490401340849316430229408194604166253482138215686716109430"));
-    round_constants.push_back(FieldT(
-        "51189210546148312327463530170430162293845070064001770900624850430825589457055"));
-    round_constants.push_back(FieldT(
-        "14807565813027010873011142172745696288480075052292277459306275231121767039664"));
-    round_constants.push_back(FieldT(
-        "95539138374056424883213912295679274059417180869462186511207318536449091576661"));
-    round_constants.push_back(FieldT(
-        "113489397464329757187555603731541774715600099685729291423921796997078292946609"));
-    round_constants.push_back(FieldT(
-        "104312240868162447193722372229442001535106018532365202206691174960555358414880"));
-    round_constants.push_back(FieldT(
-        "8267151326618998101166373872748168146937148303027773815001564349496401227343"));
-    round_constants.push_back(FieldT(
-        "76298755107890528830128895628139521831584444593650120338808262678169950673284"));
-    round_constants.push_back(FieldT(
-        "73002305935054160156217464153178860593131914821282451210510325210791458847694"));
-    round_constants.push_back(FieldT(
-        "74544443080560119509560262720937836494902079641131221139823065933367514898276"));
-    round_constants.push_back(FieldT(
-        "36856043990250139109110674451326757800006928098085552406998173198427373834846"));
+    round_constants = {
+        FieldT("0"),
+        FieldT("22159019873790129476324495190496603411493310235845550845393361088354059025587"),
+        FieldT("27761654615899466766976328798614662221520122127418767386594587425934055859027"),
+        FieldT("94824950344308939111646914673652476426466554475739520071212351703914847519222"),
+        FieldT("84875755167904490740680810908425347913240786521935721949482414218097022905238"),
+        FieldT("103827469404022738626089808362855974444473512881791722903435218437949312500276"),
+        FieldT("79151333313630310680682684119244096199179603958178503155035988149812024220238"),
+        FieldT("69032546029442066350494866745598303896748709048209836077355812616627437932521"),
+        FieldT("71828934229806034323678289655618358926823037947843672773514515549250200395747"),
+        FieldT("20380360065304068228640594346624360147706079921816528167847416754157399404427"),
+        FieldT("33389882590456326015242966586990383840423378222877476683761799984554709177407"),
+        FieldT("50122810070778420844700285367936543284029126632619100118638682958218725318756"),
+        FieldT("49246859699528342369154520789249265070136349803358469088610922925489948122588"),
+        FieldT("42301293999667742503298132605205313473294493780037112351216393454277775233701"),
+        FieldT("84114918321547685007627041787929288135785026882582963701427252073231899729239"),
+        FieldT("62442564517333183431281494169332072638102772915973556148439397377116238052032"),
+        FieldT("90371696767943970492795296318744142024828099537644566050263944542077360454000"),
+        FieldT("115430938798103259020685569971731347341632428718094375123887258419895353452385"),
+        FieldT("113486567655643015051612432235944767094037016028918659325405959747202187788641"),
+        FieldT("42521224046978113548086179860571260859679910353297292895277062016640527060158"),
+        FieldT("59337418021535832349738836949730504849571827921681387254433920345654363097721"),
+        FieldT("11312792726948192147047500338922194498305047686482578113645836215734847502787"),
+        FieldT("5531104903388534443968883334496754098135862809700301013033503341381689618972"),
+        FieldT("67267967506593457603372921446668397713655666818276613345969561709158934132467"),
+        FieldT("14150601882795046585170507190892504128795190437985555320824531798948976631295"),
+        FieldT("85062650450907709431728516509140931676564801299509460081586249478375415684322"),
+        FieldT("3190636703526705373452173482292964566521687248139217048214149162895182633187"),
+        FieldT("94697707246459731032848302079578714910941380385884087153796554334872238022178"),
+        FieldT("105237079024348272465679804525604310926083869213267017956044692586513087552889"),
+        FieldT("107666297462370279081061498341391155289817553443536637437225808625028106164694"),
+        FieldT("50658185643016152702409617752847261961811370146977869351531768522548888496960"),
+        FieldT("40194505239242861003888376856216043830225436269588275639840138989648733836164"),
+        FieldT("18446023938001439123322925291203176968088321100216399802351969471087090508798"),
+        FieldT("56716868411561319312404565555682857409226456576794830238428782927207680423406"),
+        FieldT("99446603622401702299467002115709680008186357666919726252089514718382895122907"),
+        FieldT("14440268383603206763216449941954085575335212955165966039078057319953582173633"),
+        FieldT("19800531992512132732080265836821627955799468140051158794892004229352040429024"),
+        FieldT("105297016338495372394147178784104774655759157445835217996114870903812070518445"),
+        FieldT("25603899274511343521079846952994517772529013612481201245155078199291999403355"),
+        FieldT("42343992762533961606462320250264898254257373842674711124109812370529823212221"),
+        FieldT("10746157796797737664081586165620034657529089112211072426663365617141344936203"),
+        FieldT("83415911130754382252267592583976834889211427666721691843694426391396310581540"),
+        FieldT("90866605176883156213219983011392724070678633758652939051248987072469444200627"),
+        FieldT("37024565646714391930474489137778856553925761915366252060067939966442059957164"),
+        FieldT("7989471243134634308962365261048299254340659799910534445820512869869542788064"),
+        FieldT("15648939481289140348738679797715724220399212972574021006219862339465296839884"),
+        FieldT("100133438935846292803417679717817950677446943844926655798697284495340753961844"),
+        FieldT("84618212755822467879717121296483255659772850854170590780922087915497421596465"),
+        FieldT("66815981435852782130184794409662156021404245655267602728283138458689925010111"),
+        FieldT("100011403138602452635630699813302791324969902443516593676764382923531277739340"),
+        FieldT("57430361797750645341842394309545159343198597441951985629580530284393758413106"),
+        FieldT("70240009849732555205629614425470918637568887938810907663457802670777054165279"),
+        FieldT("115341201140672997375646566164431266507025151688875346248495663683620086806942"),
+        FieldT("11188962021222070760150833399355814187143871338754315850627637681691407594017"),
+        FieldT("22685520879254273934490401340849316430229408194604166253482138215686716109430"),
+        FieldT("51189210546148312327463530170430162293845070064001770900624850430825589457055"),
+        FieldT("14807565813027010873011142172745696288480075052292277459306275231121767039664"),
+        FieldT("95539138374056424883213912295679274059417180869462186511207318536449091576661"),
+        FieldT("113489397464329757187555603731541774715600099685729291423921796997078292946609"),
+        FieldT("104312240868162447193722372229442001535106018532365202206691174960555358414880"),
+        FieldT("8267151326618998101166373872748168146937148303027773815001564349496401227343"),
+        FieldT("76298755107890528830128895628139521831584444593650120338808262678169950673284"),
+        FieldT("73002305935054160156217464153178860593131914821282451210510325210791458847694"),
+        FieldT("74544443080560119509560262720937836494902079641131221139823065933367514898276"),
+        FieldT("36856043990250139109110674451326757800006928098085552406998173198427373834846"),
+        FieldT("89876265522016337550524744707009312276376790319197860491657618155961055194949"),
+        FieldT("110827903006446644954303964609043521818500007209339765337677716791359271709709"),
+        FieldT("19507166101303357762640682204614541813131172968402646378144792525256753001746"),
+        FieldT("107253144238416209039771223682727408821599541893659793703045486397265233272366"),
+        FieldT("50595349797145823467207046063156205987118773849740473190540000392074846997926"),
+        FieldT("44703482889665897122601827877356260454752336134846793080442136212838463818460"),
+        FieldT("72587689163044446617379334085046687704026377073069181869522598220420039333904"),
+        FieldT("102651401786920090371975453907921346781687924794638352783098945209363379010084"),
+        FieldT("93452870373806728605513560063145330258676656934938716540885043830342716774537"),
+        FieldT("78296669596559313198894751403351590225284664485458045241864014863714864424243"),
+        FieldT("115089219682233450926699488628267277641700041858332325616476033644461392438459"),
+        FieldT("12503229023709380637667243769419362848195673442247523096260626221166887267863"),
+        FieldT("4710254915107472945023322521703570589554948344762175784852248799008742965033"),
+        FieldT("7718237385336937042064321465151951780913850666971695410931421653062451982185"),
+        FieldT("115218487714637830492048339157964615618803212766527542809597433013530253995292"),
+        FieldT("30146276054995781136885926012526705051587400199196161599789168368938819073525"),
+        FieldT("81645575619063610562025782726266715757461113967190574155696199274188206173145"),
+        FieldT("103065286526250765895346723898189993161715212663393551904337911885906019058491"),
+        FieldT("19401253163389218637767300383887292725233192135251696535631823232537040754970"),
+        FieldT("39843332085422732827481601668576197174769872102167705377474553046529879993254"),
+        FieldT("27288628349107331632228897768386713717171618488175838305048363657709955104492"),
+        FieldT("63512042813079522866974560192099016266996589861590638571563519363305976473166"),
+        FieldT("88099896769123586138541398153669061847681467623298355942484821247745931328016"),
+        FieldT("69497565113721491657291572438744729276644895517335084478398926389231201598482"),
+        FieldT("17118586436782638926114048491697362406660860405685472757612739816905521144705"),
+        FieldT("50507769484714413215987736701379019852081133212073163694059431350432441698257"),
+        FieldT("58260458108608505301755075857897657610125730489308125711681594839108744994599"),
+        FieldT("74417125471829501682706919197813397955210189244710764612359440617050537569714")
+    };
     // clang-format on
 
     assert(round_constants.size() == MaxRounds);