Update to last circomlib version

On a Intel(R) Core(TM) i7-8705G CPU @ 3.10GHz, with 32 GB of RAM:

- Before ff:
hash    time:   [927.61 us 927.78 us 927.98 us]

- Previous commit:
hash    time:   [26.495 us 26.503 us 26.512 us]

- New:
hash    time:   [9.8622 us 9.9953 us 10.127 us]

Cargo.toml

@@ -11,6 +11,9 @@ readme = "README.md"
 [dependencies]
 ff = {package="ff_ce" , version="0.11", features = ["derive"]}
 rand = "0.4"
+num = "0.2.0"
+num-bigint = "0.2.2"
+tiny-keccak = "1.5"
 
 [dev-dependencies]
 criterion = "0.3"

benches/bench_mimc_hash.rs

@@ -15,12 +15,9 @@ fn criterion_benchmark(c: &mut Criterion) {
         "12242166908188651009877250812424843524687801523336557272219921456462821518061",
     )
     .unwrap();
-    let mut big_arr: Vec<Fr> = Vec::new();
-    big_arr.push(b1.clone());
-    big_arr.push(b2.clone());
-    let mimc7 = Mimc7::new();
+    let mimc7 = Mimc7::new(91);
 
-    c.bench_function("hash", |b| b.iter(|| mimc7.hash(big_arr.clone())));
+    c.bench_function("hash", |b| b.iter(|| mimc7.hash(&b1, &b2)));
 }
 
 criterion_group!(benches, criterion_benchmark);

gen_constants/.gitignore

@@ -1,3 +0,0 @@
-/target
-**/*.rs.bk
-Cargo.lock

gen_constants/Cargo.toml

@@ -1,14 +0,0 @@
-[package]
-name = "gen_constants"
-version = "0.1.0"
-authors = ["arnaucube <root@arnaucube.com>"]
-edition = "2018"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-num = "0.2.0"
-num-bigint = "0.2.2"
-num-traits = "0.2.8"
-tiny-keccak = "1.5"
-rustc-hex = "1.0.0"

gen_constants/src/main.rs

@@ -1,122 +0,0 @@
-extern crate num;
-extern crate num_bigint;
-extern crate num_traits;
-
-use tiny_keccak::Keccak;
-
-use num_bigint::{BigInt, Sign};
-use num_traits::Zero;
-
-const SEED: &str = "mimc";
-
-pub struct Constants {
-    // seed_hash: BigInt,
-    // iv: BigInt,
-    r: BigInt,
-    n_rounds: i64,
-    cts: Vec<BigInt>,
-}
-
-pub fn modulus(a: &BigInt, m: &BigInt) -> BigInt {
-    ((a % m) + m) % m
-}
-
-pub fn generate_constants() -> Constants {
-    let r: BigInt = BigInt::parse_bytes(
-        b"21888242871839275222246405745257275088548364400416034343698204186575808495617",
-        10,
-    )
-    .unwrap();
-
-    let mut keccak = Keccak::new_keccak256();
-    let mut h = [0u8; 32];
-    keccak.update(SEED.as_bytes());
-    keccak.finalize(&mut h);
-    let mut keccak = Keccak::new_keccak256();
-    let mut h_iv = [0u8; 32];
-    let seed_iv = format!("{}{}", SEED, "_iv");
-    keccak.update(seed_iv.as_bytes());
-    keccak.finalize(&mut h_iv);
-
-    // let seed_hash: BigInt = BigInt::from_bytes_be(Sign::Plus, &h);
-    // let c: BigInt = BigInt::from_bytes_be(Sign::Plus, &h_iv);
-    // let iv: BigInt = c % &r;
-    let n_rounds: i64 = 91;
-    let cts = get_constants(&r, SEED, n_rounds);
-
-    Constants {
-        // seed_hash: seed_hash,
-        // iv: iv,
-        r: r,
-        n_rounds: n_rounds,
-        cts: cts,
-    }
-}
-
-pub fn get_constants(r: &BigInt, seed: &str, n_rounds: i64) -> Vec<BigInt> {
-    let mut cts: Vec<BigInt> = Vec::new();
-    cts.push(Zero::zero());
-
-    let mut keccak = Keccak::new_keccak256();
-    let mut h = [0u8; 32];
-    keccak.update(seed.as_bytes());
-    keccak.finalize(&mut h);
-
-    let mut c = BigInt::from_bytes_be(Sign::Plus, &h);
-    for _ in 1..n_rounds {
-        let (_, c_bytes) = c.to_bytes_be();
-        let mut c_bytes32: [u8; 32] = [0; 32];
-        let diff = c_bytes32.len() - c_bytes.len();
-        c_bytes32[diff..].copy_from_slice(&c_bytes[..]);
-
-        let mut keccak = Keccak::new_keccak256();
-        let mut h = [0u8; 32];
-        keccak.update(&c_bytes[..]);
-        keccak.finalize(&mut h);
-        c = BigInt::from_bytes_be(Sign::Plus, &h);
-
-        let n = modulus(&c, &r);
-        cts.push(n);
-    }
-    // let l = cts.len();
-    // cts[l-1] = Zero::zero();
-    cts
-}
-
-fn main() {
-    let c = generate_constants();
-    println!("let cts_str: Vec<&str> = vec![");
-    for i in 0..c.cts.len() {
-        println!("  {:?},", c.cts[i].to_string());
-    }
-    println!("];");
-    println!("let n_rounds: i64 = {:?};", c.n_rounds);
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use rustc_hex::ToHex;
-
-    #[test]
-    fn test_sha3() {
-        let mut keccak = Keccak::new_keccak256();
-        let mut res = [0u8; 32];
-        keccak.update(SEED.as_bytes());
-        keccak.finalize(&mut res);
-        assert_eq!(
-            res.to_hex(),
-            "b6e489e6b37224a50bebfddbe7d89fa8fdcaa84304a70bd13f79b5d9f7951e9e"
-        );
-
-        let mut keccak = Keccak::new_keccak256();
-        let mut res = [0u8; 32];
-        keccak.update(SEED.as_bytes());
-        keccak.finalize(&mut res);
-        let c = BigInt::from_bytes_be(Sign::Plus, &res);
-        assert_eq!(
-            c.to_string(),
-            "82724731331859054037315113496710413141112897654334566532528783843265082629790"
-        );
-    }
-}

src/lib.rs

@@ -8,142 +8,79 @@ use ff::*;
 #[PrimeFieldGenerator = "7"]
 pub struct Fr(FrRepr);
 
+extern crate num;
+extern crate num_bigint;
+use num_bigint::{BigInt, Sign};
+use tiny_keccak::Keccak;
+
+const SEED: &str = "mimc";
+
 pub struct Constants {
-    n_rounds: i64,
+    n_rounds: usize,
     cts: Vec<Fr>,
 }
 
-pub fn load_constants() -> Constants {
-    // constants generated from the 'gen_constants' subpackage
-    let cts_str: Vec<&str> = vec![
-        "0",
-        "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",
-    ];
-    let n_rounds: i64 = 91;
+pub fn generate_constants(n_rounds: usize) -> Constants {
+    let cts = get_constants(SEED, n_rounds);
 
-    let mut cts: Vec<Fr> = Vec::new();
-    for i in 0..cts_str.len() {
-        let n: Fr = Fr::from_str(cts_str[i]).unwrap();
-        cts.push(n);
-    }
     Constants {
         n_rounds: n_rounds,
         cts: cts,
     }
 }
 
+pub fn get_constants(seed: &str, n_rounds: usize) -> Vec<Fr> {
+    let mut cts: Vec<Fr> = Vec::new();
+    cts.push(Fr::zero());
+
+    let mut keccak = Keccak::new_keccak256();
+    let mut h = [0u8; 32];
+    keccak.update(seed.as_bytes());
+    keccak.finalize(&mut h);
+
+    let r: BigInt = BigInt::parse_bytes(
+        b"21888242871839275222246405745257275088548364400416034343698204186575808495617",
+        10,
+    )
+    .unwrap();
+
+    let mut c = BigInt::from_bytes_be(Sign::Plus, &h);
+    for _ in 1..n_rounds {
+        let (_, c_bytes) = c.to_bytes_be();
+        let mut c_bytes32: [u8; 32] = [0; 32];
+        let diff = c_bytes32.len() - c_bytes.len();
+        c_bytes32[diff..].copy_from_slice(&c_bytes[..]);
+
+        let mut keccak = Keccak::new_keccak256();
+        let mut h = [0u8; 32];
+        keccak.update(&c_bytes[..]);
+        keccak.finalize(&mut h);
+        c = BigInt::from_bytes_be(Sign::Plus, &h);
+
+        let n = modulus(&c, &r);
+        cts.push(Fr::from_str(&n.to_string()).unwrap());
+    }
+    cts
+}
+
+pub fn modulus(a: &BigInt, m: &BigInt) -> BigInt {
+    ((a % m) + m) % m
+}
+
 pub struct Mimc7 {
     constants: Constants,
 }
 
 impl Mimc7 {
-    pub fn new() -> Mimc7 {
+    pub fn new(n_rounds: usize) -> Mimc7 {
         Mimc7 {
-            constants: load_constants(),
-        }
-    }
-
-    pub fn hash(&self, arr: Vec<Fr>) -> Fr {
-        let mut h: Fr = Fr::zero();
-        for i in 0..arr.len() {
-            h.add_assign(&self.mimc7_hash(&arr[i], &h));
-            h.add_assign(&arr[i].clone());
+            constants: generate_constants(n_rounds),
         }
-        h
     }
 
-    pub fn mimc7_hash(&self, x_in: &Fr, k: &Fr) -> Fr {
+    pub fn hash(&self, x_in: &Fr, k: &Fr) -> Fr {
         let mut h: Fr = Fr::zero();
-        for i in 0..self.constants.n_rounds as usize {
+        for i in 0..self.constants.n_rounds {
             let mut t: Fr;
             if i == 0 {
                 t = x_in.clone();
@@ -164,6 +101,16 @@ impl Mimc7 {
         h.add_assign(&k);
         h
     }
+
+    pub fn multi_hash(&self, arr: Vec<Fr>, key: &Fr) -> Fr {
+        let mut r = key.clone();
+        for i in 0..arr.len() {
+            let h = self.hash(&arr[i], &r);
+            r.add_assign(&arr[i]);
+            r.add_assign(&h);
+        }
+        r
+    }
 }
 
 #[cfg(test)]
@@ -171,8 +118,8 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_load_constants() {
-        let constants = load_constants();
+    fn test_generate_constants() {
+        let constants = generate_constants(91);
         assert_eq!(
             "Fr(0x2e2ebbb178296b63d88ec198f0976ad98bc1d4eb0d921ddd2eb86cb7e70a98e5)",
             constants.cts[1].to_string()
@@ -180,7 +127,27 @@ mod tests {
     }
 
     #[test]
-    fn test_mimc7() {
+    fn test_mimc() {
+        let b1: Fr = Fr::from_str("1").unwrap();
+        let b2: Fr = Fr::from_str("2").unwrap();
+        let mimc7 = Mimc7::new(91);
+        let h1 = mimc7.hash(&b1, &b2);
+        assert_eq!(
+            h1.to_string(),
+            "Fr(0x176c6eefc3fdf8d6136002d8e6f7a885bbd1c4e3957b93ddc1ec3ae7859f1a08)"
+        );
+
+        let b3: Fr = Fr::from_str("3").unwrap();
+        let mut arr: Vec<Fr> = Vec::new();
+        arr.push(b1.clone());
+        arr.push(b2.clone());
+        arr.push(b3.clone());
+        let h1 = mimc7.multi_hash(arr, &Fr::zero());
+        assert_eq!(
+            h1.to_string(),
+            "Fr(0x25f5a6429a9764564be3955e6f56b0b9143c571528fd30a80ae6c27dc8b4a40c)"
+        );
+
         let b12: Fr = Fr::from_str("12").unwrap();
         let b45: Fr = Fr::from_str("45").unwrap();
         let b78: Fr = Fr::from_str("78").unwrap();
@@ -188,32 +155,32 @@ mod tests {
 
         let mut big_arr1: Vec<Fr> = Vec::new();
         big_arr1.push(b12.clone());
-        let mimc7 = Mimc7::new();
-        let h1 = mimc7.hash(big_arr1);
+        let mimc7 = Mimc7::new(91);
+        let h1 = mimc7.multi_hash(big_arr1, &Fr::zero());
         assert_eq!(
             h1.to_string(),
             "Fr(0x237c92644dbddb86d8a259e0e923aaab65a93f1ec5758b8799988894ac0958fd)"
         );
 
-        let mh2 = mimc7.mimc7_hash(&b12, &b45);
+        let mh2 = mimc7.hash(&b12, &b45);
         assert_eq!(
             mh2.to_string(),
             "Fr(0x2ba7ebad3c6b6f5a20bdecba2333c63173ca1a5f2f49d958081d9fa7179c44e4)"
         );
 
-        let mut big_arr2: Vec<Fr> = Vec::new();
-        big_arr2.push(b78.clone());
-        big_arr2.push(b41.clone());
-        let h2 = mimc7.hash(big_arr2);
+        let mut big_arr1: Vec<Fr> = Vec::new();
+        big_arr1.push(b78.clone());
+        big_arr1.push(b41.clone());
+        let h2 = mimc7.multi_hash(big_arr1, &Fr::zero());
         assert_eq!(
             h2.to_string(),
             "Fr(0x067f3202335ea256ae6e6aadcd2d5f7f4b06a00b2d1e0de903980d5ab552dc70)"
         );
 
-        let mut big_arr2: Vec<Fr> = Vec::new();
-        big_arr2.push(b12.clone());
-        big_arr2.push(b45.clone());
-        let h1 = mimc7.hash(big_arr2);
+        let mut big_arr1: Vec<Fr> = Vec::new();
+        big_arr1.push(b12.clone());
+        big_arr1.push(b45.clone());
+        let h1 = mimc7.multi_hash(big_arr1, &Fr::zero());
         assert_eq!(
             h1.to_string(),
             "Fr(0x15ff7fe9793346a17c3150804bcb36d161c8662b110c50f55ccb7113948d8879)"
@@ -224,8 +191,8 @@ mod tests {
         big_arr1.push(b45.clone());
         big_arr1.push(b78.clone());
         big_arr1.push(b41.clone());
-        let mimc7 = Mimc7::new();
-        let h1 = mimc7.hash(big_arr1);
+        let mimc7 = Mimc7::new(91);
+        let h1 = mimc7.multi_hash(big_arr1, &Fr::zero());
         assert_eq!(
             h1.to_string(),
             "Fr(0x284bc1f34f335933a23a433b6ff3ee179d682cd5e5e2fcdd2d964afa85104beb)"
@@ -238,8 +205,8 @@ mod tests {
 
         let mut big_arr1: Vec<Fr> = Vec::new();
         big_arr1.push(r_1.clone());
-        let mimc7 = Mimc7::new();
-        let h1 = mimc7.hash(big_arr1);
+        let mimc7 = Mimc7::new(91);
+        let h1 = mimc7.multi_hash(big_arr1, &Fr::zero());
         assert_eq!(
             h1.to_string(),
             "Fr(0x0a4fffe99225f9972ec39fd780dd084f349286c723d4dd42ad05e2e7421fef0e)"