From 17cb9593643f9f66b8ca5f56cbdae6cc6d6d2c65 Mon Sep 17 00:00:00 2001
From: Kobi Gurkan <kobigurk@gmail.com>
Date: Sun, 2 Jun 2019 00:19:07 +0300
Subject: [PATCH] Adds a sponge hash function based on MiMC2n-n

---
 circuits/mimcsponge.circom                    | 283 ++++++++++++++++++
 ...ntconstants..js => mimc_printconstants.js} |   0
 src/mimcsponge.js                             |  77 +++++
 src/mimcsponge_gencontract.js                 | 124 ++++++++
 src/mimcsponge_printconstants.js              |  13 +
 src/mimcsponge_printcontract.js               |  13 +
 test/circuits/mimc_sponge_hash_test.circom    |   3 +
 test/circuits/mimc_sponge_test.circom         |   3 +
 test/mimcspongecircuit.js                     |  58 ++++
 test/mimcspongecontract.js                    |  53 ++++
 10 files changed, 627 insertions(+)
 create mode 100644 circuits/mimcsponge.circom
 rename src/{mimc_printconstants..js => mimc_printconstants.js} (100%)
 create mode 100644 src/mimcsponge.js
 create mode 100644 src/mimcsponge_gencontract.js
 create mode 100644 src/mimcsponge_printconstants.js
 create mode 100644 src/mimcsponge_printcontract.js
 create mode 100644 test/circuits/mimc_sponge_hash_test.circom
 create mode 100644 test/circuits/mimc_sponge_test.circom
 create mode 100644 test/mimcspongecircuit.js
 create mode 100644 test/mimcspongecontract.js

diff --git a/circuits/mimcsponge.circom b/circuits/mimcsponge.circom
new file mode 100644
index 0000000..3debbb8
--- /dev/null
+++ b/circuits/mimcsponge.circom
@@ -0,0 +1,283 @@
+// implements MiMC-2n/n as hash using a sponge construction.
+// log_5(21888242871839275222246405745257275088548364400416034343698204186575808495617) ~= 110
+// => nRounds should be 220
+template MiMCSponge(nInputs, nRounds, nOutputs) {
+  signal input ins[nInputs];
+  signal input k;
+  signal output outs[nOutputs];
+
+  // S = R||C
+  component S[nInputs + nOutputs - 1];
+
+  for (var i = 0; i < nInputs; i++) {
+    S[i] = MiMCFeistel(nRounds);
+    S[i].k <== k;
+    if (i == 0) {
+      S[i].xL_in <== ins[0];
+      S[i].xR_in <== 0;
+    } else {
+      S[i].xL_in <== S[i-1].xL_out + ins[i];
+      S[i].xR_in <== S[i-1].xR_out;
+    }
+  }
+
+  outs[0] = S[nInputs - 1].xL_out;
+
+  for (var i = 0; i < nOutputs - 1; i++) {
+    S[nInputs + i] = MiMCFeistel(nRounds);
+    S[nInputs + i].k <== k;
+    S[nInputs + i].xL_in <== S[nInputs + i - 1].xL_out;
+    S[nInputs + i].xR_in <== S[nInputs + i - 1].xR_out;
+    outs[i + 1] <== S[nInputs + i].xL_out;
+  }
+}
+
+template MiMCFeistel(nrounds) {
+    signal input xL_in;
+    signal input xR_in;
+    signal input k;
+    signal output xL_out;
+    signal output xR_out;
+
+    var c = [
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+      15092262360719700162343163278648422751610766427236295023221516498310468956361,
+      21578580340755653236050830649990190843552802306886938815497471545814130084980,
+      1258781501221760320019859066036073675029057285507345332959539295621677296991,
+      3819598418157732134449049289585680301176983019643974929528867686268702720163,
+      8653175945487997845203439345797943132543211416447757110963967501177317426221,
+      6614652990340435611114076169697104582524566019034036680161902142028967568142,
+      19212515502973904821995111796203064175854996071497099383090983975618035391558,
+      18664315914479294273286016871365663486061896605232511201418576829062292269769,
+      11498264615058604317482574216318586415670903094838791165247179252175768794889,
+      10814026414212439999107945133852431304483604215416531759535467355316227331774,
+      17566185590731088197064706533119299946752127014428399631467913813769853431107,
+      14016139747289624978792446847000951708158212463304817001882956166752906714332,
+      8242601581342441750402731523736202888792436665415852106196418942315563860366,
+      9244680976345080074252591214216060854998619670381671198295645618515047080988,
+      12216779172735125538689875667307129262237123728082657485828359100719208190116,
+      10702811721859145441471328511968332847175733707711670171718794132331147396634,
+      6479667912792222539919362076122453947926362746906450079329453150607427372979,
+      15117544653571553820496948522381772148324367479772362833334593000535648316185,
+      6842203153996907264167856337497139692895299874139131328642472698663046726780,
+      12732823292801537626009139514048596316076834307941224506504666470961250728055,
+      6936272626871035740815028148058841877090860312517423346335878088297448888663,
+      17297554111853491139852678417579991271009602631577069694853813331124433680030,
+      16641596134749940573104316021365063031319260205559553673368334842484345864859,
+      7400481189785154329569470986896455371037813715804007747228648863919991399081,
+      2273205422216987330510475127669563545720586464429614439716564154166712854048,
+      15162538063742142685306302282127534305212832649282186184583465569986719234456,
+      5628039096440332922248578319648483863204530861778160259559031331287721255522,
+      16085392195894691829567913404182676871326863890140775376809129785155092531260,
+      14227467863135365427954093998621993651369686288941275436795622973781503444257,
+      18224457394066545825553407391290108485121649197258948320896164404518684305122,
+      274945154732293792784580363548970818611304339008964723447672490026510689427,
+      11050822248291117548220126630860474473945266276626263036056336623671308219529,
+      2119542016932434047340813757208803962484943912710204325088879681995922344971,
+      12785816057369026966653780180257549951796705239580629452502836335892168319323
+    ];
+
+    var t;
+    signal t2[nrounds];
+    signal t4[nrounds];
+    signal xL[nrounds-1];
+    signal xR[nrounds-1];
+
+    for (var i=0; i<nrounds; i++) {
+        t = (i==0) ? k+xL_in : k + xL[i-1] + c[i];
+        t2[i] <== t*t;
+        t4[i] <== t2[i]*t2[i];
+        if (i<nrounds-1) {
+          xL[i] <== ((i==0) ? xR_in : xR[i-1]) + t4[i]*t;
+          xR[i] = (i==0) ? xL_in : xL[i-1];
+        } else {
+          xL_out <== xR[i-1] + t4[i]*t;
+          xR_out <== xL[i-1];
+        }
+    }
+}
diff --git a/src/mimc_printconstants..js b/src/mimc_printconstants.js
similarity index 100%
rename from src/mimc_printconstants..js
rename to src/mimc_printconstants.js
diff --git a/src/mimcsponge.js b/src/mimcsponge.js
new file mode 100644
index 0000000..651cb3c
--- /dev/null
+++ b/src/mimcsponge.js
@@ -0,0 +1,77 @@
+const bn128 = require("snarkjs").bn128;
+const bigInt = require("snarkjs").bigInt;
+const Web3Utils = require("web3-utils");
+const F = bn128.Fr;
+
+const SEED = "mimcsponge";
+const NROUNDS = 220;
+
+exports.getIV = (seed) => {
+    if (typeof seed === "undefined") seed = SEED;
+    const c = Web3Utils.keccak256(seed+"_iv");
+    const cn = bigInt(Web3Utils.toBN(c).toString());
+    const iv = cn.mod(F.q);
+    return iv;
+};
+
+exports.getConstants = (seed, nRounds) => {
+    if (typeof seed === "undefined") seed = SEED;
+    if (typeof nRounds === "undefined") nRounds = NROUNDS;
+    const cts = new Array(nRounds);
+    let c = Web3Utils.keccak256(SEED);
+    for (let i=1; i<nRounds; i++) {
+        c = Web3Utils.keccak256(c);
+
+        const n1 = Web3Utils.toBN(c).mod(Web3Utils.toBN(F.q.toString()));
+        const c2 = Web3Utils.padLeft(Web3Utils.toHex(n1), 64);
+        cts[i] = bigInt(Web3Utils.toBN(c2).toString());
+    }
+    cts[0] = bigInt(0);
+    return cts;
+};
+
+const cts = exports.getConstants(SEED, 220);
+
+exports.hash = (_xL_in, _xR_in, _k) =>{
+    let xL = bigInt(_xL_in);
+    let xR = bigInt(_xR_in);
+    const k = bigInt(_k);
+    for (let i=0; i<NROUNDS; i++) {
+        const c = cts[i];
+        const t = (i==0) ? F.add(xL, k) : F.add(F.add(xL, k), c);
+        const xR_tmp = bigInt(xR);
+        xR = xL;
+        xL = F.add(xR_tmp, F.exp(t, 5));
+    }
+    return {
+      xL: F.affine(xL),
+      xR: F.affine(xR),
+    };
+};
+
+exports.multiHash = (arr, key, numOutputs) => {
+    if (typeof(numOutputs) === "undefined") {
+      numOutputs = 1;
+    }
+    let R = F.zero;
+    let C = F.zero;
+
+    for (let i=0; i<arr.length; i++) {
+      R = F.add(R, bigInt(arr[i]));
+      const S = exports.hash(R, C, key);
+      R = S.xL;
+      C = S.xR;
+    }
+    let outputs = [R];
+    for (let i=1; i < numOutputs; i++) {
+      const S = exports.hash(R, C, key);
+      R = S.xL;
+      C = S.xR;
+      outputs.push(R);
+    }
+    if (numOutputs == 1) {
+      return F.affine(outputs[0]);
+    } else {
+      return outputs.map(x => F.affine(x));
+    }
+};
diff --git a/src/mimcsponge_gencontract.js b/src/mimcsponge_gencontract.js
new file mode 100644
index 0000000..e9bac2c
--- /dev/null
+++ b/src/mimcsponge_gencontract.js
@@ -0,0 +1,124 @@
+// Copyright (c) 2018 Jordi Baylina
+// License: LGPL-3.0+
+//
+
+const Web3Utils = require("web3-utils");
+
+const Contract = require("./evmasm");
+
+function createCode(seed, n) {
+
+    let ci = Web3Utils.keccak256(seed);
+
+    const C = new Contract();
+
+    C.push(0x64);
+    C.push("0x00");
+    C.push("0x00");
+    C.calldatacopy();
+    C.push("0x0100000000000000000000000000000000000000000000000000000000");
+    C.push("0x00");
+    C.mload();
+    C.div();
+    C.push("0x3f1a1187"); // MiMCSponge(uint256,uint256,uint256)
+    C.eq();
+    C.jmpi("start");
+    C.invalid();
+
+    C.label("start");
+    C.push("0x30644e72e131a029b85045b68181585d2833e84879b9709143e1f593f0000001");  // q
+    C.push("0x44");
+    C.mload();          // k q
+    C.push("0x04");
+    C.mload();          // xL k q
+    C.dup(2);           // q xL k q
+    C.push("0x24");
+    C.mload();          // xR q xL k q
+    C.dup(1);           // q xR q xL k q
+    C.dup(0);           // q q xR q xL k q
+    C.dup(4);           // xL q q xR q xL k q
+    C.dup(6);           // k xL q q xR q xL k q
+    C.addmod();         // t=k+xL q xR q xL k q
+    C.dup(1);           // q t q xR q xL k q
+    C.dup(0);           // q q t q xR q xL k q
+    C.dup(2);           // t q q t q xR q xL k q
+    C.dup(0);           // t t q q t q xR q xL k q
+    C.mulmod();         // b=t^2 q t q xR q xL k q
+    C.dup(0);           // b b q t q xR q xL k q
+    C.mulmod();         // c=t^4 t q xR q xL k q
+    C.mulmod();         // d=t^5 xR q xL k q
+    C.addmod();         // e=t^5+xR xL k q (for next round: xL xR k q)
+
+    for (let i=0; i<n-1; i++) {
+        ci = Web3Utils.keccak256(ci);
+        C.swap(1);      // xR xL k q
+        C.dup(3);       // q xR xL k q
+        C.dup(3);       // k q xR xL k q
+        C.dup(1);       // q k q xR xL k q
+        C.dup(4);       // xL q k q xR xL k q
+        C.push(ci);     // ci xL q k q xR xL k q
+        C.addmod();     // a=ci+xL k q xR xL k q
+        C.addmod();     // t=a+k xR xL k q
+        C.dup(4);       // q t xR xL k q
+        C.swap(1);      // t q xR xL k q
+        C.dup(1);       // q t q xR xL k q
+        C.dup(0);       // q q t q xR xL k q
+        C.dup(2);       // t q q t q xR xL k q
+        C.dup(0);       // t t q q t q xR xL k q
+        C.mulmod();     // b=t^2 q t q xR xL k q
+        C.dup(0);       // b b q t q xR xL k q
+        C.mulmod();     // c=t^4 t q xR xL k q
+        C.mulmod();     // d=t^5 xR xL k q
+        C.dup(4);       // q d xR xL k q
+        C.swap(2);      // xR d q xL k q
+        C.addmod();     // e=t^5+xR xL k q (for next round: xL xR k q)
+    }
+
+    C.push("0x00");
+    C.mstore();     // Save it to pos 0;
+    C.push("0x20");
+    C.mstore();     // Save it to pos 1;
+    C.push("0x40");
+    C.push("0x00");
+    C.return();
+
+    return C.createTxData();
+}
+
+module.exports.abi = [
+    {
+        "constant": true,
+        "inputs": [
+            {
+                "name": "xL_in",
+                "type": "uint256"
+            },
+            {
+                "name": "xR_in",
+                "type": "uint256"
+            },
+            {
+                "name": "k",
+                "type": "uint256"
+            }
+        ],
+        "name": "MiMCSponge",
+        "outputs": [
+            {
+                "name": "xL",
+                "type": "uint256"
+            },
+            {
+                "name": "xR",
+                "type": "uint256"
+            }
+        ],
+        "payable": false,
+        "stateMutability": "pure",
+        "type": "function"
+    }
+];
+
+module.exports.createCode = createCode;
+
+
diff --git a/src/mimcsponge_printconstants.js b/src/mimcsponge_printconstants.js
new file mode 100644
index 0000000..4f8292e
--- /dev/null
+++ b/src/mimcsponge_printconstants.js
@@ -0,0 +1,13 @@
+const mimcsponge = require("./mimcsponge.js");
+
+const nRounds = 220;
+let S = "[\n";
+const cts = mimcsponge.getConstants();
+for (let i=0; i<nRounds; i++) {
+    S = S + cts[i].toString();
+    if (i<nRounds-1) S = S + ",";
+    S=S+"\n";
+}
+S = S + "]\n";
+
+console.log(S);
diff --git a/src/mimcsponge_printcontract.js b/src/mimcsponge_printcontract.js
new file mode 100644
index 0000000..d9ec862
--- /dev/null
+++ b/src/mimcsponge_printcontract.js
@@ -0,0 +1,13 @@
+const mimcGenContract = require("./mimcsponge_gencontract");
+
+const SEED = "mimcsponge";
+
+let nRounds;
+if (typeof process.argv[2] != "undefined") {
+    nRounds = parseInt(process.argv[2]);
+} else {
+    nRounds = 220;
+}
+
+console.log(mimcGenContract.createCode(SEED, nRounds));
+
diff --git a/test/circuits/mimc_sponge_hash_test.circom b/test/circuits/mimc_sponge_hash_test.circom
new file mode 100644
index 0000000..f6be502
--- /dev/null
+++ b/test/circuits/mimc_sponge_hash_test.circom
@@ -0,0 +1,3 @@
+include "../../circuits/mimcsponge.circom"
+
+component main = MiMCSponge(2, 220, 3);
diff --git a/test/circuits/mimc_sponge_test.circom b/test/circuits/mimc_sponge_test.circom
new file mode 100644
index 0000000..92e9df2
--- /dev/null
+++ b/test/circuits/mimc_sponge_test.circom
@@ -0,0 +1,3 @@
+include "../../circuits/mimcsponge.circom"
+
+component main = MiMCFeistel(220);
diff --git a/test/mimcspongecircuit.js b/test/mimcspongecircuit.js
new file mode 100644
index 0000000..b114924
--- /dev/null
+++ b/test/mimcspongecircuit.js
@@ -0,0 +1,58 @@
+const chai = require("chai");
+const path = require("path");
+const snarkjs = require("snarkjs");
+const compiler = require("circom");
+
+const mimcjs = require("../src/mimcsponge.js");
+
+const assert = chai.assert;
+
+describe("MiMC Sponge Circuit test", function () {
+    let circuit;
+
+    this.timeout(100000);
+
+    it("Should check permutation", async () => {
+        const cirDef = await compiler(path.join(__dirname, "circuits", "mimc_sponge_test.circom"));
+
+        circuit = new snarkjs.Circuit(cirDef);
+
+        console.log("MiMC Feistel constraints: " + circuit.nConstraints);
+
+        const w = circuit.calculateWitness({xL_in: 1, xR_in: 2, k: 3});
+
+        const xLout = w[circuit.getSignalIdx("main.xL_out")];
+        const xRout = w[circuit.getSignalIdx("main.xR_out")];
+
+        const out2 = mimcjs.hash(1,2,3);
+
+        assert.equal(xLout.toString(), out2.xL.toString());
+        assert.equal(xRout.toString(), out2.xR.toString());
+
+        assert(circuit.checkWitness(w));
+
+    });
+
+    it("Should check hash", async () => {
+        const cirDef = await compiler(path.join(__dirname, "circuits", "mimc_sponge_hash_test.circom"));
+
+        circuit = new snarkjs.Circuit(cirDef);
+
+        console.log("MiMC Sponge constraints: " + circuit.nConstraints);
+
+        const w = circuit.calculateWitness({ins: [1, 2], k: 0});
+
+        const o1 = w[circuit.getSignalIdx("main.outs[0]")];
+        const o2 = w[circuit.getSignalIdx("main.outs[1]")];
+        const o3 = w[circuit.getSignalIdx("main.outs[2]")];
+
+        const out2 = mimcjs.multiHash([1,2], 0, 3);
+
+        assert.equal(o1.toString(), out2[0].toString());
+        assert.equal(o2.toString(), out2[1].toString());
+        assert.equal(o3.toString(), out2[2].toString());
+
+        assert(circuit.checkWitness(w));
+
+    });
+});
diff --git a/test/mimcspongecontract.js b/test/mimcspongecontract.js
new file mode 100644
index 0000000..1f50a50
--- /dev/null
+++ b/test/mimcspongecontract.js
@@ -0,0 +1,53 @@
+const TestRPC = require("ganache-cli");
+const Web3 = require("web3");
+const chai = require("chai");
+const mimcGenContract = require("../src/mimcsponge_gencontract.js");
+const mimcjs = require("../src/mimcsponge.js");
+
+
+const assert = chai.assert;
+const log = (msg) => { if (process.env.MOCHA_VERBOSE) console.log(msg); };
+
+const SEED = "mimcsponge";
+
+describe("MiMC Sponge Smart contract test", () => {
+    let testrpc;
+    let web3;
+    let mimc;
+    let accounts;
+
+    before(async () => {
+        testrpc = TestRPC.server({
+            ws: true,
+            gasLimit: 5800000,
+            total_accounts: 10,
+        });
+
+        testrpc.listen(8546, "127.0.0.1");
+
+        web3 = new Web3("ws://127.0.0.1:8546");
+        accounts = await web3.eth.getAccounts();
+    });
+
+    after(async () => testrpc.close());
+
+    it("Should deploy the contract", async () => {
+        const C = new web3.eth.Contract(mimcGenContract.abi);
+
+        mimc = await C.deploy({
+            data: mimcGenContract.createCode(SEED, 220)
+        }).send({
+            gas: 3500000,
+            from: accounts[0]
+        });
+    });
+
+    it("Shold calculate the mimc correctly", async () => {
+        const res = await mimc.methods.MiMCSponge(1,2,3).call();
+        const res2 = await mimcjs.hash(1,2,3);
+
+        assert.equal(res.xL.toString(), res2.xL.toString());
+        assert.equal(res.xR.toString(), res2.xR.toString());
+    });
+});
+