diff --git a/circuits/poseidon.circom b/circuits/poseidon.circom
index 70635ddb..fd6c4939 100644
--- a/circuits/poseidon.circom
+++ b/circuits/poseidon.circom
@@ -30,7 +30,7 @@ template Mix(t, M) {
     for (var i=0; i<t; i++) {
         lc = 0;
         for (var j=0; j<t; j++) {
-            lc += M[j][i]*in[j];
+            lc += M[i][j]*in[j];
         }
         out[i] <== lc;
     }
@@ -50,19 +50,19 @@ template Poseidon(nInputs) {
     var C[t*(nRoundsF + nRoundsP)] = POSEIDON_C(t);
     var M[t][t] = POSEIDON_M(t);
 
-    component ark[nRoundsF + nRoundsP - 1];
-    component sigmaF[nRoundsF - 1][t];
+    component ark[nRoundsF + nRoundsP];
+    component sigmaF[nRoundsF][t];
     component sigmaP[nRoundsP];
-    component mix[nRoundsF + nRoundsP - 1];
+    component mix[nRoundsF + nRoundsP];
 
     var k;
 
-    for (var i=0; i<nRoundsF + nRoundsP - 1; i++) {
+    for (var i=0; i<nRoundsF + nRoundsP; i++) {
         ark[i] = Ark(t, C, t*i);
         for (var j=0; j<t; j++) {
             if (i==0) {
-                if (j<nInputs) {
-                    ark[i].in[j] <== inputs[j];
+                if (j>0) {
+                    ark[i].in[j] <== inputs[j-1];
                 } else {
                     ark[i].in[j] <== 0;
                 }
@@ -91,8 +91,5 @@ template Poseidon(nInputs) {
         }
     }
 
-    // last round is done only for the first word, so we do it manually to save constraints
-    component lastSigmaF = Sigma();
-    lastSigmaF.in <== mix[nRoundsF + nRoundsP - 2].out[0] + C[t*(nRoundsF + nRoundsP - 1)];
-    out <== lastSigmaF.out;
+    out <== mix[nRoundsF + nRoundsP -1].out[0];
 }
diff --git a/src/poseidon.js b/src/poseidon.js
index bcd54475..af63c409 100644
--- a/src/poseidon.js
+++ b/src/poseidon.js
@@ -26,7 +26,7 @@ function poseidon(inputs) {
     const nRoundsF = N_ROUNDS_F;
     const nRoundsP = N_ROUNDS_P[t - 2];
 
-    let state = [...inputs.map(a => F.e(a)), F.zero];
+    let state = [F.zero, ...inputs.map(a => F.e(a))];
     for (let r = 0; r < nRoundsF + nRoundsP; r++) {
         state = state.map((a, i) => F.add(a, C[t - 2][r * t + i]));
 
@@ -36,12 +36,9 @@ function poseidon(inputs) {
             state[0] = pow5(state[0]);
         }
 
-        // no matrix multiplication in the last round
-        if (r < nRoundsF + nRoundsP - 1) {
-            state = state.map((_, i) =>
-                state.reduce((acc, a, j) => F.add(acc, F.mul(M[t - 2][j][i], a)), F.zero)
-            );
-        }
+        state = state.map((_, i) =>
+            state.reduce((acc, a, j) => F.add(acc, F.mul(M[t - 2][i][j], a)), F.zero)
+        );
     }
     return F.normalize(state[0]);
 }
diff --git a/src/poseidon_gencontract.js b/src/poseidon_gencontract.js
index 3f896abf..1ca16a53 100644
--- a/src/poseidon_gencontract.js
+++ b/src/poseidon_gencontract.js
@@ -29,7 +29,7 @@ function createCode(nInputs) {
     function saveM() {
         for (let i=0; i<t; i++) {
             for (let j=0; j<t; j++) {
-                C.push(toHex256(M[t-2][j][i]));
+                C.push(toHex256(M[t-2][i][j]));
                 C.push((1+i*t+j)*32);
                 C.mstore();
             }
@@ -120,12 +120,14 @@ function createCode(nInputs) {
     // The function has a single array param param
     // [Selector (4)] [item1 (32)] [item2 (32)] ....
     // Stack positions 0-nInputs.
-    for (let i=0; i<t; i++) {
-        C.push(0x04+(0x20*(nInputs-i)));
+    for (let i=0; i<nInputs; i++) {
+        C.push(0x04+(0x20*(nInputs-i-1)));
         C.calldataload();
     }
 
-    for (let i=0; i<nRoundsF+nRoundsP-1; i++) {
+    C.push(0);
+
+    for (let i=0; i<nRoundsF+nRoundsP; i++) {
         ark(i);
         if ((i<nRoundsF/2) || (i>=nRoundsP+nRoundsF/2)) {
             for (let j=0; j<t; j++) {
@@ -142,13 +144,6 @@ function createCode(nInputs) {
         C.label(strLabel);
     }
 
-    C.push(toHex256(K[t-2][(nRoundsF+nRoundsP-1)*t]));  // K, st, q
-    C.dup(t+1); // q, K, st, q
-    C.swap(2);  // st[0], K, q, st\st[0]
-    C.addmod();  // st q
-
-    sigma(0);
-
     C.push("0x00");
     C.mstore();     // Save it to pos 0;
     C.push("0x20");
diff --git a/test/eddsa_js.js b/test/eddsa_js.js
index dbe8e462..8e731152 100644
--- a/test/eddsa_js.js
+++ b/test/eddsa_js.js
@@ -67,12 +67,12 @@ describe("EdDSA js test", function () {
         assert.equal(signature.R8[1].toString(),
             "15383486972088797283337779941324724402501462225528836549661220478783371668959");
         assert.equal(signature.S.toString(),
-            "1398758333392199195742243841591064350253744445503462896781493968760929513778");
+            "1672775540645840396591609181675628451599263765380031905495115170613215233181");
 
         const pSignature = eddsa.packSignature(signature);
         assert.equal(pSignature.toString("hex"), ""+
             "dfedb4315d3f2eb4de2d3c510d7a987dcab67089c8ace06308827bf5bcbe02a2"+
-            "32f16b0f2f4c4e1169aa59685637e1429b6581a9531d058d65f4ab224eab1703");
+            "9d043ece562a8f82bfc0adb640c0107a7d3a27c1c7c1a6179a0da73de5c1b203");
 
         const uSignature = eddsa.unpackSignature(pSignature);
         assert(eddsa.verifyPoseidon(msg, uSignature, pubKey));
diff --git a/test/poseidoncircuit.js b/test/poseidoncircuit.js
index 4b61f064..ede13b1b 100644
--- a/test/poseidoncircuit.js
+++ b/test/poseidoncircuit.js
@@ -21,7 +21,8 @@ describe("Poseidon Circuit test", function () {
         const w = await circuit6.calculateWitness({inputs: [1, 2, 0,0,0]}, true);
 
         const res2 = poseidon([1,2,0,0,0]);
-        assert.equal("3975478831357328722254985704342968745327876719981393787143845259590563829094", res2.toString());
+
+        assert.equal("1018317224307729531995786483840663576608797660851238720571059489595066344487", res2.toString());
         await circuit6.assertOut(w, {out : res2});
         await circuit6.checkConstraints(w);
     });
@@ -31,7 +32,7 @@ describe("Poseidon Circuit test", function () {
 
         const res2 = poseidon([3, 4,5,10,23]);
 
-        assert.equal("18540626624821144952552691894137986276337186174352554475896834101336254024067", res2.toString());
+        assert.equal("13034429309846638789535561449942021891039729847501137143363028890275222221409", res2.toString());
         await circuit6.assertOut(w, {out : res2});
         await circuit6.checkConstraints(w);
     });
@@ -41,7 +42,8 @@ describe("Poseidon Circuit test", function () {
         const w = await circuit3.calculateWitness({inputs: [1, 2]});
 
         const res2 = poseidon([1,2]);
-        assert.equal("17117985411748610629288516079940078114952304104811071254131751175361957805920", res2.toString());
+
+        assert.equal("7853200120776062878684798364095072458815029376092732009249414926327459813530", res2.toString());
         await circuit3.assertOut(w, {out : res2});
         await circuit3.checkConstraints(w);
     });
@@ -50,7 +52,8 @@ describe("Poseidon Circuit test", function () {
         const w = await circuit3.calculateWitness({inputs: [3, 4]});
 
         const res2 = poseidon([3, 4]);
-        assert.equal("21867347236198497199818917118739170715216974132230970409806500217655788551452", res2.toString());
+
+        assert.equal("14763215145315200506921711489642608356394854266165572616578112107564877678998", res2.toString());
         await circuit3.assertOut(w, {out : res2});
         await circuit3.checkConstraints(w);
     });
diff --git a/test/poseidonjs.js b/test/poseidonjs.js
new file mode 100644
index 00000000..96e5e65c
--- /dev/null
+++ b/test/poseidonjs.js
@@ -0,0 +1,15 @@
+const chai = require("chai");
+const assert = chai.assert;
+
+const poseidon = require("../src/poseidon.js");
+
+describe("Poseidon Circuit test", function () {
+    it("Should check constrain reference implementation poseidonperm_x5_254_3", async () => {
+        const res2 = poseidon([1,2]);
+        assert.equal("115cc0f5e7d690413df64c6b9662e9cf2a3617f2743245519e19607a4417189a", res2.toString(16));
+    });
+    it("Should check constrain reference implementation poseidonperm_x5_254_5", async () => {
+        const res2 = poseidon([1,2,3,4]);
+        assert.equal("299c867db6c1fdd79dcefa40e4510b9837e60ebb1ce0663dbaa525df65250465", res2.toString(16));
+    });
+});