diff --git a/README.md b/README.md
index a8362f8..f5ea805 100644
--- a/README.md
+++ b/README.md
@@ -23,3 +23,35 @@ npm run test-sc
 ./compile-circuits.sh
 ```
 
+
+## Spec draft
+
+### Deposit
+- user generates a random `secret` & `nullifier`
+- computes the `commitment`, which is the Poseidon hash: `commitment = H(coinCode, amount, secret, nullifier)`, where:
+	- `coinCode`: code that specifies which currency is being used (`0`==ETH)
+	- `amount`: the amount to be deposited
+	- `secret`: random, private
+	- `nullifier`: random
+- get all the commitments from the SmartContract
+- build the MerkleTree with the getted commitments
+- add the new computed `commitment` into the MerkleTree
+- generate zkSNARK proof, where is proving:
+	- prover knows the `secret` & `nullifier` for the `commitment`
+	- the transition from `RootOld` (the current one in the Smart Contract) to `RootNew` has been done following the rules (only one addition, no deletion)
+- user sends ETH to the smart contract `deposit` call, together with the zkProof data
+
+Deposit circuit can be found [here](https://github.com/miksi-labs/miksi-core/blob/master/circuits/deposit.circom).
+
+### Withdraw
+- user gets all the commitments from the SmartContract
+- build the MerkleTree with the getted commitments
+- generate the siblings for the `commitment` of which the user knows the `secret` & `nullifier`
+- generate zkSNARK proof, where is proving:
+        - user knows a `secret` for a public `nullifier`
+        - which `commitment` is in the MerkleTree
+        - which MerkleTree `root` is the one that knows the SmartContract
+- if the zkProof verification passes, and the nullifier was not already used, the Smart Contract sends the ETH to the specified address
+
+Withdraw circuit can be found [here](https://github.com/miksi-labs/miksi-core/blob/master/circuits/withdraw.circom).
+
diff --git a/test/contracts/miksi.test.ts b/test/contracts/miksi.test.ts
index 61ac6b3..e64412c 100644
--- a/test/contracts/miksi.test.ts
+++ b/test/contracts/miksi.test.ts
@@ -41,9 +41,9 @@ contract("miksi", (accounts) => {
     let commitment;
     let proof;
     let publicSignals;
+    let commitmentsArray;
 
   before(async () => {
-
     insDepositVerifier = await DepositVerifier.new();
     insWithdrawVerifier = await WithdrawVerifier.new();
     insMiksi = await Miksi.new(insDepositVerifier.address, insWithdrawVerifier.address);
@@ -138,6 +138,17 @@ contract("miksi", (accounts) => {
     let res = await insMiksi.getCommitments();
     expect(res[0][0].toString()).to.be.equal('189025084074544266465422070282645213792582195466360448472858620722286781863');
     expect(res[1].toString()).to.be.equal('9328869343897770565751281504295758914771207504252217956739346620422361279598');
+    console.log(res[0]);
+    commitmentsArray = res[0];
+  });
+
+  it("Rebuild the tree from sc commitments", async () => {
+    let treeTmp = await smt.newMemEmptyTrie();
+    await treeTmp.insert(1, 0);
+    for (let i=0; i<commitmentsArray.length; i++) {
+      await treeTmp.insert(commitmentsArray[i], 0);
+    }
+    expect(treeTmp.root).to.be.equal(tree.root);
   });
 
   it("Calculate witness and generate the zkProof", async () => {