Update README.md

README.md

@@ -2,10 +2,13 @@
 
 *From Esperanto, **miksi** (miks·i): to mingle, to blend, to mix, to shuffle*
 
+Ethereum mixer where all the computation & constructions are done offchain and then proved inside a zkSNARK to the Smart Contract (for the *deposit* and for the *withdraw*).
+This means that the client builds a MerkleTree and makes all the needed computation, and then generates a zk-proof where proves that all the offchain computation is done following all the rules (no leaf deletion, only one leaf addition, correct leaf format).
+This allows to use only `~325.000 gas` for the *deposit*, and `~308.000 gas` for the withdraw.
+
 ![](miksi-logo00-small.png)
 
-
-**Warning:** This repository is in a very early stage.
+**Warning:** This repository is in a very early stage. The current version works, but is not finished and there are some improvements to be added.
 
 WebApp to use miksi-core can be found at https://github.com/arnaucube/miksi-app
 
@@ -27,8 +30,10 @@ npm run test-sc
 
 
 ## Spec draft
+**Note:** The spec & code is a work in progress, there are some pending works & improvements planned to do, and some diagrams for better explanation.
 
 ### Deposit
+*All computation & constructions are done offchain and then proved inside a zkSNARK to the Smart Contract*
 - 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)
@@ -39,16 +44,18 @@ npm run test-sc
 - 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)
+	- prover knows the `secret` & `nullifier` for the `commitment` which is in a leaf in the merkletree
+	- the transition from `RootOld` (the current one in the Smart Contract) to `RootNew` has been done following the rules (only one leaf addition, no leaf deletion, correct leaf format, etc)
 - user sends ETH to the smart contract `deposit` call, together with the zkProof data
+- smart contract verifies the zkProof of the deposit, and if everything is ok stores the commitment & the new root
 
 Deposit circuit can be found [here](https://github.com/miksi-labs/miksi-core/blob/master/circuits/deposit.circom).
 
 ### Withdraw
+*All computation & constructions are done offchain and then proved inside a zkSNARK to the Smart Contract*
 - 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 the siblings (merkle proof) 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
@@ -57,3 +64,6 @@ Deposit circuit can be found [here](https://github.com/miksi-labs/miksi-core/blo
 
 Withdraw circuit can be found [here](https://github.com/miksi-labs/miksi-core/blob/master/circuits/withdraw.circom).
 
+
+# Thanks
+Miksi is possible thanks to  [circom](https://github.com/iden3/circom), [circomlib](https://github.com/iden3/circomlib), [wasmsnark](https://github.com/iden3/wasmsnark), and thanks to the ideas about offchain computation validated with a zkSNARK in the [Zexe paper](https://eprint.iacr.org/2018/962.pdf).

circuits/deposit.circom

@@ -55,7 +55,11 @@ template Deposit(nLevels) {
 	comCheck.in[1] <== commitment;
 	comCheck.out === 1;
 
-	// TODO instead of 2 siblings input, get siblingsOld from siblingsNew[len-1]
+	// TODO instead of 2 siblings input, get siblingsOld from
+	// siblingsNew[len-1] both siblingsOld & siblingsNew have same values
+	// except for one, can be merged into one, to ensure that the circuit
+	// checks that the leaf non existing under rootOld is in the same
+	// position than the check that the leaf exists under the rootNew
 
 	// check that nLevels-1 siblings match from siblingsOld & siblingsNew
 	component siblEq[nLevels];

test/contracts/miksi.test.ts

@@ -94,7 +94,7 @@ contract("miksi", (accounts) => {
     commitmentsArray[0] = res[0];
     currKey = res[2];
   });
-  
+
   it("Rebuild the tree from sc commitments", async () => {
     let treeTmp = await smt.newMemEmptyTrie();
     await treeTmp.insert(0, 0);