Update READMEs and fix paths

- Root README: better basic ops formatting, fix zk-id path
- zk-merkle-proof README: reformatted with proper structure
- zk-nullifier README: clearer intro explaining nullifier properties
- zk-id: update program ID, dependencies

Author: tilo-14

README.md

@@ -12,16 +12,18 @@
 For simple client side distribution visit [this example](https://github.com/Lightprotocol/example-token-distribution).
 
 ### Basic Operations
-- **[create-nullifier](./basic-operations/anchor/create-nullifier)** - Basic Anchor example to create nullifiers.
-- **[basic-operations/anchor](./basic-operations/anchor/)** - Anchor program with Rust and TypeScript tests
-- **[basic-operations/native-rust](./basic-operations/native-rust/)** - Native Solana program with light-sdk and Rust tests.
 
-Basic Operations include:
-- **create** - Initialize a new compressed account.
-- **update** - Modify data in an existing compressed account.
-- **close** - Clear account data and preserve its address.
-- **reinit** - Reinitialize a closed account with the same address.
-- **burn** - Permanently delete a compressed account.
+- **[create-nullifier](./basic-operations/anchor/create-nullifier)** - Basic Anchor example to create nullifiers for payments.
+- **create** - Initialize a new compressed account
+  - [Anchor](./basic-operations/anchor/create) | [Native](./basic-operations/native/programs/create)
+- **update** - Modify data in an existing compressed account
+  - [Anchor](./basic-operations/anchor/update) | [Native](./basic-operations/native/programs/update)
+- **close** - Clear account data and preserve its address
+  - [Anchor](./basic-operations/anchor/close) | [Native](./basic-operations/native/programs/close)
+- **reinit** - Reinitialize a closed account with the same address
+  - [Anchor](./basic-operations/anchor/reinit) | [Native](./basic-operations/native/programs/reinit)
+- **burn** - Permanently delete a compressed account
+  - [Anchor](./basic-operations/anchor/burn) | [Native](./basic-operations/native/programs/burn)
 
 ### Counter Program
 
@@ -47,7 +49,7 @@ Full compressed account lifecycle (create, increment, decrement, reset, close):
 
 ### zk-id Program
 
-- **[zk-id](./zk-id)** - A minimal zk id Solana program that uses zero-knowledge proofs for identity verification with compressed accounts.
+- **[zk-id](./zk/zk-id)** - A minimal zk id Solana program that uses zero-knowledge proofs for identity verification with compressed accounts.
 
 
 ## Light Protocol dependencies

zk/zk-id/package-lock.json

@@ -13,6 +13,8 @@
     "test": "ts-mocha -p ./tsconfig.json -t 1000000 tests/**/*.ts"
   },
   "dependencies": {
+    "@coral-xyz/borsh": "^0.30.1",
+    "@noble/hashes": "^1.3.2",
     "circomlib": "2.0.5",
     "circomlibjs": "0.1.7",
     "@coral-xyz/anchor": "0.31.1",

zk/zk-id/package.json

@@ -20,10 +20,10 @@ use light_sdk::{
 };
 use light_sdk_types::CpiSigner;
 
-declare_id!("HNqStLMpNuNJqhBF1FbGTKHEFbBLJmq8RdJJmZKWz6jH");
+declare_id!("8HYAuAkoLp2UG4mgkqUcJBXo2bzaaKy8nBL62L4S3SSB");
 
 pub const LIGHT_CPI_SIGNER: CpiSigner =
-    derive_light_cpi_signer!("HNqStLMpNuNJqhBF1FbGTKHEFbBLJmq8RdJJmZKWz6jH");
+    derive_light_cpi_signer!("8HYAuAkoLp2UG4mgkqUcJBXo2bzaaKy8nBL62L4S3SSB");
 
 pub const ISSUER: &[u8] = b"issuer";
 pub const CREDENTIAL: &[u8] = b"credential";

zk/zk-id/src/lib.rs

@@ -1,44 +1,82 @@
-# Merkle Proof for ZK Applications
+# Minimal Merkle Proof Example
 
-A simple example program that verifies ZK proofs of compressed account existence in a Merkle tree.
+Proves compressed account existence without revealing the Merkle path or leaf position.
 
-## Instructions
+The prover knows which account exists in the state tree. The verifier only learns that some account with the given data hash exists - not where it is or how to find it.
 
-| Instruction | Description |
-|-------------|-------------|
-| `create_account` | Creates compressed account with address and data hash |
-| `verify_account` | Verifies ZK proof of account existence in state tree |
+## Program Instructions
+
+### 1. `create_account`
+
+Creates a compressed account with a data hash. The account is stored in Light Protocol's state Merkle tree.
+
+### 2. `verify_account`
+
+Verifies a Groth16 proof that the account exists in the state tree. Does not modify state - only checks the proof against the current Merkle root.
+
+**Properties:**
+
+- The Merkle path (26 siblings) stays private
+- The leaf position stays private
+- The account address stays private
+- Only the data hash, discriminator, and Merkle root are public
 
 ## Circuit
 
-5 public inputs: `owner_hashed`, `merkle_tree_hashed`, `discriminator`, `data_hash`, `expectedRoot`
+5 public inputs:
+
+- `owner_hashed` - program ID
+- `merkle_tree_hashed` - state tree pubkey
+- `discriminator` - account type
+- `data_hash` - account data
+- `expectedRoot` - current Merkle root
+
+Account hash:
 
-Account hash computation:
 ```
-hash = Poseidon(owner_hashed, leaf_index, merkle_tree_hashed, address, discriminator + DOMAIN, data_hash)
+Poseidon(owner_hashed, leaf_index, merkle_tree_hashed, address, discriminator + DOMAIN, data_hash)
 ```
 
-## Project Structure
+## Setup
 
+```bash
+./scripts/setup.sh
 ```
-zk-merkle-proof/
-├── circuits/
-│   ├── account_merkle_proof.circom
-│   ├── compressed_account.circom
-│   └── merkle_proof.circom
-├── src/lib.rs
-├── tests/test.rs
-└── scripts/setup.sh
+
+This script will:
+
+1. Install npm dependencies
+2. Download the Powers of Tau ceremony file
+3. Compile the circom circuit
+4. Generate the proving key (zkey)
+5. Export the verification key
+
+## Build and Test
+
+**Build:**
+
+```bash
+cargo build-sbf
 ```
 
-## Build & Test
+**Rust tests:**
 
 ```bash
-./scripts/setup.sh
-cargo build-sbf && cargo test-sbf
+cargo test-sbf -- --nocapture
 ```
 
-## See Also
+## Structure
 
-- [zk-id](../zk-id) - Credential verification with nullifiers
-- [zk-nullifier](../zk-nullifier) - Nullifier example with batch support
+```
+zk-merkle-proof/
+├── circuits/
+│   ├── account_merkle_proof.circom  # Main circuit
+│   ├── compressed_account.circom    # Account hash computation
+│   └── merkle_proof.circom          # 26-level tree traversal
+├── src/
+│   └── lib.rs                       # Solana program with Groth16 verification
+├── tests/
+│   └── test.rs                      # Rust integration tests
+└── scripts/
+    └── setup.sh                     # Circuit compilation and setup
+```