From c21f431673e45b1ab201de48c596cc71f06512e8 Mon Sep 17 00:00:00 2001
From: Noah Citron <noah@jeff.org>
Date: Fri, 19 Aug 2022 18:02:06 -0400
Subject: [PATCH] verify mpt proofs

---
 src/main.rs  |  6 +++---
 src/proof.rs | 50 +++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index e6ae779..e48b1ed 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,9 +22,9 @@ async fn main() -> Result<()> {
     // let payload = client.get_execution_payload().await?;
     // println!("verified execution block hash: {}", hex::encode(payload.block_hash));
 
-    let proof = get_proof("0xf6401adc23Faa6B9AD83eA8604CA7254CB7F53e7", 15365978).await?;
-    verify(&proof)?;
-    // println!("{:?}", proof);
+    let proof = get_proof("0x88A83e0F661447576fb1f50e5d90d571E379cd72", 15365981).await?;
+    let is_valid = verify(&proof);
+    println!("{:?}", is_valid);
 
     Ok(())
 }
diff --git a/src/proof.rs b/src/proof.rs
index 67f9fa6..a2eaeb0 100644
--- a/src/proof.rs
+++ b/src/proof.rs
@@ -3,7 +3,7 @@ use eyre::Result;
 use serde::Deserialize;
 use serde::de::Error;
 use jsonrpsee::{http_client::HttpClientBuilder, rpc_params, core::client::ClientT};
-use ethers::utils::rlp::RlpStream;
+use ethers::utils::rlp::{RlpStream, decode_list};
 use ethers::prelude::{U256, H256, Address};
 use super::utils::hex_str_to_bytes;
 
@@ -15,16 +15,52 @@ pub async fn get_proof(address: &str, block: u64) -> Result<Proof> {
     Ok(client.request("eth_getProof", params).await?)
 }
 
-pub fn verify(proof: &Proof) -> Result<()> {
+pub fn verify_proof(proof: &Vec<Vec<u8>>, root: &Vec<u8>, path: &Vec<u8>, value: &Vec<u8>) -> bool {
 
-    let account_encoded = encode_account(proof);
-    println!("{:?}", account_encoded);
+    // let account_encoded = encode_account(proof);
+    // let state_root = hex_str_to_bytes("0x1d006918a3fef7ff7c843f20747c757a38a0a13fe7723f53e349f462c2cfdd71").unwrap();
+    // let path = keccak256(proof.address).to_vec();
 
-    let state_root = hex_str_to_bytes("0xeb5eb01bd4f503a5698d136c75b37ef2660d6842bf77d0453f2a7fa4a6780d91")?;
-    let address_hash = keccak256(proof.address);
+    let mut expected_hash = root;
+    let mut path_offset = 0;
 
+    for (i, node) in proof.iter().enumerate() {
+        if expected_hash != &keccak256(node).to_vec() {
+            return false;
+        }
 
-    Ok(())
+        let node_list: Vec<Vec<u8>> = decode_list(node);
+        
+        if node_list.len() == 17 {
+
+            let nibble = get_nibble(&path, path_offset);
+            expected_hash = &node_list[nibble as usize].clone();
+
+            path_offset += 1;
+
+        } else if node_list.len() == 2 {
+            if i == proof.len() - 1 {
+                if &node_list[1] != value {
+                    return false;
+                }
+            } else {
+                expected_hash = &node_list[1].clone();
+            }
+        } else {
+            return false;
+        }
+    }
+
+    true
+}
+
+fn get_nibble(path: &Vec<u8>, offset: usize) -> u8 {
+    let byte = path[offset / 2];
+    if offset % 2 == 0 {
+        byte >> 4
+    } else {
+        byte & 0xF
+    }
 }
 
 fn encode_account(proof: &Proof) -> Vec<u8> {