update & some fixes & travis

4 years ago · 0e84b1172e
4 changed files with 287 additions and 239 deletions
--- a/.travis.yml
+++ b/.travis.yml
@ -0,0 +1,9 @@
 language: rust
 rust:
 - stable

 cache:
 - cargo

 script:
 - RUST_BACKTRACE=1 cargo test --all
--- a/README.md
+++ b/README.md
@ -1,8 +1,10 @@
 # merkletree-rs
 # merkletree-rs [![Build Status](https://travis-ci.org/arnaucube/merkletree-rs.svg?branch=master)](https://travis-ci.org/arnaucube/merkletree-rs)
 Sparse MerkleTree implementation in Rust.

 The MerkleTree is optimized in the design and concepts, to have a faster and lighter MerkleTree, maintaining compatibility with a non optimized MerkleTree. In this way, the MerkleRoot of the optimized MerkleTree will be the same that the MerkleRoot of the non optimized MerkleTree.

 Compatible with the Go version: https://github.com/arnaucube/go-merkletree


 ## Usage
 Create new tree:
--- a/src/lib.rs
+++ b/src/lib.rs
@ -9,6 +9,8 @@ extern crate rustc_hex;

 extern crate hex;

 use rustc_hex::ToHex;

 mod utils;
 mod node;

@ -48,12 +50,12 @@ pub struct Db {
   storage: HashMap<[u8;32], Vec<u8>>,
 }
 impl Db {
   pub fn insert(&mut self, k: [u8; 32], t: u8, il: u32, b: &mut Vec<u8>) {
   pub fn insert(&mut self, k: [u8; 32], t: u8, il: u32, b: Vec<u8>) {
      let mut v: Vec<u8>;
      v = [t].to_vec();
      let il_bytes = il.to_le_bytes();
      v.append(&mut il_bytes.to_vec()); // il_bytes are [u8;4] (4 bytes)
      v.append(b);
      v.extend(il_bytes.to_vec()); // il_bytes are [u8;4] (4 bytes)
      v.extend(&b);
      self.storage.insert(k, v);
   }
   pub fn get(&self, k: &[u8;32]) -> (u8, u32, Vec<u8>) {
@ -102,9 +104,9 @@ impl MerkleTree {
      #![allow(unused_variables)]
      #[allow(dead_code)]

      // println!("adding value: {:?}", v.bytes());
      let leaf_node_string = String::from_utf8_lossy(&v.bytes());
      // add the leaf that we are adding
      self.sto.insert(v.ht(), TYPENODEVALUE, v.index_length(), &mut v.bytes().to_vec());
      self.sto.insert(v.ht(), TYPENODEVALUE, v.index_length(), v.bytes().to_vec());

      let index = v.index_length() as usize;
      let hi = v.hi();
@ -123,13 +125,14 @@ impl MerkleTree {
            let path_child = utils::get_path(self.num_levels, hi_child);
            let pos_diff = utils::compare_paths(&path_child, &path);
            if pos_diff == 999 { // TODO use a match here, and instead of 999 return something better
               println!("node already exists");
               println!("compare paths err");
               return;
            }
            let final_node_1_hash = utils::calc_hash_from_leaf_and_level(pos_diff, &path_child, utils::hash_vec(node_bytes.to_vec()));
            self.sto.insert(final_node_1_hash, TYPENODEFINAL, il, &mut node_bytes.to_vec());
            self.sto.insert(final_node_1_hash, TYPENODEFINAL, il, node_bytes.to_vec());
            let final_node_2_hash = utils::calc_hash_from_leaf_and_level(pos_diff, &path, v.ht());
            self.sto.insert(final_node_2_hash, TYPENODEFINAL, v.index_length(), &mut v.bytes().to_vec());
            self.sto.insert(final_node_2_hash, TYPENODEFINAL, v.index_length(), v.bytes().to_vec());

            // parent node
            let parent_node: node::TreeNode;
@ -138,24 +141,25 @@ impl MerkleTree {
                  child_l: final_node_1_hash,
                  child_r: final_node_2_hash,
               }} else {
               parent_node = node::TreeNode {
                  child_l: final_node_2_hash,
                  child_r: final_node_1_hash,
               }}
                  parent_node = node::TreeNode {
                     child_l: final_node_2_hash,
                     child_r: final_node_1_hash,
                  }}
            let empties = utils::get_empties_between_i_and_pos(i, pos_diff+1);
            for empty in &empties {
               siblings.push(*empty);
            }

            let path_from_pos_diff = utils::cut_path(&path, (pos_diff +1) as usize);
            self.root = self.replace_leaf(path_from_pos_diff, siblings.clone(), parent_node.ht(), TYPENODENORMAL, 0, &mut parent_node.bytes().to_vec());
            let path_from_pos_diff = utils::cut_path(&path, (pos_diff + 1) as usize);

            self.root = self.replace_leaf(path_from_pos_diff, &siblings, parent_node.ht(), TYPENODENORMAL, 0, parent_node.bytes().to_vec());
            return;
         }

         let node = node::parse_node_bytes(node_bytes);

         let sibling: [u8;32];
         if path[i as usize] {
         if !path[i as usize] {
            node_hash = node.child_l;
            sibling = node.child_r;
         } else {
@ -166,38 +170,38 @@ impl MerkleTree {
         if node_hash == EMPTYNODEVALUE {
            if i==self.num_levels-2 && siblings[siblings.len()-1]==EMPTYNODEVALUE {
               let final_node_hash = utils::calc_hash_from_leaf_and_level(i+1, &path, v.ht());
               self.sto.insert(final_node_hash, TYPENODEFINAL, v.index_length(), &mut v.bytes().to_vec());
               self.sto.insert(final_node_hash, TYPENODEFINAL, v.index_length(), v.bytes().to_vec());
               self.root = final_node_hash;
               return;
            }
            let final_node_hash = utils::calc_hash_from_leaf_and_level(i, &path, v.ht());
            let path_from_i = utils::cut_path(&path, i as usize);
            self.root = self.replace_leaf(path_from_i, siblings.clone(), final_node_hash, TYPENODEFINAL, v.index_length(), &mut v.bytes().to_vec());
            self.root = self.replace_leaf(path_from_i, &siblings, final_node_hash, TYPENODEFINAL, v.index_length(), v.bytes().to_vec());
            return;
         }
      }
      self.root = self.replace_leaf(path, siblings, v.ht(), TYPENODEVALUE, v.index_length(), &mut v.bytes().to_vec());
      self.root = self.replace_leaf(path, &siblings, v.ht(), TYPENODEVALUE, v.index_length(), v.bytes().to_vec());
   }

   #[allow(dead_code)]
   pub fn replace_leaf(&mut self, path: Vec<bool>, siblings: Vec<[u8;32]>, leaf_hash: [u8;32], node_type: u8, index_length: u32, leaf_value: &mut Vec<u8>) -> [u8;32] {
   pub fn replace_leaf(&mut self, path: Vec<bool>, siblings: &Vec<[u8;32]>, leaf_hash: [u8;32], node_type: u8, index_length: u32, leaf_value: Vec<u8>) -> [u8;32] {
      self.sto.insert(leaf_hash, node_type, index_length, leaf_value);
      let mut curr_node = leaf_hash;

      for i in 0..siblings.len() {
         if path[i as usize] {
         if !path[i as usize] {
            let node = node::TreeNode {
               child_l: curr_node,
               child_r: siblings[siblings.len()-1-i],
            };
            self.sto.insert(node.ht(), TYPENODENORMAL, 0, &mut node.bytes());
            self.sto.insert(node.ht(), TYPENODENORMAL, 0, node.bytes());
            curr_node = node.ht();
         } else {
            let node = node::TreeNode {
               child_l: siblings[siblings.len()-1-i],
               child_r: curr_node,
            };
            self.sto.insert(node.ht(), TYPENODENORMAL, 0, &mut node.bytes());
            self.sto.insert(node.ht(), TYPENODENORMAL, 0, node.bytes());
            curr_node = node.ht();
         }
      }
@ -226,165 +230,161 @@ impl MerkleTree {
         } else {
            node_hash = node.child_r;
         }
         }
         let (_t, _il, node_bytes) = self.sto.get(&node_hash);
         node_bytes
      }
      let (_t, _il, node_bytes) = self.sto.get(&node_hash);
      node_bytes
   }

   #[allow(dead_code)]
   pub fn generate_proof(&self, hi: [u8;32]) -> Vec<u8> {
      let mut mp: Vec<u8> = Vec::new();

      let mut empties: [u8;32] = [0;32];
      let path = utils::get_path(self.num_levels, hi);

      let mut siblings: Vec<[u8;32]> = Vec::new();
      let mut node_hash = self.root;

      for i in 0..self.num_levels {
         let (t, il, node_bytes) = self.sto.get(&node_hash);
         if t == TYPENODEFINAL {
            let real_value_in_pos = self.get_value_in_pos(hi);
            if real_value_in_pos == EMPTYNODEVALUE {
               let leaf_hi = utils::hash_vec(node_bytes.to_vec().split_at(il as usize).0.to_vec());
               let path_child = utils::get_path(self.num_levels, leaf_hi);
               let pos_diff = utils::compare_paths(&path_child, &path);
               if pos_diff == self.num_levels { // TODO use a match here, and instead of 999 return something better
                  return mp;
               }
               if pos_diff != self.num_levels-1-i {
                  let sibling = utils::calc_hash_from_leaf_and_level(pos_diff, &path_child, utils::hash_vec(node_bytes.to_vec()));
                  let mut new_siblings: Vec<[u8;32]> = Vec::new();
                  new_siblings.push(sibling);
                  new_siblings.append(&mut siblings);
                  siblings = new_siblings;
                  // set empties bit
                  let bit_pos = self.num_levels-2-pos_diff;
                  empties[(empties.len() as isize + (bit_pos as isize/8-1) as isize) as usize] |= 1 << (bit_pos%8);
      #[allow(dead_code)]
      pub fn generate_proof(&self, hi: [u8;32]) -> Vec<u8> {
         let mut mp: Vec<u8> = Vec::new();

         let mut empties: [u8;32] = [0;32];
         let path = utils::get_path(self.num_levels, hi);

         let mut siblings: Vec<[u8;32]> = Vec::new();
         let mut node_hash = self.root;

         for i in 0..self.num_levels {
            let (t, il, node_bytes) = self.sto.get(&node_hash);
            if t == TYPENODEFINAL {
               let real_value_in_pos = self.get_value_in_pos(hi);
               if real_value_in_pos == EMPTYNODEVALUE {
                  let leaf_hi = utils::hash_vec(node_bytes.to_vec().split_at(il as usize).0.to_vec());
                  let path_child = utils::get_path(self.num_levels, leaf_hi);
                  let pos_diff = utils::compare_paths(&path_child, &path);
                  if pos_diff == self.num_levels { // TODO use a match here, and instead of 999 return something better
                     return mp;
                  }
                  if pos_diff != self.num_levels-1-i {
                     let sibling = utils::calc_hash_from_leaf_and_level(pos_diff, &path_child, utils::hash_vec(node_bytes.to_vec()));
                     let mut new_siblings: Vec<[u8;32]> = Vec::new();
                     new_siblings.push(sibling);
                     new_siblings.extend(siblings);
                     siblings = new_siblings;
                     // set empties bit
                     let bit_pos = self.num_levels-2-pos_diff;
                     empties[(empties.len() as isize + (bit_pos as isize/8-1) as isize) as usize] |= 1 << (bit_pos%8);
                  }
               }
               break
            }
            let node = node::parse_node_bytes(node_bytes);
            let sibling: [u8;32];
            if !path[self.num_levels as usize -i as usize -2] {
               node_hash = node.child_l;
               sibling = node.child_r;
            } else {
               sibling = node.child_l;
               node_hash = node.child_r;
            }
            if sibling != EMPTYNODEVALUE {
               // set empties bit
               empties[(empties.len() as isize + (i as isize/8-1) as isize) as usize] |= 1 << (i%8);
               let mut new_siblings: Vec<[u8;32]> = Vec::new();
               new_siblings.push(sibling);
               new_siblings.extend(siblings);
               siblings = new_siblings;
            }
            break
         }
         let node = node::parse_node_bytes(node_bytes);
         let sibling: [u8;32];
         if !path[self.num_levels as usize -i as usize -2] {
            node_hash = node.child_l;
            sibling = node.child_r;
         } else {
            sibling = node.child_l;
            node_hash = node.child_r;
         }
         if sibling != EMPTYNODEVALUE {
            // set empties bit
            empties[(empties.len() as isize + (i as isize/8-1) as isize) as usize] |= 1 << (i%8);
            let mut new_siblings: Vec<[u8;32]> = Vec::new();
            new_siblings.push(sibling);
            new_siblings.append(&mut siblings);
            siblings = new_siblings;
         mp.append(&mut empties[..].to_vec());
         for s in siblings {
            mp.append(&mut s.to_vec());
         }
         mp
      }
      mp.append(&mut empties[..].to_vec());
      for s in siblings {
         mp.append(&mut s.to_vec());
      }
      mp
   }
   #[allow(dead_code)]
   pub fn print_level(&self, parent: [u8;32], mut lvl: u32, max_level: u32) {
      use rustc_hex::ToHex;

      let mut line: String = "".to_string();
      for _ in 0..lvl {
         line += &"  ".to_string();
      }
      line += &("lvl ".to_string() + &lvl.to_string());
      line += &(" - '".to_string() + &parent.to_hex() + &"' = ".to_string());
      let (t, _, node_bytes) = self.sto.get(&parent);
      let mut node = node::TreeNode {
         child_l: EMPTYNODEVALUE,
         child_r: EMPTYNODEVALUE,
      };
      if t==TYPENODENORMAL {
         node = node::parse_node_bytes(node_bytes);
         line += &("'".to_string() + &node.child_l.to_hex() + &"' - '".to_string() + &node.child_r.to_hex() + &"'".to_string());
      } else if t == TYPENODEVALUE {
         //
      } else if t == TYPENODEFINAL {
         let hash_node_bytes = utils::hash_vec(node_bytes);
         line += &("[final] final tree node: ".to_string() + &hash_node_bytes.to_hex()+ &"\n".to_string());
         let (_, _, leaf_node_bytes) = self.sto.get(&hash_node_bytes);
      #[allow(dead_code)]
      pub fn print_level(&self, parent: [u8;32], mut lvl: u32, max_level: u32) {
         let mut line: String = "".to_string();
         for _ in 0..lvl {
            line += "  ";
            line += &format!(" ");
         }
         line += &format!("lvl {}", lvl);
         line += &format!(" - '{}'  = ", parent.to_hex());
         let (t, _, node_bytes) = self.sto.get(&parent);
         let mut node = node::TreeNode {
            child_l: EMPTYNODEVALUE,
            child_r: EMPTYNODEVALUE,
         };
         if t==TYPENODENORMAL {
            node = node::parse_node_bytes(node_bytes);
            line += &format!("'{}' - '{}'", node.child_l.to_hex(), node.child_r.to_hex());
         } else if t == TYPENODEVALUE {
            //
         } else if t == TYPENODEFINAL {
            let hash_node_bytes = utils::hash_vec(node_bytes);
            line += &format!("[final] final tree node: {} \n", hash_node_bytes.to_hex());
            let (_, _, leaf_node_bytes) = self.sto.get(&hash_node_bytes);
            for _ in 0..lvl {
               line += "  ";
            }
            let leaf_node_string = String::from_utf8_lossy(&leaf_node_bytes);
            line += &format!("leaf value: {}", leaf_node_string);
         } else {
            line += "[EMPTY Branch]"
         }
         println!("{}", line);
         lvl += 1;
         if node.child_r.len()>0 && lvl<max_level && t != TYPENODEEMPTY && t != TYPENODEFINAL {
            self.print_level(node.child_l, lvl, max_level);
            self.print_level(node.child_r, lvl, max_level);
         }
         let leaf_node_string = String::from_utf8_lossy(&leaf_node_bytes);
         line += &("leaf value: ".to_string() + &leaf_node_string);
      } else {
         line += &"[EMPTY Branch]".to_string()
      }
      println!("{:?}", line);
      lvl += 1;
      if node.child_r.len()>0 && lvl<max_level && t != TYPENODEEMPTY && t != TYPENODEFINAL {
         self.print_level(node.child_l, lvl, max_level);
         self.print_level(node.child_r, lvl, max_level);
      pub fn print_full_tree(&self) {
         self.print_level(self.root, 0, self.num_levels - 1);
         println!("root {:?}", self.root.to_hex());
      }
      pub fn print_levels_tree(&self, max_level: u32) {
         self.print_level(self.root, 0, self.num_levels - 1 - max_level);
         println!("root {:?}", self.root.to_hex());
      }
   }
   pub fn print_full_tree(&self) {
      use rustc_hex::ToHex;
      self.print_level(self.root, 0, self.num_levels - 1);
      println!("root {:?}", self.root.to_hex());
   }
   pub fn print_levels_tree(&self, max_level: u32) {
      use rustc_hex::ToHex;
      self.print_level(self.root, 0, self.num_levels - 1 - max_level);
      println!("root {:?}", self.root.to_hex());
   }
 }
 #[allow(dead_code)]
 pub fn verify_proof(root: [u8;32], mp: Vec<u8>, hi: [u8;32], ht: [u8;32], num_levels: u32) -> bool {
   let empties: Vec<u8>;
   empties = mp.split_at(32).0.to_vec();

   let mut siblings: Vec<[u8;32]> = Vec::new();
   for i in (empties.len()..mp.len()).step_by(EMPTYNODEVALUE.len()) {
      let mut sibling: [u8;32] = [0;32];
      sibling.copy_from_slice(&mp[i..i+EMPTYNODEVALUE.len()]);
      siblings.push(sibling);
   }
   pub fn verify_proof(root: [u8;32], mp: Vec<u8>, hi: [u8;32], ht: [u8;32], num_levels: u32) -> bool {
      let empties: Vec<u8>;
      empties = mp.split_at(32).0.to_vec();

   let path = utils::get_path(num_levels, hi);
   let mut node_hash = ht;
   let mut sibling_used_pos = 0;

   for i in (0..=num_levels-2).rev() {
      let sibling: [u8;32];
      if (empties[empties.len()-i as usize/8-1] & (1 << (i%8))) > 0 {
         sibling = siblings[sibling_used_pos];
         sibling_used_pos += 1;
      } else {
         sibling = EMPTYNODEVALUE;
      let mut siblings: Vec<[u8;32]> = Vec::new();
      for i in (empties.len()..mp.len()).step_by(EMPTYNODEVALUE.len()) {
         let mut sibling: [u8;32] = [0;32];
         sibling.copy_from_slice(&mp[i..i+EMPTYNODEVALUE.len()]);
         siblings.push(sibling);
      }

      let n: node::TreeNode;
      if path[num_levels as usize - i as usize-2] {
         n = node::TreeNode {
            child_l: sibling,
            child_r: node_hash,
         }} else {
         n = node::TreeNode {
            child_l: node_hash,
            child_r: sibling,
         }}
      if node_hash == EMPTYNODEVALUE && sibling == EMPTYNODEVALUE {
         node_hash = EMPTYNODEVALUE;
      } else {
         node_hash = n.ht();
      let path = utils::get_path(num_levels, hi);
      let mut node_hash = ht;
      let mut sibling_used_pos = 0;

      for i in (0..=num_levels-2).rev() {
         let sibling: [u8;32];
         if (empties[empties.len()-i as usize/8-1] & (1 << (i%8))) > 0 {
            sibling = siblings[sibling_used_pos];
            sibling_used_pos += 1;
         } else {
            sibling = EMPTYNODEVALUE;
         }

         let n: node::TreeNode;
         if path[num_levels as usize - i as usize-2] {
            n = node::TreeNode {
               child_l: sibling,
               child_r: node_hash,
            }} else {
               n = node::TreeNode {
                  child_l: node_hash,
                  child_r: sibling,
               }}
         if node_hash == EMPTYNODEVALUE && sibling == EMPTYNODEVALUE {
            node_hash = EMPTYNODEVALUE;
         } else {
            node_hash = n.ht();
         }
      }
      if node_hash==root {
         return true;
      }
      false
   }
   if node_hash==root {
      return true;
   }
   false
 }


 #[cfg(test)]
@ -433,83 +433,86 @@ pub fn verify_proof(root: [u8;32], mp: Vec, hi: [u8;32], ht: [u8;32], num_le
         assert_eq!(*val.bytes(), b);
         assert_eq!("a0e72cc948119fcb71b413cf5ada12b2b825d5133299b20a6d9325ffc3e2fbf1", mt.root.to_hex());
      }

      #[test]
      fn test_add_2() {
          let mut mt: MerkleTree = new(140);
          let val = TestValue {
              bytes: "this is a test leaf".as_bytes().to_vec(),
              index_length: 15,
          };
          assert_eq!("0000000000000000000000000000000000000000000000000000000000000000", mt.root.to_hex());
          mt.add(&val);
          let (_t, _il, b) = mt.sto.get(&val.ht());
          assert_eq!(*val.bytes(), b);
          assert_eq!("b4fdf8a653198f0e179ccb3af7e4fc09d76247f479d6cfc95cd92d6fda589f27", mt.root.to_hex());
          let val2 = TestValue {
              bytes: "this is a second test leaf".as_bytes().to_vec(),
              index_length: 15,
          };
          mt.add(&val2);
          let (_t, _il, b) = mt.sto.get(&val2.ht());
          assert_eq!(*val2.bytes(), b);
          assert_eq!("8ac95e9c8a6fbd40bb21de7895ee35f9c8f30ca029dbb0972c02344f49462e82", mt.root.to_hex());
          mt.print_full_tree();
         let mut mt: MerkleTree = new(140);
         let val = TestValue {
            bytes: "this is a test leaf".as_bytes().to_vec(),
            index_length: 15,
         };
         assert_eq!("0000000000000000000000000000000000000000000000000000000000000000", mt.root.to_hex());
         mt.add(&val);
         let (_t, _il, b) = mt.sto.get(&val.ht());
         assert_eq!(*val.bytes(), b);
         assert_eq!("b4fdf8a653198f0e179ccb3af7e4fc09d76247f479d6cfc95cd92d6fda589f27", mt.root.to_hex());
         let val2 = TestValue {
            bytes: "this is a second test leaf".as_bytes().to_vec(),
            index_length: 15,
         };
         mt.add(&val2);
         let (_t, _il, b) = mt.sto.get(&val2.ht());
         assert_eq!(*val2.bytes(), b);
         assert_eq!("8ac95e9c8a6fbd40bb21de7895ee35f9c8f30ca029dbb0972c02344f49462e82", mt.root.to_hex());
      }

      #[test]
      fn test_generate_proof_and_verify_proof() {
          let mut mt: MerkleTree = new(140);
          let val = TestValue {
              bytes: "this is a test leaf".as_bytes().to_vec(),
              index_length: 15,
          };
          assert_eq!("0000000000000000000000000000000000000000000000000000000000000000", mt.root.to_hex());
          mt.add(&val);
          let (_t, _il, b) = mt.sto.get(&val.ht());
          assert_eq!(*val.bytes(), b);
          assert_eq!("b4fdf8a653198f0e179ccb3af7e4fc09d76247f479d6cfc95cd92d6fda589f27", mt.root.to_hex());
          let val2 = TestValue {
              bytes: "this is a second test leaf".as_bytes().to_vec(),
              index_length: 15,
          };
          mt.add(&val2);
          let (_t, _il, b) = mt.sto.get(&val2.ht());
          assert_eq!(*val2.bytes(), b);
          assert_eq!("8ac95e9c8a6fbd40bb21de7895ee35f9c8f30ca029dbb0972c02344f49462e82", mt.root.to_hex());
      
          let mp = mt.generate_proof(val2.hi());
          assert_eq!("0000000000000000000000000000000000000000000000000000000000000001fd8e1a60cdb23c0c7b2cf8462c99fafd905054dccb0ed75e7c8a7d6806749b6b", mp.to_hex());

          // verify
          let v = verify_proof(mt.root, mp, val2.hi(), val2.ht(), mt.num_levels);
          assert_eq!(true, v);
         let mut mt: MerkleTree = new(140);
         let val = TestValue {
            bytes: "this is a test leaf".as_bytes().to_vec(),
            index_length: 15,
         };
         assert_eq!("0000000000000000000000000000000000000000000000000000000000000000", mt.root.to_hex());
         mt.add(&val);
         let (_t, _il, b) = mt.sto.get(&val.ht());
         assert_eq!(*val.bytes(), b);
         assert_eq!("b4fdf8a653198f0e179ccb3af7e4fc09d76247f479d6cfc95cd92d6fda589f27", mt.root.to_hex());
         let val2 = TestValue {
            bytes: "this is a second test leaf".as_bytes().to_vec(),
            index_length: 15,
         };
         mt.add(&val2);
         let (_t, _il, b) = mt.sto.get(&val2.ht());
         assert_eq!(*val2.bytes(), b);
         assert_eq!("8ac95e9c8a6fbd40bb21de7895ee35f9c8f30ca029dbb0972c02344f49462e82", mt.root.to_hex());

         let mp = mt.generate_proof(val2.hi());
         assert_eq!("0000000000000000000000000000000000000000000000000000000000000001fd8e1a60cdb23c0c7b2cf8462c99fafd905054dccb0ed75e7c8a7d6806749b6b", mp.to_hex());

         // verify
         let v = verify_proof(mt.root, mp, val2.hi(), val2.ht(), mt.num_levels);
         assert_eq!(true, v);
      }

      #[test]
      fn test_generate_proof_empty_leaf_and_verify_proof() {
          let mut mt: MerkleTree = new(140);
          let val = TestValue {
              bytes: "this is a test leaf".as_bytes().to_vec(),
              index_length: 15,
          };
          mt.add(&val);
          let val2 = TestValue {
              bytes: "this is a second test leaf".as_bytes().to_vec(),
              index_length: 15,
          };
          mt.add(&val2);
          assert_eq!("8ac95e9c8a6fbd40bb21de7895ee35f9c8f30ca029dbb0972c02344f49462e82", mt.root.to_hex());
         let mut mt: MerkleTree = new(140);
         let val = TestValue {
            bytes: "this is a test leaf".as_bytes().to_vec(),
            index_length: 15,
         };
         mt.add(&val);
         let val2 = TestValue {
            bytes: "this is a second test leaf".as_bytes().to_vec(),
            index_length: 15,
         };
         mt.add(&val2);
         assert_eq!("8ac95e9c8a6fbd40bb21de7895ee35f9c8f30ca029dbb0972c02344f49462e82", mt.root.to_hex());

         // proof of empty leaf
          let val3 = TestValue {
              bytes: "this is a third test leaf".as_bytes().to_vec(),
              index_length: 15,
          };
          let mp = mt.generate_proof(val3.hi());
          assert_eq!("000000000000000000000000000000000000000000000000000000000000000389741fa23da77c259781ad8f4331a5a7d793eef1db7e5200ddfc8e5f5ca7ce2bfd8e1a60cdb23c0c7b2cf8462c99fafd905054dccb0ed75e7c8a7d6806749b6b", mp.to_hex());

          // verify that is a proof of an empty leaf (EMPTYNODEVALUE)
          let v = verify_proof(mt.root, mp, val3.hi(), EMPTYNODEVALUE, mt.num_levels);
          assert_eq!(true, v);
         let val3 = TestValue {
            bytes: "this is a third test leaf".as_bytes().to_vec(),
            index_length: 15,
         };
         let mp = mt.generate_proof(val3.hi());
         assert_eq!("000000000000000000000000000000000000000000000000000000000000000389741fa23da77c259781ad8f4331a5a7d793eef1db7e5200ddfc8e5f5ca7ce2bfd8e1a60cdb23c0c7b2cf8462c99fafd905054dccb0ed75e7c8a7d6806749b6b", mp.to_hex());

         // verify that is a proof of an empty leaf (EMPTYNODEVALUE)
         let v = verify_proof(mt.root, mp, val3.hi(), EMPTYNODEVALUE, mt.num_levels);
         assert_eq!(true, v);
      }

      #[test]
      fn test_harcoded_proofs_of_existing_leaf() {
         // check proof of value in leaf
@ -520,9 +523,10 @@ pub fn verify_proof(root: [u8;32], mp: Vec, hi: [u8;32], ht: [u8;32], num_le
         hi.copy_from_slice(&hex::decode("786677808ba77bdd9090a969f1ef2cbd1ac5aecd9e654f340500159219106878").unwrap());
         let mut ht: [u8;32] = [0;32];
         ht.copy_from_slice(&hex::decode("786677808ba77bdd9090a969f1ef2cbd1ac5aecd9e654f340500159219106878").unwrap());
          let v = verify_proof(root, mp, hi, ht, 140);
          assert_eq!(true, v);
         let v = verify_proof(root, mp, hi, ht, 140);
         assert_eq!(true, v);
      }

      #[test]
      fn test_harcoded_proofs_of_empty_leaf() {
         // check proof of value in leaf
@ -531,7 +535,41 @@ pub fn verify_proof(root: [u8;32], mp: Vec, hi: [u8;32], ht: [u8;32], num_le
         let mp = hex::decode("0000000000000000000000000000000000000000000000000000000000000004bf8e980d2ed328ae97f65c30c25520aeb53ff837579e392ea1464934c7c1feb9").unwrap();
         let mut hi: [u8;32] = [0;32];
         hi.copy_from_slice(&hex::decode("a69792a4cff51f40b7a1f7ae596c6ded4aba241646a47538898f17f2a8dff647").unwrap());
          let v = verify_proof(root, mp, hi, EMPTYNODEVALUE, 140);
          assert_eq!(true, v);
         let v = verify_proof(root, mp, hi, EMPTYNODEVALUE, 140);
         assert_eq!(true, v);
      }

      #[test]
      fn test_add_leafs_different_order() {
         let mut mt1: MerkleTree = new(140);
         mt1.add(&TestValue {bytes: "0 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt1.add(&TestValue {bytes: "1 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt1.add(&TestValue {bytes: "2 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt1.add(&TestValue {bytes: "3 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt1.add(&TestValue {bytes: "4 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt1.add(&TestValue {bytes: "5 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt1.print_full_tree();


         let mut mt2: MerkleTree = new(140);
         mt2.add(&TestValue {bytes: "2 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt2.add(&TestValue {bytes: "1 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt2.add(&TestValue {bytes: "0 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt2.add(&TestValue {bytes: "5 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt2.add(&TestValue {bytes: "3 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt2.add(&TestValue {bytes: "4 this is a test leaf".as_bytes().to_vec(), index_length: 15,});
         mt2.print_full_tree();

         assert_eq!(mt1.root, mt2.root);
         assert_eq!(mt1.root.to_hex(), "264397f84da141b3134dcde1d7540d27a2bf0d787bbe8365d9ad5c9c18d3c621");
      }

      #[test]
      fn test_add_1000_leafs() {
         let mut mt: MerkleTree = new(140);
         for i in 0..1000 {
            mt.add(&TestValue {bytes: (i.to_string()+" this is a test leaf").as_bytes().to_vec(), index_length: 15,});
         }
         assert_eq!(mt.root.to_hex(), "6e2da580b2920cd78ed8d4e4bf41e209dfc99ef28bc19560042f0ac803e0d6f7");
      }
   }
--- a/src/utils.rs
+++ b/src/utils.rs
@ -2,7 +2,6 @@ use node;
 use tiny_keccak::Keccak;

 pub fn hash_vec(b: Vec<u8>) -> [u8; 32] {
    // let mut sha3 = Keccak::new_sha3_256();
    let mut sha3 = Keccak::new_keccak256();
    sha3.update(&b);
    let mut res: [u8; 32] = [0; 32];
@ -13,7 +12,7 @@ pub fn hash_vec(b: Vec) -> [u8; 32] {
 #[allow(dead_code)]
 pub fn get_path(num_levels: u32, hi: [u8;32]) -> Vec<bool> {
    let mut path = Vec::new();
    for i in (0..num_levels as usize-1).rev() {
    for i in (0..=num_levels as usize-2).rev() {
        path.push((hi[hi.len()-i/8-1] & (1 << (i%8))) > 0);
    }
    path
@ -42,9 +41,9 @@ pub fn calc_hash_from_leaf_and_level(until_level: u32, path: &[bool], leaf_hash:

 pub fn cut_path(path: &[bool], i: usize) -> Vec<bool> {
    let mut path_res: Vec<bool> = Vec::new();
    for (j, path_elem) in path.iter().enumerate() {
        if j >= i {
            path_res.push(*path_elem);
    for j in 0..path.len() {
        if j>=i {
            path_res.push(path[j]);
        }
    }
    path_res
@ -61,7 +60,7 @@ pub fn compare_paths(a: &[bool], b: &[bool]) -> u32 {

 pub fn get_empties_between_i_and_pos(i: u32, pos: u32) -> Vec<[u8;32]> {
    let mut sibl: Vec<[u8;32]> = Vec::new();
    for _ in (pos..i).rev() {
    for _ in (pos..=i).rev() {
        sibl.push(::EMPTYNODEVALUE);
    }
    sibl