diff --git a/src/process.rs b/src/process.rs
index 0d2e4bd..ef35fd0 100644
--- a/src/process.rs
+++ b/src/process.rs
@@ -20,6 +20,7 @@ use crate::{
 pub struct ProcessState {
     pub commited_in: OutPoint,
     pub pcd_commitment: Value, // If we can't modify a field, we just copy the previous value
+    pub merkle_root: String, // the root of the tree created with all the commitments. Serves as an unique id for a state too
     pub encrypted_pcd: Value, // Some fields may be clear, if the owner of the process decides so
     pub keys: Map<String, Value>, // We may not always have all the keys
     pub validation_tokens: Vec<Proof>, // Signature of the hash of the encrypted pcd tagged with some decision like "yes" or "no"
@@ -31,14 +32,20 @@ impl ProcessState {
         let mut encrypted = Map::new();
 
         let clear_pcd = Value::Object(clear_state);
-        let commitments = clear_pcd.hash_all_fields(commited_in)?;
+        
+        let sorted_pcd = Value::Object(clear_pcd.to_sorted_key_values()?);
 
-        let keys_to_encrypt: Vec<String> = commitments.keys().map(|k| k.clone()).collect();
-        clear_pcd.encrypt_fields(&keys_to_encrypt, &mut keys, &mut encrypted)?;
+        let pcd_commitment = Value::Object(sorted_pcd.hash_all_fields(commited_in)?);
+
+        let merkle_root = pcd_commitment.create_merkle_tree()?.root().ok_or(anyhow::Error::msg("Invalid merkle tree"))?.to_lower_hex_string();
+
+        let keys_to_encrypt: Vec<String> = pcd_commitment.as_object().unwrap().keys().map(|k| k.clone()).collect();
+        sorted_pcd.encrypt_fields(&keys_to_encrypt, &mut keys, &mut encrypted)?;
 
         let res = Self {
             commited_in,
-            pcd_commitment: Value::Object(commitments),
+            pcd_commitment,
+            merkle_root,
             encrypted_pcd: Value::Object(encrypted),
             keys,
             validation_tokens: vec![],