diff --git a/src/silentpayments.rs b/src/silentpayments.rs
index c7e7ba3..f98ef00 100644
--- a/src/silentpayments.rs
+++ b/src/silentpayments.rs
@@ -1,14 +1,16 @@
 use std::collections::HashMap;
+use std::io::Write;
 use std::str::FromStr;
 
 use anyhow::{Error, Result};
 
-use rand::{thread_rng, Rng, RngCore};
+use rand::{thread_rng, Rng};
+use sp_client::bitcoin::hashes::{sha256, Hash};
 use sp_client::bitcoin::hex::FromHex;
 use sp_client::bitcoin::psbt::raw;
-use sp_client::bitcoin::{Psbt, Transaction};
+use sp_client::bitcoin::{Psbt, Transaction, Txid};
 use sp_client::bitcoin::{Amount, OutPoint};
-use sp_client::bitcoin::consensus::{deserialize, serialize};
+use sp_client::bitcoin::consensus::deserialize;
 use sp_client::silentpayments::sending::SilentPaymentAddress;
 use sp_client::spclient::{OwnedOutput, Recipient, SpClient, SpWallet};
 use sp_client::constants;
@@ -74,6 +76,7 @@ pub fn create_transaction_spend_outpoint(
     outpoint: &OutPoint,
     sp_wallet: &SpWallet,
     mut recipient: Recipient,
+    commited_in_txid: &Txid,
     fee_rate: Amount
 ) -> Result<Psbt> {
     let available_outpoints = sp_wallet.get_outputs().to_spendable_list();
@@ -99,18 +102,25 @@ pub fn create_transaction_spend_outpoint(
     // update the amount for the recipient
     recipient.amount = total_available;
 
-    // create a dummy commitment
+    // Take the recipient address
+    let address = recipient.address.clone();
+
+    // create a dummy commitment that is H(b_scan | commited_in txid)
     let mut buf = [0u8;64];
-    thread_rng().fill_bytes(&mut buf);
+    buf[..32].copy_from_slice(commited_in_txid.as_raw_hash().as_byte_array());
+    buf[32..].copy_from_slice(&sp_wallet.get_client().get_scan_key().secret_bytes());
+ 
+    let mut engine = sha256::HashEngine::default();
+    engine.write_all(&buf)?;
+    let hash = sha256::Hash::from_engine(engine);
 
     let mut new_psbt = sp_wallet.get_client().create_new_psbt(
         inputs,
         vec![recipient],
-        Some(&buf),
+        Some(hash.as_byte_array()),
     )?;
 
-    let change_addr = sp_wallet.get_client().sp_receiver.get_change_address();
-    SpClient::set_fees(&mut new_psbt, fee_rate, change_addr)?;
+    SpClient::set_fees(&mut new_psbt, fee_rate, address)?;
 
     let partial_secret = sp_wallet
         .get_client()