diff --git a/api/src/owner.rs b/api/src/owner.rs
index 17868ec0a..bc6d96617 100644
--- a/api/src/owner.rs
+++ b/api/src/owner.rs
@@ -482,7 +482,7 @@ where
 	/// 	// Send slate somehow
 	/// 	// ...
 	/// 	// Lock our outputs if we're happy the slate was (or is being) sent
-	/// 	api_owner.tx_lock_outputs(&slate);
+	/// 	api_owner.tx_lock_outputs(&slate, 0);
 	/// }
 	/// ```
 
@@ -513,7 +513,7 @@ where
 						))?;
 					}
 				}
-				self.tx_lock_outputs(&slate)?;
+				self.tx_lock_outputs(&slate, 0)?;
 				let slate = match sa.finalize {
 					true => self.finalize_tx(&slate)?,
 					false => slate,
@@ -645,6 +645,8 @@ where
 	///
 	/// # Arguments
 	/// * `slate` - The transaction [`Slate`](../grin_wallet_libwallet/slate/struct.Slate.html). All
+	/// * `participant_id` - The participant id, generally 0 for the party putting in funds, 1 for the
+	/// party receiving.
 	/// elements in the `input` vector of the `tx` field that are found in the wallet's currently
 	/// active account will be set to status `Locked`
 	///
@@ -676,14 +678,14 @@ where
 	///		// Send slate somehow
 	///		// ...
 	///		// Lock our outputs if we're happy the slate was (or is being) sent
-	///		api_owner.tx_lock_outputs(&slate);
+	///		api_owner.tx_lock_outputs(&slate, 0);
 	/// }
 	/// ```
 
-	pub fn tx_lock_outputs(&self, slate: &Slate) -> Result<(), Error> {
+	pub fn tx_lock_outputs(&self, slate: &Slate, participant_id: usize) -> Result<(), Error> {
 		let mut w = self.wallet.lock();
 		w.open_with_credentials()?;
-		let res = owner::tx_lock_outputs(&mut *w, slate);
+		let res = owner::tx_lock_outputs(&mut *w, slate, participant_id);
 		w.close()?;
 		res
 	}
@@ -734,7 +736,7 @@ where
 	///		// Send slate somehow
 	///		// ...
 	///		// Lock our outputs if we're happy the slate was (or is being) sent
-	///		let res = api_owner.tx_lock_outputs(&slate);
+	///		let res = api_owner.tx_lock_outputs(&slate, 0);
 	///		//
 	///		// Retrieve slate back from recipient
 	///		//
@@ -791,7 +793,7 @@ where
 	///		// Send slate somehow
 	///		// ...
 	///		// Lock our outputs if we're happy the slate was (or is being) sent
-	///		let res = api_owner.tx_lock_outputs(&slate);
+	///		let res = api_owner.tx_lock_outputs(&slate, 0);
 	///		//
 	///		// Retrieve slate back from recipient
 	///		//
@@ -852,7 +854,7 @@ where
 	///		// Send slate somehow
 	///		// ...
 	///		// Lock our outputs if we're happy the slate was (or is being) sent
-	///		let res = api_owner.tx_lock_outputs(&slate);
+	///		let res = api_owner.tx_lock_outputs(&slate, 0);
 	///		//
 	///		// We didn't get the slate back, or something else went wrong
 	///		//
@@ -945,7 +947,7 @@ where
 	///		// Send slate somehow
 	///		// ...
 	///		// Lock our outputs if we're happy the slate was (or is being) sent
-	///		let res = api_owner.tx_lock_outputs(&slate);
+	///		let res = api_owner.tx_lock_outputs(&slate, 0);
 	///		//
 	///		// Retrieve slate back from recipient
 	///		//
diff --git a/api/src/owner_rpc.rs b/api/src/owner_rpc.rs
index 8b2f33f61..aea645afa 100644
--- a/api/src/owner_rpc.rs
+++ b/api/src/owner_rpc.rs
@@ -690,7 +690,8 @@ pub trait OwnerRpc {
 				"orig_version": 2,
 				"version": 2
 				}
-			}
+			},
+			0
 		]
 	}
 	# "#
@@ -708,7 +709,7 @@ pub trait OwnerRpc {
 
 	```
 	 */
-	fn tx_lock_outputs(&self, slate: Slate) -> Result<(), ErrorKind>;
+	fn tx_lock_outputs(&self, slate: Slate, participant_id: usize) -> Result<(), ErrorKind>;
 
 	/**
 	Networked version of [Owner::finalize_tx](struct.Owner.html#method.finalize_tx).
@@ -1293,8 +1294,8 @@ where
 		Owner::finalize_tx(self, &mut slate).map_err(|e| e.kind())
 	}
 
-	fn tx_lock_outputs(&self, mut slate: Slate) -> Result<(), ErrorKind> {
-		Owner::tx_lock_outputs(self, &mut slate).map_err(|e| e.kind())
+	fn tx_lock_outputs(&self, mut slate: Slate, participant_id: usize) -> Result<(), ErrorKind> {
+		Owner::tx_lock_outputs(self, &mut slate, participant_id).map_err(|e| e.kind())
 	}
 
 	fn cancel_tx(&self, tx_id: Option<u32>, tx_slate_id: Option<Uuid>) -> Result<(), ErrorKind> {
@@ -1420,7 +1421,7 @@ pub fn run_doctest_owner(
 		// Spit out slate for input to finalize_tx
 		println!("{}", serde_json::to_string_pretty(&slate).unwrap());
 		if lock_tx {
-			api_impl::owner::tx_lock_outputs(&mut *w, &slate).unwrap();
+			api_impl::owner::tx_lock_outputs(&mut *w, &slate, 0).unwrap();
 		}
 		if finalize_tx {
 			api_impl::owner::finalize_tx(&mut *w, &slate).unwrap();
diff --git a/controller/src/command.rs b/controller/src/command.rs
index 346db7e37..4c57c3c8f 100644
--- a/controller/src/command.rs
+++ b/controller/src/command.rs
@@ -300,7 +300,7 @@ pub fn send(
 			};
 			if adapter.supports_sync() {
 				slate = adapter.send_tx_sync(&args.dest, &slate)?;
-				api.tx_lock_outputs(&slate)?;
+				api.tx_lock_outputs(&slate, 0)?;
 				if args.method == "self" {
 					controller::foreign_single_use(wallet, |api| {
 						slate = api.receive_tx(&slate, Some(&args.dest), None)?;
@@ -314,7 +314,7 @@ pub fn send(
 				slate = api.finalize_tx(&slate)?;
 			} else {
 				adapter.send_tx_async(&args.dest, &slate)?;
-				api.tx_lock_outputs(&slate)?;
+				api.tx_lock_outputs(&slate, 0)?;
 			}
 			if adapter.supports_sync() {
 				let result = api.post_tx(&slate.tx, args.fluff);
@@ -536,7 +536,7 @@ pub fn process_invoice(
 			};
 			if adapter.supports_sync() {
 				slate = adapter.send_tx_sync(&args.dest, &slate)?;
-				api.tx_lock_outputs(&slate)?;
+				api.tx_lock_outputs(&slate, 0)?;
 				if args.method == "self" {
 					controller::foreign_single_use(wallet, |api| {
 						slate = api.finalize_invoice_tx(&slate)?;
@@ -545,7 +545,7 @@ pub fn process_invoice(
 				}
 			} else {
 				adapter.send_tx_async(&args.dest, &slate)?;
-				api.tx_lock_outputs(&slate)?;
+				api.tx_lock_outputs(&slate, 0)?;
 			}
 		}
 		Ok(())
diff --git a/controller/src/controller.rs b/controller/src/controller.rs
index 927781c16..73b2dc308 100644
--- a/controller/src/controller.rs
+++ b/controller/src/controller.rs
@@ -400,7 +400,7 @@ where
 					))?;
 				}
 			}
-			api.tx_lock_outputs(&slate)?;
+			api.tx_lock_outputs(&slate, 0)?;
 			if args.method != "file" {
 				slate = api.finalize_tx(&slate)?;
 			}
diff --git a/controller/tests/accounts.rs b/controller/tests/accounts.rs
index 1feb699dc..e773d9a18 100644
--- a/controller/tests/accounts.rs
+++ b/controller/tests/accounts.rs
@@ -191,7 +191,7 @@ fn accounts_test_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 		};
 		let mut slate = api.init_send_tx(args)?;
 		slate = client1.send_tx_slate_direct("wallet2", &slate)?;
-		api.tx_lock_outputs(&slate)?;
+		api.tx_lock_outputs(&slate, 0)?;
 		slate = api.finalize_tx(&slate)?;
 		api.post_tx(&slate.tx, false)?;
 		Ok(())
diff --git a/controller/tests/check.rs b/controller/tests/check.rs
index cf8d2a0ef..cd17ad942 100644
--- a/controller/tests/check.rs
+++ b/controller/tests/check.rs
@@ -192,7 +192,7 @@ fn check_repair_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 		let file_adapter = FileWalletCommAdapter::new();
 		let send_file = format!("{}/part_tx_1.tx", test_dir);
 		file_adapter.send_tx_async(&send_file, &mut slate)?;
-		api.tx_lock_outputs(&slate)?;
+		api.tx_lock_outputs(&slate, 0)?;
 		Ok(())
 	})?;
 
diff --git a/controller/tests/file.rs b/controller/tests/file.rs
index a41989bd3..0ac743814 100644
--- a/controller/tests/file.rs
+++ b/controller/tests/file.rs
@@ -121,7 +121,7 @@ fn file_exchange_test_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 		// output tx file
 		let file_adapter = FileWalletCommAdapter::new();
 		file_adapter.send_tx_async(&send_file, &mut slate)?;
-		api.tx_lock_outputs(&slate)?;
+		api.tx_lock_outputs(&slate, 0)?;
 		Ok(())
 	})?;
 
diff --git a/controller/tests/invoice.rs b/controller/tests/invoice.rs
index faf61253e..7d31e2d3e 100644
--- a/controller/tests/invoice.rs
+++ b/controller/tests/invoice.rs
@@ -124,7 +124,7 @@ fn invoice_tx_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 				..Default::default()
 			};
 			slate = api.process_invoice_tx(&slate, args)?;
-			api.tx_lock_outputs(&slate)?;
+			api.tx_lock_outputs(&slate, 0)?;
 			Ok(())
 		})?;
 
@@ -160,9 +160,6 @@ fn invoice_tx_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 			Ok(())
 		})?;
 
-		// let logging finish
-		thread::sleep(Duration::from_millis(200));
-
 		// Check transaction log for wallet 1, ensure only 1 entry
 		// exists
 		wallet::controller::owner_single_use(wallet1.clone(), |api| {
@@ -176,7 +173,44 @@ fn invoice_tx_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 			);
 			Ok(())
 		})?;
+
+		// Test self-sending
+		wallet::controller::owner_single_use(wallet1.clone(), |api| {
+			// Wallet 1 inititates an invoice transaction, requesting payment
+			let args = IssueInvoiceTxArgs {
+				amount: reward * 2,
+				..Default::default()
+			};
+			slate = api.issue_invoice_tx(args)?;
+			// Wallet 1 receives the invoice transaction
+			let args = InitTxArgs {
+				src_acct_name: None,
+				amount: slate.amount,
+				minimum_confirmations: 2,
+				max_outputs: 500,
+				num_change_outputs: 1,
+				selection_strategy_is_use_all: true,
+				..Default::default()
+			};
+			slate = api.process_invoice_tx(&slate, args)?;
+			api.tx_lock_outputs(&slate, 0)?;
+			Ok(())
+		})?;
+
+		// wallet 1 finalizes and posts
+		wallet::controller::foreign_single_use(wallet1.clone(), |api| {
+			// Wallet 2 receives the invoice transaction
+			slate = api.finalize_invoice_tx(&slate)?;
+			Ok(())
+		})?;
+
+		let _ = test_framework::award_blocks_to_wallet(&chain, wallet1.clone(), 3, false);
+		//bh += 3;
+
+		// let logging finish
+		thread::sleep(Duration::from_millis(200));
 	}
+
 	teardown(test_dir);
 	Ok(())
 }
diff --git a/controller/tests/repost.rs b/controller/tests/repost.rs
index 0df02e9a6..856dc472a 100644
--- a/controller/tests/repost.rs
+++ b/controller/tests/repost.rs
@@ -116,7 +116,7 @@ fn file_repost_test_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 		// output tx file
 		let file_adapter = FileWalletCommAdapter::new();
 		file_adapter.send_tx_async(&send_file, &mut slate)?;
-		api.tx_lock_outputs(&slate)?;
+		api.tx_lock_outputs(&slate, 0)?;
 		Ok(())
 	})?;
 
@@ -211,7 +211,7 @@ fn file_repost_test_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 		};
 		let slate_i = sender_api.init_send_tx(args)?;
 		slate = client1.send_tx_slate_direct("wallet2", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&mut slate)?;
 		Ok(())
 	})?;
diff --git a/controller/tests/restore.rs b/controller/tests/restore.rs
index c2cc82414..b4261a540 100644
--- a/controller/tests/restore.rs
+++ b/controller/tests/restore.rs
@@ -247,7 +247,7 @@ fn setup_restore(test_dir: &str) -> Result<(), libwallet::Error> {
 		};
 		let slate_i = sender_api.init_send_tx(args)?;
 		slate = client1.send_tx_slate_direct("wallet2", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&slate)?;
 		sender_api.post_tx(&slate.tx, false)?;
 		Ok(())
@@ -270,7 +270,7 @@ fn setup_restore(test_dir: &str) -> Result<(), libwallet::Error> {
 		};
 		let slate_i = sender_api.init_send_tx(args)?;
 		slate = client1.send_tx_slate_direct("wallet3", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&slate)?;
 		sender_api.post_tx(&slate.tx, false)?;
 		Ok(())
@@ -293,7 +293,7 @@ fn setup_restore(test_dir: &str) -> Result<(), libwallet::Error> {
 		};
 		let slate_i = sender_api.init_send_tx(args)?;
 		slate = client3.send_tx_slate_direct("wallet2", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&slate)?;
 		sender_api.post_tx(&slate.tx, false)?;
 		Ok(())
@@ -322,7 +322,7 @@ fn setup_restore(test_dir: &str) -> Result<(), libwallet::Error> {
 		};
 		let slate_i = sender_api.init_send_tx(args)?;
 		slate = client3.send_tx_slate_direct("wallet2", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&slate)?;
 		sender_api.post_tx(&slate.tx, false)?;
 		Ok(())
diff --git a/controller/tests/self_send.rs b/controller/tests/self_send.rs
index 20ab2280b..f7efd2f25 100644
--- a/controller/tests/self_send.rs
+++ b/controller/tests/self_send.rs
@@ -97,7 +97,7 @@ fn self_send_test_impl(test_dir: &str) -> Result<(), libwallet::Error> {
 			..Default::default()
 		};
 		let mut slate = api.init_send_tx(args)?;
-		api.tx_lock_outputs(&slate)?;
+		api.tx_lock_outputs(&slate, 0)?;
 		// Send directly to self
 		wallet::controller::foreign_single_use(wallet1.clone(), |api| {
 			slate = api.receive_tx(&slate, Some("listener"), None)?;
diff --git a/controller/tests/transaction.rs b/controller/tests/transaction.rs
index bd121e2f1..336a8577f 100644
--- a/controller/tests/transaction.rs
+++ b/controller/tests/transaction.rs
@@ -115,7 +115,7 @@ fn basic_transaction_api(test_dir: &str) -> Result<(), libwallet::Error> {
 		assert_eq!(0, slate.lock_height);
 
 		slate = client1.send_tx_slate_direct("wallet2", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&slate)?;
 
 		// Check we have a single kernel and that it is a Plain kernel (no lock_height).
@@ -297,7 +297,7 @@ fn basic_transaction_api(test_dir: &str) -> Result<(), libwallet::Error> {
 		};
 		let slate_i = sender_api.init_send_tx(args)?;
 		slate = client1.send_tx_slate_direct("wallet2", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&slate)?;
 		Ok(())
 	})?;
@@ -397,7 +397,7 @@ fn tx_rollback(test_dir: &str) -> Result<(), libwallet::Error> {
 
 		let slate_i = sender_api.init_send_tx(args)?;
 		slate = client1.send_tx_slate_direct("wallet2", &slate_i)?;
-		sender_api.tx_lock_outputs(&slate)?;
+		sender_api.tx_lock_outputs(&slate, 0)?;
 		slate = sender_api.finalize_tx(&slate)?;
 		Ok(())
 	})?;
diff --git a/impls/src/backends/lmdb.rs b/impls/src/backends/lmdb.rs
index 3fd9df74c..6d274dd51 100644
--- a/impls/src/backends/lmdb.rs
+++ b/impls/src/backends/lmdb.rs
@@ -250,8 +250,16 @@ where
 		Box::new(self.db.iter(&[TX_LOG_ENTRY_PREFIX]).unwrap().map(|o| o.1))
 	}
 
-	fn get_private_context(&mut self, slate_id: &[u8]) -> Result<Context, Error> {
-		let ctx_key = to_key(PRIVATE_TX_CONTEXT_PREFIX, &mut slate_id.to_vec());
+	fn get_private_context(
+		&mut self,
+		slate_id: &[u8],
+		participant_id: usize,
+	) -> Result<Context, Error> {
+		let ctx_key = to_key_u64(
+			PRIVATE_TX_CONTEXT_PREFIX,
+			&mut slate_id.to_vec(),
+			participant_id as u64,
+		);
 		let (blind_xor_key, nonce_xor_key) = private_ctx_xor_keys(self.keychain(), slate_id)?;
 
 		let mut ctx: Context = option_to_not_found(
@@ -538,8 +546,17 @@ where
 		self.save(out.clone())
 	}
 
-	fn save_private_context(&mut self, slate_id: &[u8], ctx: &Context) -> Result<(), Error> {
-		let ctx_key = to_key(PRIVATE_TX_CONTEXT_PREFIX, &mut slate_id.to_vec());
+	fn save_private_context(
+		&mut self,
+		slate_id: &[u8],
+		participant_id: usize,
+		ctx: &Context,
+	) -> Result<(), Error> {
+		let ctx_key = to_key_u64(
+			PRIVATE_TX_CONTEXT_PREFIX,
+			&mut slate_id.to_vec(),
+			participant_id as u64,
+		);
 		let (blind_xor_key, nonce_xor_key) = private_ctx_xor_keys(self.keychain(), slate_id)?;
 
 		let mut s_ctx = ctx.clone();
@@ -556,8 +573,16 @@ where
 		Ok(())
 	}
 
-	fn delete_private_context(&mut self, slate_id: &[u8]) -> Result<(), Error> {
-		let ctx_key = to_key(PRIVATE_TX_CONTEXT_PREFIX, &mut slate_id.to_vec());
+	fn delete_private_context(
+		&mut self,
+		slate_id: &[u8],
+		participant_id: usize,
+	) -> Result<(), Error> {
+		let ctx_key = to_key_u64(
+			PRIVATE_TX_CONTEXT_PREFIX,
+			&mut slate_id.to_vec(),
+			participant_id as u64,
+		);
 		self.db
 			.borrow()
 			.as_ref()
diff --git a/impls/src/test_framework/mod.rs b/impls/src/test_framework/mod.rs
index 3ad0d2ffc..9aac68292 100644
--- a/impls/src/test_framework/mod.rs
+++ b/impls/src/test_framework/mod.rs
@@ -207,7 +207,7 @@ where
 		};
 		let slate_i = owner::init_send_tx(&mut *w, args, test_mode)?;
 		let slate = client.send_tx_slate_direct(dest, &slate_i)?;
-		owner::tx_lock_outputs(&mut *w, &slate)?;
+		owner::tx_lock_outputs(&mut *w, &slate, 0)?;
 		let slate = owner::finalize_tx(&mut *w, &slate)?;
 		w.close()?;
 		slate
diff --git a/libwallet/src/api_impl/foreign.rs b/libwallet/src/api_impl/foreign.rs
index 713d4b2a2..975d14b7e 100644
--- a/libwallet/src/api_impl/foreign.rs
+++ b/libwallet/src/api_impl/foreign.rs
@@ -118,13 +118,13 @@ where
 	K: Keychain,
 {
 	let mut sl = slate.clone();
-	let context = w.get_private_context(sl.id.as_bytes())?;
+	let context = w.get_private_context(sl.id.as_bytes(), 1)?;
 	tx::complete_tx(&mut *w, &mut sl, 1, &context)?;
 	tx::update_stored_tx(&mut *w, &mut sl, true)?;
 	tx::update_message(&mut *w, &mut sl)?;
 	{
 		let mut batch = w.batch()?;
-		batch.delete_private_context(sl.id.as_bytes())?;
+		batch.delete_private_context(sl.id.as_bytes(), 1)?;
 		batch.commit()?;
 	}
 	Ok(sl)
diff --git a/libwallet/src/api_impl/owner.rs b/libwallet/src/api_impl/owner.rs
index 1f1b94f7e..51f03293a 100644
--- a/libwallet/src/api_impl/owner.rs
+++ b/libwallet/src/api_impl/owner.rs
@@ -201,7 +201,7 @@ where
 	// recieve the transaction back
 	{
 		let mut batch = w.batch()?;
-		batch.save_private_context(slate.id.as_bytes(), &context)?;
+		batch.save_private_context(slate.id.as_bytes(), 0, &context)?;
 		batch.commit()?;
 	}
 	if let Some(v) = args.target_slate_version {
@@ -255,7 +255,7 @@ where
 	// recieve the transaction back
 	{
 		let mut batch = w.batch()?;
-		batch.save_private_context(slate.id.as_bytes(), &context)?;
+		batch.save_private_context(slate.id.as_bytes(), 1, &context)?;
 		batch.commit()?;
 	}
 
@@ -329,7 +329,7 @@ where
 	// recieve the transaction back
 	{
 		let mut batch = w.batch()?;
-		batch.save_private_context(slate.id.as_bytes(), &context)?;
+		batch.save_private_context(slate.id.as_bytes(), 0, &context)?;
 		batch.commit()?;
 	}
 
@@ -337,13 +337,17 @@ where
 }
 
 /// Lock sender outputs
-pub fn tx_lock_outputs<T: ?Sized, C, K>(w: &mut T, slate: &Slate) -> Result<(), Error>
+pub fn tx_lock_outputs<T: ?Sized, C, K>(
+	w: &mut T,
+	slate: &Slate,
+	participant_id: usize,
+) -> Result<(), Error>
 where
 	T: WalletBackend<C, K>,
 	C: NodeClient,
 	K: Keychain,
 {
-	let context = w.get_private_context(slate.id.as_bytes())?;
+	let context = w.get_private_context(slate.id.as_bytes(), participant_id)?;
 	selection::lock_tx_context(&mut *w, slate, &context)
 }
 
@@ -355,13 +359,13 @@ where
 	K: Keychain,
 {
 	let mut sl = slate.clone();
-	let context = w.get_private_context(sl.id.as_bytes())?;
+	let context = w.get_private_context(sl.id.as_bytes(), 0)?;
 	tx::complete_tx(&mut *w, &mut sl, 0, &context)?;
 	tx::update_stored_tx(&mut *w, &mut sl, false)?;
 	tx::update_message(&mut *w, &mut sl)?;
 	{
 		let mut batch = w.batch()?;
-		batch.delete_private_context(sl.id.as_bytes())?;
+		batch.delete_private_context(sl.id.as_bytes(), 0)?;
 		batch.commit()?;
 	}
 	Ok(sl)
diff --git a/libwallet/src/internal/selection.rs b/libwallet/src/internal/selection.rs
index 927a04d75..8bb1c1f61 100644
--- a/libwallet/src/internal/selection.rs
+++ b/libwallet/src/internal/selection.rs
@@ -66,6 +66,7 @@ where
 		blinding.secret_key(&keychain.secp()).unwrap(),
 		&parent_key_id,
 		use_test_nonce,
+		0,
 	);
 
 	context.fee = fee;
@@ -199,6 +200,7 @@ where
 			.unwrap(),
 		&parent_key_id,
 		use_test_rng,
+		1,
 	);
 
 	context.add_output(&key_id, &None, amount);
diff --git a/libwallet/src/types.rs b/libwallet/src/types.rs
index c79a28b65..3c9fd3c36 100644
--- a/libwallet/src/types.rs
+++ b/libwallet/src/types.rs
@@ -95,7 +95,11 @@ where
 	fn get_tx_log_entry(&self, uuid: &Uuid) -> Result<Option<TxLogEntry>, Error>;
 
 	/// Retrieves the private context associated with a given slate id
-	fn get_private_context(&mut self, slate_id: &[u8]) -> Result<Context, Error>;
+	fn get_private_context(
+		&mut self,
+		slate_id: &[u8],
+		participant_id: usize,
+	) -> Result<Context, Error>;
 
 	/// Iterate over all output data stored by the backend
 	fn tx_log_iter<'a>(&'a self) -> Box<dyn Iterator<Item = TxLogEntry> + 'a>;
@@ -181,10 +185,19 @@ where
 	fn lock_output(&mut self, out: &mut OutputData) -> Result<(), Error>;
 
 	/// Saves the private context associated with a slate id
-	fn save_private_context(&mut self, slate_id: &[u8], ctx: &Context) -> Result<(), Error>;
+	fn save_private_context(
+		&mut self,
+		slate_id: &[u8],
+		participant_id: usize,
+		ctx: &Context,
+	) -> Result<(), Error>;
 
 	/// Delete the private context associated with the slate id
-	fn delete_private_context(&mut self, slate_id: &[u8]) -> Result<(), Error>;
+	fn delete_private_context(
+		&mut self,
+		slate_id: &[u8],
+		participant_id: usize,
+	) -> Result<(), Error>;
 
 	/// Write the wallet data to backend file
 	fn commit(&self) -> Result<(), Error>;
@@ -391,6 +404,8 @@ pub struct Context {
 	pub input_ids: Vec<(Identifier, Option<u64>, u64)>,
 	/// store the calculated fee
 	pub fee: u64,
+	/// keep track of the participant id
+	pub participant_id: usize,
 }
 
 impl Context {
@@ -400,6 +415,7 @@ impl Context {
 		sec_key: SecretKey,
 		parent_key_id: &Identifier,
 		use_test_rng: bool,
+		participant_id: usize,
 	) -> Context {
 		let sec_nonce = match use_test_rng {
 			false => aggsig::create_secnonce(secp).unwrap(),
@@ -412,6 +428,7 @@ impl Context {
 			input_ids: vec![],
 			output_ids: vec![],
 			fee: 0,
+			participant_id: participant_id,
 		}
 	}
 }
diff --git a/libwallet/tests/libwallet.rs b/libwallet/tests/libwallet.rs
index 76fea7835..b3bcfb349 100644
--- a/libwallet/tests/libwallet.rs
+++ b/libwallet/tests/libwallet.rs
@@ -71,7 +71,7 @@ fn aggsig_sender_receiver_interaction() {
 
 		let blind = blinding_factor.secret_key(&keychain.secp()).unwrap();
 
-		s_cx = Context::new(&keychain.secp(), blind, &parent, false);
+		s_cx = Context::new(&keychain.secp(), blind, &parent, false, 0);
 		s_cx.get_public_keys(&keychain.secp())
 	};
 
@@ -85,7 +85,7 @@ fn aggsig_sender_receiver_interaction() {
 		// let blind = blind_sum.secret_key(&keychain.secp())?;
 		let blind = keychain.derive_key(0, &key_id).unwrap();
 
-		rx_cx = Context::new(&keychain.secp(), blind, &parent, false);
+		rx_cx = Context::new(&keychain.secp(), blind, &parent, false, 1);
 		let (pub_excess, pub_nonce) = rx_cx.get_public_keys(&keychain.secp());
 		rx_cx.add_output(&key_id, &None, 0);
 
@@ -289,7 +289,7 @@ fn aggsig_sender_receiver_interaction_offset() {
 
 		let blind = blinding_factor.secret_key(&keychain.secp()).unwrap();
 
-		s_cx = Context::new(&keychain.secp(), blind, &parent, false);
+		s_cx = Context::new(&keychain.secp(), blind, &parent, false, 0);
 		s_cx.get_public_keys(&keychain.secp())
 	};
 
@@ -302,7 +302,7 @@ fn aggsig_sender_receiver_interaction_offset() {
 
 		let blind = keychain.derive_key(0, &key_id).unwrap();
 
-		rx_cx = Context::new(&keychain.secp(), blind, &parent, false);
+		rx_cx = Context::new(&keychain.secp(), blind, &parent, false, 1);
 		let (pub_excess, pub_nonce) = rx_cx.get_public_keys(&keychain.secp());
 		rx_cx.add_output(&key_id, &None, 0);