refactor transaction sign scheme (#1621)

bridges/relays/lib-substrate-relay/src/conversion_rate_update.rs

@@ -19,8 +19,8 @@
 use crate::{messages_lane::SubstrateMessageLane, TransactionParams};
 
 use relay_substrate_client::{
-	transaction_stall_timeout, AccountIdOf, AccountKeyPairOf, CallOf, Chain, Client, SignParam,
-	TransactionEra, TransactionSignScheme, UnsignedTransaction,
+	transaction_stall_timeout, AccountIdOf, AccountKeyPairOf, CallOf, Chain, ChainWithTransactions,
+	Client, SignParam, TransactionEra, UnsignedTransaction,
 };
 use relay_utils::metrics::F64SharedRef;
 use sp_core::Pair;
@@ -119,17 +119,17 @@ macro_rules! generate_mocked_update_conversion_rate_call_builder {
 ///
 /// The loop is maintaining the Left -> Right conversion rate, used as `RightTokens = LeftTokens *
 /// Rate`.
-pub fn run_conversion_rate_update_loop<Lane, Sign>(
+pub fn run_conversion_rate_update_loop<Lane>(
 	client: Client<Lane::SourceChain>,
-	transaction_params: TransactionParams<AccountKeyPairOf<Sign>>,
+	transaction_params: TransactionParams<AccountKeyPairOf<Lane::SourceChain>>,
 	left_to_right_stored_conversion_rate: F64SharedRef,
 	left_to_base_conversion_rate: F64SharedRef,
 	right_to_base_conversion_rate: F64SharedRef,
 	max_difference_ratio: f64,
 ) where
 	Lane: SubstrateMessageLane,
-	Sign: TransactionSignScheme<Chain = Lane::SourceChain>,
-	AccountIdOf<Lane::SourceChain>: From<<AccountKeyPairOf<Sign> as Pair>::Public>,
+	Lane::SourceChain: ChainWithTransactions,
+	AccountIdOf<Lane::SourceChain>: From<<AccountKeyPairOf<Lane::SourceChain> as Pair>::Public>,
 {
 	let stall_timeout = transaction_stall_timeout(
 		transaction_params.mortality,
@@ -169,7 +169,7 @@ pub fn run_conversion_rate_update_loop<Lane, Sign>(
 					new_conversion_rate,
 				);
 
-				let result = update_target_to_source_conversion_rate::<Lane, Sign>(
+				let result = update_target_to_source_conversion_rate::<Lane>(
 					client.clone(),
 					transaction_params.clone(),
 					new_conversion_rate,
@@ -253,15 +253,15 @@ async fn maybe_select_new_conversion_rate(
 }
 
 /// Update Target -> Source tokens conversion rate, stored in the Source runtime storage.
-pub async fn update_target_to_source_conversion_rate<Lane, Sign>(
+pub async fn update_target_to_source_conversion_rate<Lane>(
 	client: Client<Lane::SourceChain>,
-	transaction_params: TransactionParams<AccountKeyPairOf<Sign>>,
+	transaction_params: TransactionParams<AccountKeyPairOf<Lane::SourceChain>>,
 	updated_rate: f64,
 ) -> anyhow::Result<()>
 where
 	Lane: SubstrateMessageLane,
-	Sign: TransactionSignScheme<Chain = Lane::SourceChain>,
-	AccountIdOf<Lane::SourceChain>: From<<AccountKeyPairOf<Sign> as Pair>::Public>,
+	Lane::SourceChain: ChainWithTransactions,
+	AccountIdOf<Lane::SourceChain>: From<<AccountKeyPairOf<Lane::SourceChain> as Pair>::Public>,
 {
 	let genesis_hash = *client.genesis_hash();
 	let signer_id = transaction_params.signer.public().into();
@@ -273,7 +273,7 @@ where
 	client
 		.submit_signed_extrinsic(
 			signer_id,
-			SignParam::<Sign> {
+			SignParam::<Lane::SourceChain> {
 				spec_version,
 				transaction_version,
 				genesis_hash,

bridges/relays/lib-substrate-relay/src/finality/guards.rs

@@ -19,19 +19,19 @@
 use crate::TransactionParams;
 
 use relay_substrate_client::{
-	AccountIdOf, AccountKeyPairOf, ChainWithBalances, TransactionSignScheme,
+	AccountIdOf, AccountKeyPairOf, ChainWithBalances, ChainWithTransactions,
 };
 use sp_core::Pair;
 
 /// Start finality relay guards.
-pub async fn start<C: ChainWithBalances, S: TransactionSignScheme<Chain = C>>(
+pub async fn start<C: ChainWithBalances + ChainWithTransactions>(
 	target_client: &relay_substrate_client::Client<C>,
-	transaction_params: &TransactionParams<S::AccountKeyPair>,
+	transaction_params: &TransactionParams<AccountKeyPairOf<C>>,
 	enable_version_guard: bool,
 	maximal_balance_decrease_per_day: C::Balance,
 ) -> relay_substrate_client::Result<()>
 where
-	AccountIdOf<C>: From<<AccountKeyPairOf<S> as Pair>::Public>,
+	AccountIdOf<C>: From<<AccountKeyPairOf<C> as Pair>::Public>,
 {
 	if enable_version_guard {
 		relay_substrate_client::guard::abort_on_spec_version_change(

bridges/relays/lib-substrate-relay/src/finality/initialize.rs

@@ -24,7 +24,7 @@
 use crate::{error::Error, finality::engine::Engine};
 
 use relay_substrate_client::{
-	Chain, Client, Error as SubstrateError, SignParam, TransactionSignScheme, UnsignedTransaction,
+	Chain, ChainWithTransactions, Client, Error as SubstrateError, SignParam, UnsignedTransaction,
 };
 use sp_runtime::traits::Header as HeaderT;
 
@@ -32,7 +32,7 @@ use sp_runtime::traits::Header as HeaderT;
 pub async fn initialize<
 	E: Engine<SourceChain>,
 	SourceChain: Chain,
-	TargetChain: Chain + TransactionSignScheme<Chain = TargetChain>,
+	TargetChain: ChainWithTransactions,
 	F,
 >(
 	source_client: Client<SourceChain>,
@@ -80,7 +80,7 @@ pub async fn initialize<
 async fn do_initialize<
 	E: Engine<SourceChain>,
 	SourceChain: Chain,
-	TargetChain: Chain + TransactionSignScheme<Chain = TargetChain>,
+	TargetChain: ChainWithTransactions,
 	F,
 >(
 	source_client: Client<SourceChain>,

bridges/relays/lib-substrate-relay/src/finality/mod.rs

@@ -31,8 +31,8 @@ use bp_header_chain::justification::GrandpaJustification;
 use finality_relay::FinalitySyncPipeline;
 use pallet_bridge_grandpa::{Call as BridgeGrandpaCall, Config as BridgeGrandpaConfig};
 use relay_substrate_client::{
-	transaction_stall_timeout, AccountIdOf, AccountKeyPairOf, BlockNumberOf, CallOf, Chain, Client,
-	HashOf, HeaderOf, SyncHeader, TransactionSignScheme,
+	transaction_stall_timeout, AccountIdOf, AccountKeyPairOf, BlockNumberOf, CallOf, Chain,
+	ChainWithTransactions, Client, HashOf, HeaderOf, SyncHeader,
 };
 use relay_utils::metrics::MetricsParams;
 use sp_core::Pair;
@@ -56,19 +56,17 @@ pub trait SubstrateFinalitySyncPipeline: 'static + Clone + Debug + Send + Sync {
 	/// Headers of this chain are submitted to the `TargetChain`.
 	type SourceChain: Chain;
 	/// Headers of the `SourceChain` are submitted to this chain.
-	type TargetChain: Chain;
+	type TargetChain: ChainWithTransactions;
 
 	/// Finality engine.
 	type FinalityEngine: Engine<Self::SourceChain>;
 	/// How submit finality proof call is built?
 	type SubmitFinalityProofCallBuilder: SubmitFinalityProofCallBuilder<Self>;
-	/// Scheme used to sign target chain transactions.
-	type TransactionSignScheme: TransactionSignScheme;
 
 	/// Add relay guards if required.
 	async fn start_relay_guards(
 		_target_client: &Client<Self::TargetChain>,
-		_transaction_params: &TransactionParams<AccountKeyPairOf<Self::TransactionSignScheme>>,
+		_transaction_params: &TransactionParams<AccountKeyPairOf<Self::TargetChain>>,
 		_enable_version_guard: bool,
 	) -> relay_substrate_client::Result<()> {
 		Ok(())
@@ -169,12 +167,11 @@ pub async fn run<P: SubstrateFinalitySyncPipeline>(
 	source_client: Client<P::SourceChain>,
 	target_client: Client<P::TargetChain>,
 	only_mandatory_headers: bool,
-	transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+	transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	metrics_params: MetricsParams,
 ) -> anyhow::Result<()>
 where
-	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TransactionSignScheme> as Pair>::Public>,
-	P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as Pair>::Public>,
 {
 	log::info!(
 		target: "bridge",

bridges/relays/lib-substrate-relay/src/finality/target.rs

@@ -28,7 +28,7 @@ use async_trait::async_trait;
 use finality_relay::TargetClient;
 use relay_substrate_client::{
 	AccountIdOf, AccountKeyPairOf, Chain, Client, Error, HeaderIdOf, HeaderOf, SignParam,
-	SyncHeader, TransactionEra, TransactionSignScheme, TransactionTracker, UnsignedTransaction,
+	SyncHeader, TransactionEra, TransactionTracker, UnsignedTransaction,
 };
 use relay_utils::relay_loop::Client as RelayClient;
 use sp_core::Pair;
@@ -36,14 +36,14 @@ use sp_core::Pair;
 /// Substrate client as Substrate finality target.
 pub struct SubstrateFinalityTarget<P: SubstrateFinalitySyncPipeline> {
 	client: Client<P::TargetChain>,
-	transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+	transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 }
 
 impl<P: SubstrateFinalitySyncPipeline> SubstrateFinalityTarget<P> {
 	/// Create new Substrate headers target.
 	pub fn new(
 		client: Client<P::TargetChain>,
-		transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+		transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	) -> Self {
 		SubstrateFinalityTarget { client, transaction_params }
 	}
@@ -86,8 +86,7 @@ impl<P: SubstrateFinalitySyncPipeline> RelayClient for SubstrateFinalityTarget<P
 impl<P: SubstrateFinalitySyncPipeline> TargetClient<FinalitySyncPipelineAdapter<P>>
 	for SubstrateFinalityTarget<P>
 where
-	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TransactionSignScheme> as Pair>::Public>,
-	P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as Pair>::Public>,
 {
 	type TransactionTracker = TransactionTracker<P::TargetChain, Client<P::TargetChain>>;
 
@@ -120,7 +119,7 @@ where
 		self.client
 			.submit_and_watch_signed_extrinsic(
 				self.transaction_params.signer.public().into(),
-				SignParam::<P::TransactionSignScheme> {
+				SignParam::<P::TargetChain> {
 					spec_version,
 					transaction_version,
 					genesis_hash,

bridges/relays/lib-substrate-relay/src/messages_lane.rs

@@ -37,7 +37,7 @@ use messages_relay::{message_lane::MessageLane, relay_strategy::RelayStrategy};
 use pallet_bridge_messages::{Call as BridgeMessagesCall, Config as BridgeMessagesConfig};
 use relay_substrate_client::{
 	transaction_stall_timeout, AccountKeyPairOf, BalanceOf, BlockNumberOf, CallOf, Chain,
-	ChainWithMessages, Client, HashOf, TransactionSignScheme,
+	ChainWithMessages, ChainWithTransactions, Client, HashOf,
 };
 use relay_utils::{metrics::MetricsParams, STALL_TIMEOUT};
 use sp_core::Pair;
@@ -77,14 +77,9 @@ pub trait SubstrateMessageLane: 'static + Clone + Debug + Send + Sync {
 	const AT_TARGET_TRANSACTION_PAYMENT_PALLET_NAME: Option<&'static str>;
 
 	/// Messages of this chain are relayed to the `TargetChain`.
-	type SourceChain: ChainWithMessages;
+	type SourceChain: ChainWithMessages + ChainWithTransactions;
 	/// Messages from the `SourceChain` are dispatched on this chain.
-	type TargetChain: ChainWithMessages;
-
-	/// Scheme used to sign source chain transactions.
-	type SourceTransactionSignScheme: TransactionSignScheme;
-	/// Scheme used to sign target chain transactions.
-	type TargetTransactionSignScheme: TransactionSignScheme;
+	type TargetChain: ChainWithMessages + ChainWithTransactions;
 
 	/// How receive messages proof call is built?
 	type ReceiveMessagesProofCallBuilder: ReceiveMessagesProofCallBuilder<Self>;
@@ -128,13 +123,11 @@ pub struct MessagesRelayParams<P: SubstrateMessageLane> {
 	/// Messages source client.
 	pub source_client: Client<P::SourceChain>,
 	/// Source transaction params.
-	pub source_transaction_params:
-		TransactionParams<AccountKeyPairOf<P::SourceTransactionSignScheme>>,
+	pub source_transaction_params: TransactionParams<AccountKeyPairOf<P::SourceChain>>,
 	/// Messages target client.
 	pub target_client: Client<P::TargetChain>,
 	/// Target transaction params.
-	pub target_transaction_params:
-		TransactionParams<AccountKeyPairOf<P::TargetTransactionSignScheme>>,
+	pub target_transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	/// Optional on-demand source to target headers relay.
 	pub source_to_target_headers_relay:
 		Option<Arc<dyn OnDemandRelay<BlockNumberOf<P::SourceChain>>>>,
@@ -154,13 +147,9 @@ pub struct MessagesRelayParams<P: SubstrateMessageLane> {
 /// Run Substrate-to-Substrate messages sync loop.
 pub async fn run<P: SubstrateMessageLane>(params: MessagesRelayParams<P>) -> anyhow::Result<()>
 where
-	AccountIdOf<P::SourceChain>:
-		From<<AccountKeyPairOf<P::SourceTransactionSignScheme> as Pair>::Public>,
-	AccountIdOf<P::TargetChain>:
-		From<<AccountKeyPairOf<P::TargetTransactionSignScheme> as Pair>::Public>,
+	AccountIdOf<P::SourceChain>: From<<AccountKeyPairOf<P::SourceChain> as Pair>::Public>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as Pair>::Public>,
 	BalanceOf<P::SourceChain>: TryFrom<BalanceOf<P::TargetChain>>,
-	P::SourceTransactionSignScheme: TransactionSignScheme<Chain = P::SourceChain>,
-	P::TargetTransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
 {
 	let source_client = params.source_client;
 	let target_client = params.target_client;

bridges/relays/lib-substrate-relay/src/messages_source.rs

@@ -49,9 +49,9 @@ use messages_relay::{
 };
 use num_traits::{Bounded, Zero};
 use relay_substrate_client::{
-	AccountIdOf, AccountKeyPairOf, BalanceOf, BlockNumberOf, Chain, ChainWithMessages, Client,
-	Error as SubstrateError, HashOf, HeaderIdOf, IndexOf, SignParam, TransactionEra,
-	TransactionSignScheme, TransactionTracker, UnsignedTransaction,
+	AccountIdOf, AccountKeyPairOf, BalanceOf, BlockNumberOf, Chain, ChainWithMessages,
+	ChainWithTransactions, Client, Error as SubstrateError, HashOf, HeaderIdOf, IndexOf, SignParam,
+	TransactionEra, TransactionTracker, UnsignedTransaction,
 };
 use relay_utils::{relay_loop::Client as RelayClient, HeaderId};
 use sp_core::{Bytes, Pair};
@@ -69,7 +69,7 @@ pub struct SubstrateMessagesSource<P: SubstrateMessageLane> {
 	source_client: Client<P::SourceChain>,
 	target_client: Client<P::TargetChain>,
 	lane_id: LaneId,
-	transaction_params: TransactionParams<AccountKeyPairOf<P::SourceTransactionSignScheme>>,
+	transaction_params: TransactionParams<AccountKeyPairOf<P::SourceChain>>,
 	target_to_source_headers_relay: Option<Arc<dyn OnDemandRelay<BlockNumberOf<P::TargetChain>>>>,
 }
 
@@ -79,7 +79,7 @@ impl<P: SubstrateMessageLane> SubstrateMessagesSource<P> {
 		source_client: Client<P::SourceChain>,
 		target_client: Client<P::TargetChain>,
 		lane_id: LaneId,
-		transaction_params: TransactionParams<AccountKeyPairOf<P::SourceTransactionSignScheme>>,
+		transaction_params: TransactionParams<AccountKeyPairOf<P::SourceChain>>,
 		target_to_source_headers_relay: Option<
 			Arc<dyn OnDemandRelay<BlockNumberOf<P::TargetChain>>>,
 		>,
@@ -140,9 +140,7 @@ impl<P: SubstrateMessageLane> RelayClient for SubstrateMessagesSource<P> {
 #[async_trait]
 impl<P: SubstrateMessageLane> SourceClient<MessageLaneAdapter<P>> for SubstrateMessagesSource<P>
 where
-	AccountIdOf<P::SourceChain>:
-		From<<AccountKeyPairOf<P::SourceTransactionSignScheme> as Pair>::Public>,
-	P::SourceTransactionSignScheme: TransactionSignScheme<Chain = P::SourceChain>,
+	AccountIdOf<P::SourceChain>: From<<AccountKeyPairOf<P::SourceChain> as Pair>::Public>,
 {
 	type TransactionTracker = TransactionTracker<P::SourceChain, Client<P::SourceChain>>;
 
@@ -348,7 +346,7 @@ where
 		self.source_client
 			.submit_and_watch_signed_extrinsic(
 				self.transaction_params.signer.public().into(),
-				SignParam::<P::SourceTransactionSignScheme> {
+				SignParam::<P::SourceChain> {
 					spec_version,
 					transaction_version,
 					genesis_hash,
@@ -381,8 +379,8 @@ where
 			Err(_) => return BalanceOf::<P::SourceChain>::max_value(),
 		};
 		async {
-			let dummy_tx = P::SourceTransactionSignScheme::sign_transaction(
-				SignParam::<P::SourceTransactionSignScheme> {
+			let dummy_tx = P::SourceChain::sign_transaction(
+				SignParam::<P::SourceChain> {
 					spec_version: runtime_version.spec_version,
 					transaction_version: runtime_version.transaction_version,
 					genesis_hash: *self.source_client.genesis_hash(),
@@ -429,15 +427,12 @@ where
 
 /// Make messages delivery proof transaction from given proof.
 fn make_messages_delivery_proof_transaction<P: SubstrateMessageLane>(
-	source_transaction_params: &TransactionParams<AccountKeyPairOf<P::SourceTransactionSignScheme>>,
+	source_transaction_params: &TransactionParams<AccountKeyPairOf<P::SourceChain>>,
 	source_best_block_id: HeaderIdOf<P::SourceChain>,
 	transaction_nonce: IndexOf<P::SourceChain>,
 	proof: SubstrateMessagesDeliveryProof<P::TargetChain>,
 	trace_call: bool,
-) -> Result<UnsignedTransaction<P::SourceChain>, SubstrateError>
-where
-	P::SourceTransactionSignScheme: TransactionSignScheme<Chain = P::SourceChain>,
-{
+) -> Result<UnsignedTransaction<P::SourceChain>, SubstrateError> {
 	let call =
 		P::ReceiveMessagesDeliveryProofCallBuilder::build_receive_messages_delivery_proof_call(
 			proof, trace_call,

bridges/relays/lib-substrate-relay/src/messages_target.rs

@@ -43,9 +43,9 @@ use messages_relay::{
 };
 use num_traits::{Bounded, Zero};
 use relay_substrate_client::{
-	AccountIdOf, AccountKeyPairOf, BalanceOf, BlockNumberOf, Chain, ChainWithMessages, Client,
-	Error as SubstrateError, HashOf, HeaderIdOf, IndexOf, SignParam, TransactionEra,
-	TransactionSignScheme, TransactionTracker, UnsignedTransaction, WeightToFeeOf,
+	AccountIdOf, AccountKeyPairOf, BalanceOf, BlockNumberOf, Chain, ChainWithMessages,
+	ChainWithTransactions, Client, Error as SubstrateError, HashOf, HeaderIdOf, IndexOf, SignParam,
+	TransactionEra, TransactionTracker, UnsignedTransaction, WeightToFeeOf,
 };
 use relay_utils::{relay_loop::Client as RelayClient, HeaderId};
 use sp_core::{Bytes, Pair};
@@ -62,7 +62,7 @@ pub struct SubstrateMessagesTarget<P: SubstrateMessageLane> {
 	source_client: Client<P::SourceChain>,
 	lane_id: LaneId,
 	relayer_id_at_source: AccountIdOf<P::SourceChain>,
-	transaction_params: TransactionParams<AccountKeyPairOf<P::TargetTransactionSignScheme>>,
+	transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	metric_values: StandaloneMessagesMetrics<P::SourceChain, P::TargetChain>,
 	source_to_target_headers_relay: Option<Arc<dyn OnDemandRelay<BlockNumberOf<P::SourceChain>>>>,
 }
@@ -74,7 +74,7 @@ impl<P: SubstrateMessageLane> SubstrateMessagesTarget<P> {
 		source_client: Client<P::SourceChain>,
 		lane_id: LaneId,
 		relayer_id_at_source: AccountIdOf<P::SourceChain>,
-		transaction_params: TransactionParams<AccountKeyPairOf<P::TargetTransactionSignScheme>>,
+		transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 		metric_values: StandaloneMessagesMetrics<P::SourceChain, P::TargetChain>,
 		source_to_target_headers_relay: Option<
 			Arc<dyn OnDemandRelay<BlockNumberOf<P::SourceChain>>>,
@@ -140,9 +140,7 @@ impl<P: SubstrateMessageLane> RelayClient for SubstrateMessagesTarget<P> {
 #[async_trait]
 impl<P: SubstrateMessageLane> TargetClient<MessageLaneAdapter<P>> for SubstrateMessagesTarget<P>
 where
-	AccountIdOf<P::TargetChain>:
-		From<<AccountKeyPairOf<P::TargetTransactionSignScheme> as Pair>::Public>,
-	P::TargetTransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as Pair>::Public>,
 	BalanceOf<P::SourceChain>: TryFrom<BalanceOf<P::TargetChain>>,
 {
 	type TransactionTracker = TransactionTracker<P::TargetChain, Client<P::TargetChain>>;
@@ -258,7 +256,7 @@ where
 			.target_client
 			.submit_and_watch_signed_extrinsic(
 				self.transaction_params.signer.public().into(),
-				SignParam::<P::TargetTransactionSignScheme> {
+				SignParam::<P::TargetChain> {
 					spec_version,
 					transaction_version,
 					genesis_hash,
@@ -305,7 +303,7 @@ where
 		let (spec_version, transaction_version) =
 			self.target_client.simple_runtime_version().await?;
 		// Prepare 'dummy' delivery transaction - we only care about its length and dispatch weight.
-		let delivery_tx = P::TargetTransactionSignScheme::sign_transaction(
+		let delivery_tx = P::TargetChain::sign_transaction(
 			SignParam {
 				spec_version,
 				transaction_version,
@@ -352,7 +350,7 @@ where
 			let (spec_version, transaction_version) =
 				self.target_client.simple_runtime_version().await?;
 			let larger_dispatch_weight = total_dispatch_weight.saturating_add(WEIGHT_DIFFERENCE);
-			let dummy_tx = P::TargetTransactionSignScheme::sign_transaction(
+			let dummy_tx = P::TargetChain::sign_transaction(
 				SignParam {
 					spec_version,
 					transaction_version,
@@ -425,17 +423,14 @@ where
 
 /// Make messages delivery transaction from given proof.
 fn make_messages_delivery_transaction<P: SubstrateMessageLane>(
-	target_transaction_params: &TransactionParams<AccountKeyPairOf<P::TargetTransactionSignScheme>>,
+	target_transaction_params: &TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	target_best_block_id: HeaderIdOf<P::TargetChain>,
 	transaction_nonce: IndexOf<P::TargetChain>,
 	relayer_id_at_source: AccountIdOf<P::SourceChain>,
 	nonces: RangeInclusive<MessageNonce>,
 	proof: SubstrateMessagesProof<P::SourceChain>,
 	trace_call: bool,
-) -> Result<UnsignedTransaction<P::TargetChain>, SubstrateError>
-where
-	P::TargetTransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
-{
+) -> Result<UnsignedTransaction<P::TargetChain>, SubstrateError> {
 	let messages_count = nonces.end() - nonces.start() + 1;
 	let dispatch_weight = proof.0;
 	let call = P::ReceiveMessagesProofCallBuilder::build_receive_messages_proof_call(

bridges/relays/lib-substrate-relay/src/on_demand/headers.rs

@@ -24,9 +24,7 @@ use num_traits::{One, Zero};
 use sp_runtime::traits::Header;
 
 use finality_relay::{FinalitySyncParams, TargetClient as FinalityTargetClient};
-use relay_substrate_client::{
-	AccountIdOf, AccountKeyPairOf, BlockNumberOf, Chain, Client, TransactionSignScheme,
-};
+use relay_substrate_client::{AccountIdOf, AccountKeyPairOf, BlockNumberOf, Chain, Client};
 use relay_utils::{
 	metrics::MetricsParams, relay_loop::Client as RelayClient, FailedClient, MaybeConnectionError,
 	STALL_TIMEOUT,
@@ -61,13 +59,12 @@ impl<SourceChain: Chain> OnDemandHeadersRelay<SourceChain> {
 	pub fn new<P: SubstrateFinalitySyncPipeline<SourceChain = SourceChain>>(
 		source_client: Client<P::SourceChain>,
 		target_client: Client<P::TargetChain>,
-		target_transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+		target_transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 		only_mandatory_headers: bool,
 	) -> Self
 	where
 		AccountIdOf<P::TargetChain>:
-			From<<AccountKeyPairOf<P::TransactionSignScheme> as sp_core::Pair>::Public>,
-		P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+			From<<AccountKeyPairOf<P::TargetChain> as sp_core::Pair>::Public>,
 	{
 		let required_header_number = Arc::new(Mutex::new(Zero::zero()));
 		let this = OnDemandHeadersRelay {
@@ -113,13 +110,11 @@ impl<SourceChain: Chain> OnDemandRelay<BlockNumberOf<SourceChain>>
 async fn background_task<P: SubstrateFinalitySyncPipeline>(
 	source_client: Client<P::SourceChain>,
 	target_client: Client<P::TargetChain>,
-	target_transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+	target_transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	only_mandatory_headers: bool,
 	required_header_number: RequiredHeaderNumberRef<P::SourceChain>,
 ) where
-	AccountIdOf<P::TargetChain>:
-		From<<AccountKeyPairOf<P::TransactionSignScheme> as sp_core::Pair>::Public>,
-	P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as sp_core::Pair>::Public>,
 {
 	let relay_task_name = on_demand_headers_relay_name::<P::SourceChain, P::TargetChain>();
 	let target_transactions_mortality = target_transaction_params.mortality;
@@ -389,9 +384,7 @@ async fn best_finalized_source_header_at_target<P: SubstrateFinalitySyncPipeline
 	relay_task_name: &str,
 ) -> Result<BlockNumberOf<P::SourceChain>, <SubstrateFinalityTarget<P> as RelayClient>::Error>
 where
-	AccountIdOf<P::TargetChain>:
-		From<<AccountKeyPairOf<P::TransactionSignScheme> as sp_core::Pair>::Public>,
-	P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as sp_core::Pair>::Public>,
 {
 	finality_target
 		.best_finalized_source_block_id()

bridges/relays/lib-substrate-relay/src/on_demand/parachains.rs

@@ -39,7 +39,6 @@ use pallet_bridge_parachains::{RelayBlockHash, RelayBlockHasher, RelayBlockNumbe
 use parachains_relay::parachains_loop::{AvailableHeader, ParachainSyncParams, TargetClient};
 use relay_substrate_client::{
 	AccountIdOf, AccountKeyPairOf, BlockNumberOf, Chain, Client, Error as SubstrateError, HashOf,
-	TransactionSignScheme,
 };
 use relay_utils::{
 	metrics::MetricsParams, relay_loop::Client as RelayClient, FailedClient, HeaderId,
@@ -68,7 +67,7 @@ impl<SourceParachain: Chain> OnDemandParachainsRelay<SourceParachain> {
 	pub fn new<P: SubstrateParachainsPipeline<SourceParachain = SourceParachain>>(
 		source_relay_client: Client<P::SourceRelayChain>,
 		target_client: Client<P::TargetChain>,
-		target_transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+		target_transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 		on_demand_source_relay_to_target_headers: Arc<
 			dyn OnDemandRelay<BlockNumberOf<P::SourceRelayChain>>,
 		>,
@@ -78,8 +77,7 @@ impl<SourceParachain: Chain> OnDemandParachainsRelay<SourceParachain> {
 		P::SourceRelayChain:
 			Chain<BlockNumber = RelayBlockNumber, Hash = RelayBlockHash, Hasher = RelayBlockHasher>,
 		AccountIdOf<P::TargetChain>:
-			From<<AccountKeyPairOf<P::TransactionSignScheme> as sp_core::Pair>::Public>,
-		P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+			From<<AccountKeyPairOf<P::TargetChain> as sp_core::Pair>::Public>,
 	{
 		let (required_header_number_sender, required_header_number_receiver) = unbounded();
 		let this = OnDemandParachainsRelay {
@@ -125,7 +123,7 @@ where
 async fn background_task<P: SubstrateParachainsPipeline>(
 	source_relay_client: Client<P::SourceRelayChain>,
 	target_client: Client<P::TargetChain>,
-	target_transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+	target_transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	on_demand_source_relay_to_target_headers: Arc<
 		dyn OnDemandRelay<BlockNumberOf<P::SourceRelayChain>>,
 	>,
@@ -134,9 +132,7 @@ async fn background_task<P: SubstrateParachainsPipeline>(
 	P::SourceParachain: Chain<Hash = ParaHash>,
 	P::SourceRelayChain:
 		Chain<BlockNumber = RelayBlockNumber, Hash = RelayBlockHash, Hasher = RelayBlockHasher>,
-	AccountIdOf<P::TargetChain>:
-		From<<AccountKeyPairOf<P::TransactionSignScheme> as sp_core::Pair>::Public>,
-	P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as sp_core::Pair>::Public>,
 {
 	let relay_task_name = on_demand_parachains_relay_name::<P::SourceParachain, P::TargetChain>();
 	let target_transactions_mortality = target_transaction_params.mortality;

bridges/relays/lib-substrate-relay/src/parachains/mod.rs

@@ -24,7 +24,7 @@ use pallet_bridge_parachains::{
 	RelayBlockHasher, RelayBlockNumber,
 };
 use parachains_relay::ParachainsPipeline;
-use relay_substrate_client::{CallOf, Chain, HeaderIdOf, RelayChain, TransactionSignScheme};
+use relay_substrate_client::{CallOf, Chain, ChainWithTransactions, HeaderIdOf, RelayChain};
 use std::{fmt::Debug, marker::PhantomData};
 
 pub mod source;
@@ -41,12 +41,10 @@ pub trait SubstrateParachainsPipeline: 'static + Clone + Debug + Send + Sync {
 	/// Relay chain that is storing headers of `Self::SourceParachain`.
 	type SourceRelayChain: RelayChain;
 	/// Target chain where `Self::SourceParachain` headers are submitted.
-	type TargetChain: Chain;
+	type TargetChain: ChainWithTransactions;
 
 	/// How submit parachains heads call is built?
 	type SubmitParachainHeadsCallBuilder: SubmitParachainHeadsCallBuilder<Self>;
-	/// Scheme used to sign target chain transactions.
-	type TransactionSignScheme: TransactionSignScheme;
 
 	/// Id of the `Self::SourceParachain`, used for registration in `Self::SourceRelayChain`.
 	const SOURCE_PARACHAIN_PARA_ID: u32;

bridges/relays/lib-substrate-relay/src/parachains/target.rs

@@ -33,8 +33,8 @@ use parachains_relay::{
 };
 use relay_substrate_client::{
 	AccountIdOf, AccountKeyPairOf, BlockNumberOf, Chain, Client, Error as SubstrateError, HashOf,
-	HeaderIdOf, HeaderOf, RelayChain, SignParam, TransactionEra, TransactionSignScheme,
-	TransactionTracker, UnsignedTransaction,
+	HeaderIdOf, HeaderOf, RelayChain, SignParam, TransactionEra, TransactionTracker,
+	UnsignedTransaction,
 };
 use relay_utils::{relay_loop::Client as RelayClient, HeaderId};
 use sp_core::{Bytes, Pair};
@@ -43,14 +43,14 @@ use sp_runtime::traits::Header as HeaderT;
 /// Substrate client as parachain heads source.
 pub struct ParachainsTarget<P: SubstrateParachainsPipeline> {
 	client: Client<P::TargetChain>,
-	transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+	transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 }
 
 impl<P: SubstrateParachainsPipeline> ParachainsTarget<P> {
 	/// Creates new parachains target client.
 	pub fn new(
 		client: Client<P::TargetChain>,
-		transaction_params: TransactionParams<AccountKeyPairOf<P::TransactionSignScheme>>,
+		transaction_params: TransactionParams<AccountKeyPairOf<P::TargetChain>>,
 	) -> Self {
 		ParachainsTarget { client, transaction_params }
 	}
@@ -83,8 +83,7 @@ impl<P: SubstrateParachainsPipeline> RelayClient for ParachainsTarget<P> {
 impl<P> TargetClient<ParachainsPipelineAdapter<P>> for ParachainsTarget<P>
 where
 	P: SubstrateParachainsPipeline,
-	P::TransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
-	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TransactionSignScheme> as Pair>::Public>,
+	AccountIdOf<P::TargetChain>: From<<AccountKeyPairOf<P::TargetChain> as Pair>::Public>,
 {
 	type TransactionTracker = TransactionTracker<P::TargetChain, Client<P::TargetChain>>;
 
@@ -186,7 +185,7 @@ where
 		self.client
 			.submit_and_watch_signed_extrinsic(
 				self.transaction_params.signer.public().into(),
-				SignParam::<P::TransactionSignScheme> {
+				SignParam::<P::TargetChain> {
 					spec_version,
 					transaction_version,
 					genesis_hash,