diff --git a/ethcore/src/engines/authority_round.rs b/ethcore/src/engines/authority_round.rs
index f28a06117..f632c9382 100644
--- a/ethcore/src/engines/authority_round.rs
+++ b/ethcore/src/engines/authority_round.rs
@@ -21,13 +21,15 @@ use std::sync::Weak;
 use std::time::{UNIX_EPOCH, Duration};
 use util::*;
 use ethkey::{verify_address, Signature};
-use rlp::{Rlp, UntrustedRlp, View, encode};
+use rlp::{UntrustedRlp, Rlp, View, encode};
 use account_provider::AccountProvider;
 use block::*;
 use spec::CommonParams;
 use engines::Engine;
 use header::Header;
 use error::{Error, BlockError};
+use blockchain::extras::BlockDetails;
+use views::HeaderView;
 use evm::Schedule;
 use ethjson;
 use io::{IoContext, IoHandler, TimerToken, IoService, IoChannel};
@@ -35,8 +37,6 @@ use service::ClientIoMessage;
 use transaction::SignedTransaction;
 use env_info::EnvInfo;
 use builtin::Builtin;
-use blockchain::extras::BlockDetails;
-use views::HeaderView;
 
 /// `AuthorityRound` params.
 #[derive(Debug, PartialEq)]
@@ -68,18 +68,20 @@ pub struct AuthorityRound {
 	params: CommonParams,
 	our_params: AuthorityRoundParams,
 	builtins: BTreeMap<Address, Builtin>,
-	transition_service: IoService<BlockArrived>,
+	transition_service: IoService<()>,
 	message_channel: Mutex<Option<IoChannel<ClientIoMessage>>>,
 	step: AtomicUsize,
 	proposed: AtomicBool,
+	account_provider: Mutex<Option<Arc<AccountProvider>>>,
+	password: RwLock<Option<String>>,
 }
 
 fn header_step(header: &Header) -> Result<usize, ::rlp::DecoderError> {
-	UntrustedRlp::new(&header.seal()[0]).as_val()
+	UntrustedRlp::new(&header.seal().get(0).expect("was either checked with verify_block_basic or is genesis; has 2 fields; qed (Make sure the spec file has a correct genesis seal)")).as_val()
 }
 
 fn header_signature(header: &Header) -> Result<Signature, ::rlp::DecoderError> {
-	UntrustedRlp::new(&header.seal()[1]).as_val::<H520>().map(Into::into)
+	UntrustedRlp::new(&header.seal().get(1).expect("was checked with verify_block_basic; has 2 fields; qed")).as_val::<H520>().map(Into::into)
 }
 
 trait AsMillis {
@@ -101,10 +103,12 @@ impl AuthorityRound {
 				params: params,
 				our_params: our_params,
 				builtins: builtins,
-				transition_service: try!(IoService::<BlockArrived>::start()),
+				transition_service: try!(IoService::<()>::start()),
 				message_channel: Mutex::new(None),
 				step: AtomicUsize::new(initial_step),
-				proposed: AtomicBool::new(false)
+				proposed: AtomicBool::new(false),
+				account_provider: Mutex::new(None),
+				password: RwLock::new(None),
 			});
 		let handler = TransitionHandler { engine: Arc::downgrade(&engine) };
 		try!(engine.transition_service.register_handler(Arc::new(handler)));
@@ -143,20 +147,17 @@ struct TransitionHandler {
 	engine: Weak<AuthorityRound>,
 }
 
-#[derive(Clone)]
-struct BlockArrived;
-
 const ENGINE_TIMEOUT_TOKEN: TimerToken = 23;
 
-impl IoHandler<BlockArrived> for TransitionHandler {
-	fn initialize(&self, io: &IoContext<BlockArrived>) {
+impl IoHandler<()> for TransitionHandler {
+	fn initialize(&self, io: &IoContext<()>) {
 		if let Some(engine) = self.engine.upgrade() {
 			io.register_timer_once(ENGINE_TIMEOUT_TOKEN, engine.remaining_step_duration().as_millis())
 				.unwrap_or_else(|e| warn!(target: "poa", "Failed to start consensus step timer: {}.", e))
 		}
 	}
 
-	fn timeout(&self, io: &IoContext<BlockArrived>, timer: TimerToken) {
+	fn timeout(&self, io: &IoContext<()>, timer: TimerToken) {
 		if timer == ENGINE_TIMEOUT_TOKEN {
 			if let Some(engine) = self.engine.upgrade() {
 				engine.step.fetch_add(1, AtomicOrdering::SeqCst);
@@ -208,10 +209,6 @@ impl Engine for AuthorityRound {
 		});
 	}
 
-	/// Apply the block reward on finalisation of the block.
-	/// This assumes that all uncles are valid uncles (i.e. of at least one generation before the current).
-	fn on_close_block(&self, _block: &mut ExecutedBlock) {}
-
 	fn is_sealer(&self, author: &Address) -> Option<bool> {
 		let p = &self.our_params;
 		Some(p.authorities.contains(author))
@@ -221,14 +218,14 @@ impl Engine for AuthorityRound {
 	///
 	/// This operation is synchronous and may (quite reasonably) not be available, in which `false` will
 	/// be returned.
-	fn generate_seal(&self, block: &ExecutedBlock, accounts: Option<&AccountProvider>) -> Option<Vec<Bytes>> {
+	fn generate_seal(&self, block: &ExecutedBlock) -> Option<Vec<Bytes>> {
 		if self.proposed.load(AtomicOrdering::SeqCst) { return None; }
 		let header = block.header();
 		let step = self.step();
 		if self.is_step_proposer(step, header.author()) {
-			if let Some(ap) = accounts {
+			if let Some(ref ap) = *self.account_provider.lock() {
 				// Account should be permanently unlocked, otherwise sealing will fail.
-				if let Ok(signature) = ap.sign(*header.author(), None, header.bare_hash()) {
+				if let Ok(signature) = ap.sign(*header.author(), self.password.read().clone(), header.bare_hash()) {
 					trace!(target: "poa", "generate_seal: Issuing a block for step {}.", step);
 					self.proposed.store(true, AtomicOrdering::SeqCst);
 					return Some(vec![encode(&step).to_vec(), encode(&(&*signature as &[u8])).to_vec()]);
@@ -303,23 +300,30 @@ impl Engine for AuthorityRound {
 		t.sender().map(|_|()) // Perform EC recovery and cache sender
 	}
 
-	fn register_message_channel(&self, message_channel: IoChannel<ClientIoMessage>) {
-		let mut guard = self.message_channel.lock();
-		*guard = Some(message_channel);
-	}
-
 	fn is_new_best_block(&self, _best_total_difficulty: U256, best_header: HeaderView, _parent_details: &BlockDetails, new_header: &HeaderView) -> bool {
 		let new_number = new_header.number();
 		let best_number = best_header.number();
 		if new_number != best_number {
 			new_number > best_number
 		} else {
-			// Take the oldest step at given height.
-			let new_step: usize = Rlp::new(&new_header.seal()[0]).as_val();
+ 			// Take the oldest step at given height.
+ 			let new_step: usize = Rlp::new(&new_header.seal()[0]).as_val();
 			let best_step: usize = Rlp::new(&best_header.seal()[0]).as_val();
 			new_step < best_step
 		}
 	}
+
+	fn register_message_channel(&self, message_channel: IoChannel<ClientIoMessage>) {
+		*self.message_channel.lock() = Some(message_channel);
+	}
+
+	fn set_signer(&self, _address: Address, password: String) {
+		*self.password.write() = Some(password);
+	}
+
+	fn register_account_provider(&self, account_provider: Arc<AccountProvider>) {
+		*self.account_provider.lock() = Some(account_provider);
+	}
 }
 
 #[cfg(test)]
@@ -387,12 +391,11 @@ mod tests {
 	fn generates_seal_and_does_not_double_propose() {
 		let tap = AccountProvider::transient_provider();
 		let addr1 = tap.insert_account("1".sha3(), "1").unwrap();
-		tap.unlock_account_permanently(addr1, "1".into()).unwrap();
 		let addr2 = tap.insert_account("2".sha3(), "2").unwrap();
-		tap.unlock_account_permanently(addr2, "2".into()).unwrap();
 
 		let spec = Spec::new_test_round();
 		let engine = &*spec.engine;
+		engine.register_account_provider(Arc::new(tap));
 		let genesis_header = spec.genesis_header();
 		let mut db1 = get_temp_state_db().take();
 		spec.ensure_db_good(&mut db1, &TrieFactory::new(TrieSpec::Secure)).unwrap();
@@ -404,16 +407,18 @@ mod tests {
 		let b2 = OpenBlock::new(engine, Default::default(), false, db2, &genesis_header, last_hashes, addr2, (3141562.into(), 31415620.into()), vec![]).unwrap();
 		let b2 = b2.close_and_lock();
 
-		if let Some(seal) = engine.generate_seal(b1.block(), Some(&tap)) {
+		engine.set_signer(addr1, "1".into());
+		if let Some(seal) = engine.generate_seal(b1.block()) {
 			assert!(b1.clone().try_seal(engine, seal).is_ok());
 			// Second proposal is forbidden.
-			assert!(engine.generate_seal(b1.block(), Some(&tap)).is_none());
+			assert!(engine.generate_seal(b1.block()).is_none());
 		}
 
-		if let Some(seal) = engine.generate_seal(b2.block(), Some(&tap)) {
+		engine.set_signer(addr2, "2".into());
+		if let Some(seal) = engine.generate_seal(b2.block()) {
 			assert!(b2.clone().try_seal(engine, seal).is_ok());
 			// Second proposal is forbidden.
-			assert!(engine.generate_seal(b2.block(), Some(&tap)).is_none());
+			assert!(engine.generate_seal(b2.block()).is_none());
 		}
 	}
 
diff --git a/ethcore/src/engines/basic_authority.rs b/ethcore/src/engines/basic_authority.rs
index fb2f9bde6..1070d3a3d 100644
--- a/ethcore/src/engines/basic_authority.rs
+++ b/ethcore/src/engines/basic_authority.rs
@@ -58,6 +58,8 @@ pub struct BasicAuthority {
 	params: CommonParams,
 	our_params: BasicAuthorityParams,
 	builtins: BTreeMap<Address, Builtin>,
+	account_provider: Mutex<Option<Arc<AccountProvider>>>,
+	password: RwLock<Option<String>>,
 }
 
 impl BasicAuthority {
@@ -67,6 +69,8 @@ impl BasicAuthority {
 			params: params,
 			our_params: our_params,
 			builtins: builtins,
+			account_provider: Mutex::new(None),
+			password: RwLock::new(None),
 		}
 	}
 }
@@ -98,13 +102,8 @@ impl Engine for BasicAuthority {
 				max(gas_floor_target, gas_limit - gas_limit / bound_divisor + 1.into())
 			}
 		});
-//		info!("ethash: populate_from_parent #{}: difficulty={} and gas_limit={}", header.number, header.difficulty, header.gas_limit);
 	}
 
-	/// Apply the block reward on finalisation of the block.
-	/// This assumes that all uncles are valid uncles (i.e. of at least one generation before the current).
-	fn on_close_block(&self, _block: &mut ExecutedBlock) {}
-
 	fn is_sealer(&self, author: &Address) -> Option<bool> {
 		Some(self.our_params.authorities.contains(author))
 	}
@@ -113,12 +112,12 @@ impl Engine for BasicAuthority {
 	///
 	/// This operation is synchronous and may (quite reasonably) not be available, in which `false` will
 	/// be returned.
-	fn generate_seal(&self, block: &ExecutedBlock, accounts: Option<&AccountProvider>) -> Option<Vec<Bytes>> {
-		if let Some(ap) = accounts {
+	fn generate_seal(&self, block: &ExecutedBlock) -> Option<Vec<Bytes>> {
+		if let Some(ref ap) = *self.account_provider.lock() {
 			let header = block.header();
 			let message = header.bare_hash();
 			// account should be pernamently unlocked, otherwise sealing will fail
-			if let Ok(signature) = ap.sign(*block.header().author(), None, message) {
+			if let Ok(signature) = ap.sign(*block.header().author(), self.password.read().clone(), message) {
 				return Some(vec![::rlp::encode(&(&*signature as &[u8])).to_vec()]);
 			} else {
 				trace!(target: "basicauthority", "generate_seal: FAIL: accounts secret key unavailable");
@@ -179,6 +178,14 @@ impl Engine for BasicAuthority {
 	fn verify_transaction(&self, t: &SignedTransaction, _header: &Header) -> Result<(), Error> {
 		t.sender().map(|_|()) // Perform EC recovery and cache sender
 	}
+
+	fn set_signer(&self, _address: Address, password: String) {
+		*self.password.write() = Some(password);
+	}
+
+	fn register_account_provider(&self, ap: Arc<AccountProvider>) {
+		*self.account_provider.lock() = Some(ap);
+	}
 }
 
 #[cfg(test)]
@@ -250,10 +257,11 @@ mod tests {
 	fn can_generate_seal() {
 		let tap = AccountProvider::transient_provider();
 		let addr = tap.insert_account("".sha3(), "").unwrap();
-		tap.unlock_account_permanently(addr, "".into()).unwrap();
 
 		let spec = new_test_authority();
 		let engine = &*spec.engine;
+		engine.set_signer(addr, "".into());
+		engine.register_account_provider(Arc::new(tap));
 		let genesis_header = spec.genesis_header();
 		let mut db_result = get_temp_state_db();
 		let mut db = db_result.take();
@@ -261,7 +269,7 @@ mod tests {
 		let last_hashes = Arc::new(vec![genesis_header.hash()]);
 		let b = OpenBlock::new(engine, Default::default(), false, db, &genesis_header, last_hashes, addr, (3141562.into(), 31415620.into()), vec![]).unwrap();
 		let b = b.close_and_lock();
-		let seal = engine.generate_seal(b.block(), Some(&tap)).unwrap();
+		let seal = engine.generate_seal(b.block()).unwrap();
 		assert!(b.try_seal(engine, seal).is_ok());
 	}
 
diff --git a/ethcore/src/engines/instant_seal.rs b/ethcore/src/engines/instant_seal.rs
index f50f7344b..83335fb03 100644
--- a/ethcore/src/engines/instant_seal.rs
+++ b/ethcore/src/engines/instant_seal.rs
@@ -23,7 +23,6 @@ use spec::CommonParams;
 use evm::Schedule;
 use block::ExecutedBlock;
 use util::Bytes;
-use account_provider::AccountProvider;
 
 /// An engine which does not provide any consensus mechanism, just seals blocks internally.
 pub struct InstantSeal {
@@ -60,7 +59,7 @@ impl Engine for InstantSeal {
 
 	fn is_sealer(&self, _author: &Address) -> Option<bool> { Some(true) }
 
-	fn generate_seal(&self, _block: &ExecutedBlock, _accounts: Option<&AccountProvider>) -> Option<Vec<Bytes>> {
+	fn generate_seal(&self, _block: &ExecutedBlock) -> Option<Vec<Bytes>> {
 		Some(Vec::new())
 	}
 }
@@ -70,16 +69,12 @@ mod tests {
 	use util::*;
 	use util::trie::TrieSpec;
 	use tests::helpers::*;
-	use account_provider::AccountProvider;
 	use spec::Spec;
 	use header::Header;
 	use block::*;
 
 	#[test]
 	fn instant_can_seal() {
-		let tap = AccountProvider::transient_provider();
-		let addr = tap.insert_account("".sha3(), "").unwrap();
-
 		let spec = Spec::new_instant();
 		let engine = &*spec.engine;
 		let genesis_header = spec.genesis_header();
@@ -87,10 +82,9 @@ mod tests {
 		let mut db = db_result.take();
 		spec.ensure_db_good(&mut db, &TrieFactory::new(TrieSpec::Secure)).unwrap();
 		let last_hashes = Arc::new(vec![genesis_header.hash()]);
-		let b = OpenBlock::new(engine, Default::default(), false, db, &genesis_header, last_hashes, addr, (3141562.into(), 31415620.into()), vec![]).unwrap();
+		let b = OpenBlock::new(engine, Default::default(), false, db, &genesis_header, last_hashes, Address::default(), (3141562.into(), 31415620.into()), vec![]).unwrap();
 		let b = b.close_and_lock();
-		// Seal with empty AccountProvider.
-		let seal = engine.generate_seal(b.block(), Some(&tap)).unwrap();
+		let seal = engine.generate_seal(b.block()).unwrap();
 		assert!(b.try_seal(engine, seal).is_ok());
 	}
 
diff --git a/ethcore/src/engines/mod.rs b/ethcore/src/engines/mod.rs
index d216c88b6..d7ff06248 100644
--- a/ethcore/src/engines/mod.rs
+++ b/ethcore/src/engines/mod.rs
@@ -94,7 +94,7 @@ pub trait Engine : Sync + Send {
 	///
 	/// This operation is synchronous and may (quite reasonably) not be available, in which None will
 	/// be returned.
-	fn generate_seal(&self, _block: &ExecutedBlock, _accounts: Option<&AccountProvider>) -> Option<Vec<Bytes>> { None }
+	fn generate_seal(&self, _block: &ExecutedBlock) -> Option<Vec<Bytes>> { None }
 
 	/// Phase 1 quick block verification. Only does checks that are cheap. `block` (the header's full block)
 	/// may be provided for additional checks. Returns either a null `Ok` or a general error detailing the problem with import.
@@ -147,11 +147,17 @@ pub trait Engine : Sync + Send {
 		self.builtins().get(a).expect("attempted to execute nonexistent builtin").execute(input, output);
 	}
 
-	/// Add a channel for communication with Client which can be used for sealing.
-	fn register_message_channel(&self, _message_channel: IoChannel<ClientIoMessage>) {}
-
 	/// Check if new block should be chosen as the one  in chain.
 	fn is_new_best_block(&self, best_total_difficulty: U256, _best_header: HeaderView, parent_details: &BlockDetails, new_header: &HeaderView) -> bool {
 		ethash::is_new_best_block(best_total_difficulty, parent_details, new_header)
 	}
+
+	/// Register an account which signs consensus messages.
+	fn set_signer(&self, _address: Address, _password: String) {}
+
+	/// Add a channel for communication with Client which can be used for sealing.
+	fn register_message_channel(&self, _message_channel: IoChannel<ClientIoMessage>) {}
+
+	/// Add an account provider useful for Engines that sign stuff.
+	fn register_account_provider(&self, _account_provider: Arc<AccountProvider>) {}
 }
diff --git a/ethcore/src/miner/miner.rs b/ethcore/src/miner/miner.rs
index a543e608d..8d1f55567 100644
--- a/ethcore/src/miner/miner.rs
+++ b/ethcore/src/miner/miner.rs
@@ -19,7 +19,7 @@ use std::time::{Instant, Duration};
 
 use util::*;
 use util::using_queue::{UsingQueue, GetAction};
-use account_provider::AccountProvider;
+use account_provider::{AccountProvider, Error as AccountError};
 use views::{BlockView, HeaderView};
 use header::Header;
 use state::{State, CleanupMode};
@@ -464,15 +464,12 @@ impl Miner {
 	/// Attempts to perform internal sealing (one that does not require work) to return Ok(sealed),
 	/// Err(Some(block)) returns for unsuccesful sealing while Err(None) indicates misspecified engine.
 	fn seal_block_internally(&self, block: ClosedBlock) -> Result<SealedBlock, Option<ClosedBlock>> {
-		trace!(target: "miner", "seal_block_internally: block has transaction - attempting internal seal.");
-		let s = self.engine.generate_seal(block.block(), match self.accounts {
-			Some(ref x) => Some(&**x),
-			None => None,
-		});
+		trace!(target: "miner", "seal_block_internally: attempting internal seal.");
+		let s = self.engine.generate_seal(block.block());
 		if let Some(seal) = s {
 			trace!(target: "miner", "seal_block_internally: managed internal seal. importing...");
-			block.lock().try_seal(&*self.engine, seal).or_else(|_| {
-				warn!("prepare_sealing: ERROR: try_seal failed when given internally generated seal. WTF?");
+			block.lock().try_seal(&*self.engine, seal).or_else(|(e, _)| {
+				warn!("prepare_sealing: ERROR: try_seal failed when given internally generated seal: {}", e);
 				Err(None)
 			})
 		} else {
@@ -485,7 +482,7 @@ impl Miner {
 	fn seal_and_import_block_internally(&self, chain: &MiningBlockChainClient, block: ClosedBlock) -> bool {
 		if !block.transactions().is_empty() || self.forced_sealing() {
 			if let Ok(sealed) = self.seal_block_internally(block) {
-				if chain.import_block(sealed.rlp_bytes()).is_ok() {
+				if chain.import_sealed_block(sealed).is_ok() {
 					trace!(target: "miner", "import_block_internally: imported internally sealed block");
 					return true
 				}
@@ -740,6 +737,19 @@ impl MinerService for Miner {
 		*self.author.write() = author;
 	}
 
+	fn set_engine_signer(&self, address: Address, password: String) -> Result<(), AccountError> {
+		if self.seals_internally {
+			if let Some(ref ap) = self.accounts {
+				try!(ap.sign(address.clone(), Some(password.clone()), Default::default()));
+			}
+			let mut sealing_work = self.sealing_work.lock();
+			sealing_work.enabled = self.engine.is_sealer(&address).unwrap_or(false);
+			*self.author.write() = address;
+			self.engine.set_signer(address, password);
+		}
+		Ok(())
+	}
+
 	fn set_extra_data(&self, extra_data: Bytes) {
 		*self.extra_data.write() = extra_data;
 	}
@@ -1042,7 +1052,7 @@ impl MinerService for Miner {
 		ret.map(f)
 	}
 
-	fn submit_seal(&self, chain: &MiningBlockChainClient, pow_hash: H256, seal: Vec<Bytes>) -> Result<(), Error> {
+	fn submit_seal(&self, chain: &MiningBlockChainClient, block_hash: H256, seal: Vec<Bytes>) -> Result<(), Error> {
 		let result =
 			if let Some(b) = self.sealing_work.lock().queue.get_used_if(
 				if self.options.enable_resubmission {
@@ -1050,22 +1060,22 @@ impl MinerService for Miner {
 				} else {
 					GetAction::Take
 				},
-				|b| &b.hash() == &pow_hash
+				|b| &b.hash() == &block_hash
 			) {
-				trace!(target: "miner", "Sealing block {}={}={} with seal {:?}", pow_hash, b.hash(), b.header().bare_hash(), seal);
+				trace!(target: "miner", "Submitted block {}={}={} with seal {:?}", block_hash, b.hash(), b.header().bare_hash(), seal);
 				b.lock().try_seal(&*self.engine, seal).or_else(|(e, _)| {
 					warn!(target: "miner", "Mined solution rejected: {}", e);
 					Err(Error::PowInvalid)
 				})
 			} else {
-				warn!(target: "miner", "Mined solution rejected: Block unknown or out of date.");
+				warn!(target: "miner", "Submitted solution rejected: Block unknown or out of date.");
 				Err(Error::PowHashInvalid)
 			};
 		result.and_then(|sealed| {
 			let n = sealed.header().number();
 			let h = sealed.header().hash();
 			try!(chain.import_sealed_block(sealed));
-			info!(target: "miner", "Mined block imported OK. #{}: {}", Colour::White.bold().paint(format!("{}", n)), Colour::White.bold().paint(h.hex()));
+			info!(target: "miner", "Submitted block imported OK. #{}: {}", Colour::White.bold().paint(format!("{}", n)), Colour::White.bold().paint(h.hex()));
 			Ok(())
 		})
 	}
diff --git a/ethcore/src/miner/mod.rs b/ethcore/src/miner/mod.rs
index 1fb2244fd..8c466581b 100644
--- a/ethcore/src/miner/mod.rs
+++ b/ethcore/src/miner/mod.rs
@@ -76,6 +76,9 @@ pub trait MinerService : Send + Sync {
 	/// Set the author that we will seal blocks as.
 	fn set_author(&self, author: Address);
 
+	/// Set info necessary to sign consensus messages.
+	fn set_engine_signer(&self, address: Address, password: String) -> Result<(), ::account_provider::Error>;
+
 	/// Get the extra_data that we will seal blocks with.
 	fn extra_data(&self) -> Bytes;
 
diff --git a/parity/cli/config.full.toml b/parity/cli/config.full.toml
index ffb0848ea..a35d4c389 100644
--- a/parity/cli/config.full.toml
+++ b/parity/cli/config.full.toml
@@ -61,6 +61,7 @@ pass = "test_pass"
 
 [mining]
 author = "0xdeadbeefcafe0000000000000000000000000001"
+engine_signer = "0xdeadbeefcafe0000000000000000000000000001"
 force_sealing = true
 reseal_on_txs = "all"
 reseal_min_period = 4000
diff --git a/parity/cli/config.toml b/parity/cli/config.toml
index 74f3477f3..608999799 100644
--- a/parity/cli/config.toml
+++ b/parity/cli/config.toml
@@ -40,6 +40,7 @@ pass = "password"
 
 [mining]
 author = "0xdeadbeefcafe0000000000000000000000000001"
+engine_signer = "0xdeadbeefcafe0000000000000000000000000001"
 force_sealing = true
 reseal_on_txs = "all"
 reseal_min_period = 4000
diff --git a/parity/cli/mod.rs b/parity/cli/mod.rs
index 01767da42..f5e2cbf4a 100644
--- a/parity/cli/mod.rs
+++ b/parity/cli/mod.rs
@@ -178,6 +178,8 @@ usage! {
 		// -- Sealing/Mining Options
 		flag_author: Option<String> = None,
 			or |c: &Config| otry!(c.mining).author.clone().map(Some),
+		flag_engine_signer: Option<String> = None,
+			or |c: &Config| otry!(c.mining).engine_signer.clone().map(Some),
 		flag_force_sealing: bool = false,
 			or |c: &Config| otry!(c.mining).force_sealing.clone(),
 		flag_reseal_on_txs: String = "own",
@@ -371,6 +373,7 @@ struct Dapps {
 #[derive(Default, Debug, PartialEq, RustcDecodable)]
 struct Mining {
 	author: Option<String>,
+	engine_signer: Option<String>,
 	force_sealing: Option<bool>,
 	reseal_on_txs: Option<String>,
 	reseal_min_period: Option<u64>,
@@ -575,6 +578,7 @@ mod tests {
 
 			// -- Sealing/Mining Options
 			flag_author: Some("0xdeadbeefcafe0000000000000000000000000001".into()),
+			flag_engine_signer: Some("0xdeadbeefcafe0000000000000000000000000001".into()),
 			flag_force_sealing: true,
 			flag_reseal_on_txs: "all".into(),
 			flag_reseal_min_period: 4000u64,
@@ -746,6 +750,7 @@ mod tests {
 			}),
 			mining: Some(Mining {
 				author: Some("0xdeadbeefcafe0000000000000000000000000001".into()),
+				engine_signer: Some("0xdeadbeefcafe0000000000000000000000000001".into()),
 				force_sealing: Some(true),
 				reseal_on_txs: Some("all".into()),
 				reseal_min_period: Some(4000),
diff --git a/parity/cli/usage.txt b/parity/cli/usage.txt
index 02e7e00ec..58518bd48 100644
--- a/parity/cli/usage.txt
+++ b/parity/cli/usage.txt
@@ -149,6 +149,10 @@ Sealing/Mining Options:
                            for sending block rewards from sealed blocks.
                            NOTE: MINING WILL NOT WORK WITHOUT THIS OPTION.
                            (default: {flag_author:?})
+  --engine-signer ADDRESS  Specify the address which should be used to
+                           sign consensus messages and issue blocks.
+                           Relevant only to non-PoW chains.
+                           (default: {flag_engine_signer:?})
   --force-sealing          Force the node to author new blocks as if it were
                            always sealing/mining.
                            (default: {flag_force_sealing})
diff --git a/parity/configuration.rs b/parity/configuration.rs
index 6b6bd3229..60116ef99 100644
--- a/parity/configuration.rs
+++ b/parity/configuration.rs
@@ -305,6 +305,7 @@ impl Configuration {
 			gas_floor_target: try!(to_u256(&self.args.flag_gas_floor_target)),
 			gas_ceil_target: try!(to_u256(&self.args.flag_gas_cap)),
 			transactions_limit: self.args.flag_tx_queue_size,
+			engine_signer: try!(self.engine_signer()),
 		};
 
 		Ok(extras)
@@ -314,6 +315,10 @@ impl Configuration {
 		to_address(self.args.flag_etherbase.clone().or(self.args.flag_author.clone()))
 	}
 
+	fn engine_signer(&self) -> Result<Address, String> {
+		to_address(self.args.flag_engine_signer.clone())
+	}
+
 	fn format(&self) -> Result<Option<DataFormat>, String> {
 		match self.args.flag_format {
 			Some(ref f) => Ok(Some(try!(f.parse()))),
diff --git a/parity/helpers.rs b/parity/helpers.rs
index ab0dafddd..654270b64 100644
--- a/parity/helpers.rs
+++ b/parity/helpers.rs
@@ -300,14 +300,14 @@ pub fn password_prompt() -> Result<String, String> {
 
 /// Read a password from password file.
 pub fn password_from_file(path: String) -> Result<String, String> {
-	let passwords = try!(passwords_from_files(vec![path]));
+	let passwords = try!(passwords_from_files(&[path]));
 	// use only first password from the file
 	passwords.get(0).map(String::to_owned)
 		.ok_or_else(|| "Password file seems to be empty.".to_owned())
 }
 
 /// Reads passwords from files. Treats each line as a separate password.
-pub fn passwords_from_files(files: Vec<String>) -> Result<Vec<String>, String> {
+pub fn passwords_from_files(files: &[String]) -> Result<Vec<String>, String> {
 	let passwords = files.iter().map(|filename| {
 		let file = try!(File::open(filename).map_err(|_| format!("{} Unable to read password file. Ensure it exists and permissions are correct.", filename)));
 		let reader = BufReader::new(&file);
diff --git a/parity/params.rs b/parity/params.rs
index 3ce07e889..25ddc8814 100644
--- a/parity/params.rs
+++ b/parity/params.rs
@@ -204,6 +204,7 @@ pub struct MinerExtras {
 	pub gas_floor_target: U256,
 	pub gas_ceil_target: U256,
 	pub transactions_limit: usize,
+	pub engine_signer: Address,
 }
 
 impl Default for MinerExtras {
@@ -214,6 +215,7 @@ impl Default for MinerExtras {
 			gas_floor_target: U256::from(4_700_000),
 			gas_ceil_target: U256::from(6_283_184),
 			transactions_limit: 1024,
+			engine_signer: Default::default(),
 		}
 	}
 }
diff --git a/parity/run.rs b/parity/run.rs
index 05f7576c4..cf39b5528 100644
--- a/parity/run.rs
+++ b/parity/run.rs
@@ -207,8 +207,13 @@ pub fn execute(cmd: RunCmd, logger: Arc<RotatingLogger>) -> Result<(), String> {
 	sync_config.warp_sync = cmd.warp_sync;
 	sync_config.download_old_blocks = cmd.download_old_blocks;
 
+	let passwords = try!(passwords_from_files(&cmd.acc_conf.password_files));
+
 	// prepare account provider
-	let account_provider = Arc::new(try!(prepare_account_provider(&cmd.dirs, cmd.acc_conf)));
+	let account_provider = Arc::new(try!(prepare_account_provider(&cmd.dirs, cmd.acc_conf, &passwords)));
+
+	// let the Engine access the accounts
+	spec.engine.register_account_provider(account_provider.clone());
 
 	// create miner
 	let miner = Miner::new(cmd.miner_options, cmd.gas_pricer.into(), &spec, Some(account_provider.clone()));
@@ -217,6 +222,12 @@ pub fn execute(cmd: RunCmd, logger: Arc<RotatingLogger>) -> Result<(), String> {
 	miner.set_gas_ceil_target(cmd.miner_extras.gas_ceil_target);
 	miner.set_extra_data(cmd.miner_extras.extra_data);
 	miner.set_transactions_limit(cmd.miner_extras.transactions_limit);
+	let engine_signer = cmd.miner_extras.engine_signer;
+	if engine_signer != Default::default() {
+		if !passwords.into_iter().any(|p| miner.set_engine_signer(engine_signer, p).is_ok()) {
+			return Err(format!("No password found for the consensus signer {}. Make sure valid password is present in files passed using `--password`.", engine_signer));
+		}
+	}
 
 	// create client config
 	let mut client_config = to_client_config(
@@ -425,19 +436,17 @@ fn daemonize(_pid_file: String) -> Result<(), String> {
 	Err("daemon is no supported on windows".into())
 }
 
-fn prepare_account_provider(dirs: &Directories, cfg: AccountsConfig) -> Result<AccountProvider, String> {
+fn prepare_account_provider(dirs: &Directories, cfg: AccountsConfig, passwords: &[String]) -> Result<AccountProvider, String> {
 	use ethcore::ethstore::EthStore;
 	use ethcore::ethstore::dir::DiskDirectory;
 
-	let passwords = try!(passwords_from_files(cfg.password_files));
-
 	let dir = Box::new(try!(DiskDirectory::create(dirs.keys.clone()).map_err(|e| format!("Could not open keys directory: {}", e))));
 	let account_service = AccountProvider::new(Box::new(
 		try!(EthStore::open_with_iterations(dir, cfg.iterations).map_err(|e| format!("Could not open keys directory: {}", e)))
 	));
 
 	for a in cfg.unlocked_accounts {
-		if passwords.iter().find(|p| account_service.unlock_account_permanently(a, (*p).clone()).is_ok()).is_none() {
+		if !passwords.iter().any(|p| account_service.unlock_account_permanently(a, (*p).clone()).is_ok()) {
 			return Err(format!("No password found to unlock account {}. Make sure valid password is present in files passed using `--password`.", a));
 		}
 	}
diff --git a/rpc/src/v1/impls/parity_set.rs b/rpc/src/v1/impls/parity_set.rs
index 47634d518..92de99a1f 100644
--- a/rpc/src/v1/impls/parity_set.rs
+++ b/rpc/src/v1/impls/parity_set.rs
@@ -116,6 +116,12 @@ impl<C, M, F> ParitySet for ParitySetClient<C, M, F> where
 		Ok(true)
 	}
 
+	fn set_engine_signer(&self, address: H160, password: String) -> Result<bool, Error> {
+		try!(self.active());
+		try!(take_weak!(self.miner).set_engine_signer(address.into(), password).map_err(Into::into).map_err(errors::from_password_error));
+		Ok(true)
+	}
+
 	fn set_transactions_limit(&self, limit: usize) -> Result<bool, Error> {
 		try!(self.active());
 
diff --git a/rpc/src/v1/tests/eth.rs b/rpc/src/v1/tests/eth.rs
index 7894fa111..3aa83fec9 100644
--- a/rpc/src/v1/tests/eth.rs
+++ b/rpc/src/v1/tests/eth.rs
@@ -116,6 +116,7 @@ impl EthTester {
 	fn from_spec(spec: Spec) -> Self {
 		let dir = RandomTempPath::new();
 		let account_provider = account_provider();
+		spec.engine.register_account_provider(account_provider.clone());
 		let miner_service = miner_service(&spec, account_provider.clone());
 		let snapshot_service = snapshot_service();
 
diff --git a/rpc/src/v1/tests/helpers/miner_service.rs b/rpc/src/v1/tests/helpers/miner_service.rs
index ad55faa7b..39fba8406 100644
--- a/rpc/src/v1/tests/helpers/miner_service.rs
+++ b/rpc/src/v1/tests/helpers/miner_service.rs
@@ -25,6 +25,7 @@ use ethcore::header::BlockNumber;
 use ethcore::transaction::SignedTransaction;
 use ethcore::receipt::{Receipt, RichReceipt};
 use ethcore::miner::{MinerService, MinerStatus, TransactionImportResult, LocalTransactionStatus};
+use ethcore::account_provider::Error as AccountError;
 
 /// Test miner service.
 pub struct TestMinerService {
@@ -40,6 +41,8 @@ pub struct TestMinerService {
 	pub pending_receipts: Mutex<BTreeMap<H256, Receipt>>,
 	/// Last nonces.
 	pub last_nonces: RwLock<HashMap<Address, U256>>,
+	/// Password held by Engine.
+	pub password: RwLock<String>,
 
 	min_gas_price: RwLock<U256>,
 	gas_range_target: RwLock<(U256, U256)>,
@@ -61,6 +64,7 @@ impl Default for TestMinerService {
 			min_gas_price: RwLock::new(U256::from(20_000_000)),
 			gas_range_target: RwLock::new((U256::from(12345), U256::from(54321))),
 			author: RwLock::new(Address::zero()),
+			password: RwLock::new(String::new()),
 			extra_data: RwLock::new(vec![1, 2, 3, 4]),
 			limit: RwLock::new(1024),
 			tx_gas_limit: RwLock::new(!U256::zero()),
@@ -83,6 +87,12 @@ impl MinerService for TestMinerService {
 		*self.author.write() = author;
 	}
 
+	fn set_engine_signer(&self, address: Address, password: String) -> Result<(), AccountError> {
+		*self.author.write() = address;
+		*self.password.write() = password;
+		Ok(())
+	}
+
 	fn set_extra_data(&self, extra_data: Bytes) {
 		*self.extra_data.write() = extra_data;
 	}
diff --git a/rpc/src/v1/tests/mocked/parity_set.rs b/rpc/src/v1/tests/mocked/parity_set.rs
index 01f33e251..55f155693 100644
--- a/rpc/src/v1/tests/mocked/parity_set.rs
+++ b/rpc/src/v1/tests/mocked/parity_set.rs
@@ -106,6 +106,23 @@ fn rpc_parity_set_author() {
 	assert_eq!(miner.author(), Address::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap());
 }
 
+#[test]
+fn rpc_parity_set_engine_signer() {
+	let miner = miner_service();
+	let client = client_service();
+	let network = network_service();
+	let io = IoHandler::new();
+	io.add_delegate(parity_set_client(&client, &miner, &network).to_delegate());
+
+	let request = r#"{"jsonrpc": "2.0", "method": "parity_setEngineSigner", "params":["0xcd1722f3947def4cf144679da39c4c32bdc35681", "password"], "id": 1}"#;
+	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;
+
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
+	assert_eq!(miner.author(), Address::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap());
+	assert_eq!(*miner.password.read(), "password".to_string());
+}
+
+
 #[test]
 fn rpc_parity_set_transactions_limit() {
 	let miner = miner_service();
diff --git a/rpc/src/v1/traits/parity_set.rs b/rpc/src/v1/traits/parity_set.rs
index c83eff022..c40abd01f 100644
--- a/rpc/src/v1/traits/parity_set.rs
+++ b/rpc/src/v1/traits/parity_set.rs
@@ -44,6 +44,10 @@ build_rpc_trait! {
 		#[rpc(name = "parity_setAuthor")]
 		fn set_author(&self, H160) -> Result<bool, Error>;
 
+		/// Sets account for signing consensus messages.
+		#[rpc(name = "parity_setEngineSigner")]
+		fn set_engine_signer(&self, H160, String) -> Result<bool, Error>;
+
 		/// Sets the limits for transaction queue.
 		#[rpc(name = "parity_setTransactionsLimit")]
 		fn set_transactions_limit(&self, usize) -> Result<bool, Error>;