SecretStore: Kovan integration initial commit

ethcore/native_contracts/build.rs

@@ -26,6 +26,7 @@ const REGISTRY_ABI: &'static str = include_str!("res/registrar.json");
 const URLHINT_ABI: &'static str = include_str!("res/urlhint.json");
 const SERVICE_TRANSACTION_ABI: &'static str = include_str!("res/service_transaction.json");
 const SECRETSTORE_ACL_STORAGE_ABI: &'static str = include_str!("res/secretstore_acl_storage.json");
+const SECRETSTORE_SERVICE_ABI: &'static str = include_str!("res/secretstore_service.json");
 const VALIDATOR_SET_ABI: &'static str = include_str!("res/validator_set.json");
 const VALIDATOR_REPORT_ABI: &'static str = include_str!("res/validator_report.json");
 const PEER_SET_ABI: &'static str = include_str!("res/peer_set.json");
@@ -53,6 +54,7 @@ fn main() {
 	build_file("Urlhint", URLHINT_ABI, "urlhint.rs");
 	build_file("ServiceTransactionChecker", SERVICE_TRANSACTION_ABI, "service_transaction.rs");
 	build_file("SecretStoreAclStorage", SECRETSTORE_ACL_STORAGE_ABI, "secretstore_acl_storage.rs");
+	build_file("SecretStoreService", SECRETSTORE_SERVICE_ABI, "secretstore_service.rs");
 	build_file("ValidatorSet", VALIDATOR_SET_ABI, "validator_set.rs");
 	build_file("ValidatorReport", VALIDATOR_REPORT_ABI, "validator_report.rs");
 	build_file("PeerSet", PEER_SET_ABI, "peer_set.rs");

ethcore/native_contracts/generator/src/lib.rs

@@ -46,7 +46,7 @@ pub fn generate_module(struct_name: &str, abi: &str) -> Result<String, Error> {
 	Ok(format!(r##"
 use byteorder::{{BigEndian, ByteOrder}};
 use futures::{{future, Future, IntoFuture}};
-use ethabi::{{Contract, Token, Event}};
+use ethabi::{{Bytes, Contract, Token, Event}};
 use bigint;
 
 type BoxFuture<A, B> = Box<Future<Item = A, Error = B> + Send>;
@@ -96,7 +96,7 @@ fn generate_functions(contract: &Contract) -> Result<String, Error> {
 		let inputs: Vec<_> = function.inputs.iter().map(|i| i.kind.clone()).collect();
 		let outputs: Vec<_> = function.outputs.iter().map(|i| i.kind.clone()).collect();
 
-		let (input_params, to_tokens) = input_params_codegen(&inputs)
+		let (input_params, input_names, to_tokens) = input_params_codegen(&inputs)
 			.map_err(|bad_type| Error::UnsupportedType(name.clone(), bad_type))?;
 
 		let (output_type, decode_outputs) = output_params_codegen(&outputs)
@@ -113,14 +113,14 @@ pub fn {snake_name}<F, U>(&self, call: F, {params}) -> BoxFuture<{output_type},
 	    U: IntoFuture<Item=Vec<u8>, Error=String>,
 		U::Future: Send + 'static
 {{
+	let call_addr = self.address;
+	let call_future = match self.encode_{snake_name}_input({params_names}) {{
+		Ok(call_data) => (call)(call_addr, call_data),
+		Err(e) => return Box::new(future::err(e)),
+	}};
+
 	let function = self.contract.function(r#"{abi_name}"#)
 		.expect("function existence checked at compile-time; qed").clone();
-	let call_addr = self.address;
-
-	let call_future = match function.encode_input(&{to_tokens}) {{
-		Ok(call_data) => (call)(call_addr, call_data),
-		Err(e) => return Box::new(future::err(format!("Error encoding call: {{:?}}", e))),
-	}};
 
 	Box::new(call_future
 		.into_future()
@@ -128,12 +128,22 @@ pub fn {snake_name}<F, U>(&self, call: F, {params}) -> BoxFuture<{output_type},
 		.map(Vec::into_iter)
 		.and_then(|mut outputs| {decode_outputs}))
 }}
+
+/// Encode "{abi_name}" function arguments.
+/// Arguments: {abi_inputs:?}
+pub fn encode_{snake_name}_input(&self, {params}) -> Result<Bytes, String> {{
+	self.contract.function(r#"{abi_name}"#)
+		.expect("function existence checked at compile-time; qed")
+		.encode_input(&{to_tokens})
+		.map_err(|e| format!("Error encoding call: {{:?}}", e))
+}}
 	"##,
 		abi_name = name,
 		abi_inputs = inputs,
 		abi_outputs = outputs,
 		snake_name = snake_name,
 		params = input_params,
+		params_names = input_names,
 		output_type = output_type,
 		to_tokens = to_tokens,
 		decode_outputs = decode_outputs,
@@ -145,15 +155,17 @@ pub fn {snake_name}<F, U>(&self, call: F, {params}) -> BoxFuture<{output_type},
 
 // generate code for params in function signature and turning them into tokens.
 //
-// two pieces of code are generated: the first gives input types for the function signature,
-// and the second gives code to tokenize those inputs.
+// three pieces of code are generated: the first gives input types for the function signature,
+// the second one gives input parameter names to pass to another method,
+// and the third gives code to tokenize those inputs.
 //
 // params of form `param_0: type_0, param_1: type_1, ...`
 // tokenizing code of form `{let mut tokens = Vec::new(); tokens.push({param_X}); tokens }`
 //
 // returns any unsupported param type encountered.
-fn input_params_codegen(inputs: &[ParamType]) -> Result<(String, String), ParamType> {
+fn input_params_codegen(inputs: &[ParamType]) -> Result<(String, String, String), ParamType> {
 	let mut params = String::new();
+	let mut params_names = String::new();
 	let mut to_tokens = "{ let mut tokens = Vec::new();".to_string();
 
 	for (index, param_type) in inputs.iter().enumerate() {
@@ -164,11 +176,13 @@ fn input_params_codegen(inputs: &[ParamType]) -> Result<(String, String), ParamT
 		params.push_str(&format!("{}{}: {}, ",
 			if needs_mut { "mut " } else { "" }, param_name, rust_type));
 
+		params_names.push_str(&format!("{}, ", param_name));
+
 		to_tokens.push_str(&format!("tokens.push({{ {} }});", tokenize_code));
 	}
 
 	to_tokens.push_str(" tokens }");
-	Ok((params, to_tokens))
+	Ok((params, params_names, to_tokens))
 }
 
 // generate code for outputs of the function and detokenizing them.

ethcore/native_contracts/res/secretstore_service.json

@@ -0,0 +1,3 @@
+[
+	{"constant":false,"inputs":[{"name":"serverKeyId","type":"bytes32"},{"name":"serverKeyPublic","type":"bytes"},{"name":"v","type":"uint8"},{"name":"r","type":"bytes32"},{"name":"s","type":"bytes32"}],"name":"serverKeyGenerated","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"}
+]

ethcore/native_contracts/src/lib.rs

@@ -28,6 +28,7 @@ mod registry;
 mod urlhint;
 mod service_transaction;
 mod secretstore_acl_storage;
+mod secretstore_service;
 mod validator_set;
 mod validator_report;
 mod peer_set;
@@ -40,6 +41,7 @@ pub use self::registry::Registry;
 pub use self::urlhint::Urlhint;
 pub use self::service_transaction::ServiceTransactionChecker;
 pub use self::secretstore_acl_storage::SecretStoreAclStorage;
+pub use self::secretstore_service::SecretStoreService;
 pub use self::validator_set::ValidatorSet;
 pub use self::validator_report::ValidatorReport;
 pub use self::peer_set::PeerSet;

ethcore/native_contracts/src/secretstore_service.rs

@@ -0,0 +1,21 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+#![allow(unused_mut, unused_variables, unused_imports)]
+
+//! Secret store service contract.
+
+include!(concat!(env!("OUT_DIR"), "/secretstore_service.rs"));

secret_store/src/lib.rs

@@ -54,12 +54,12 @@ mod types;
 
 mod traits;
 mod acl_storage;
-mod http_listener;
 mod key_server;
 mod key_storage;
 mod serialization;
 mod key_server_set;
 mod node_key_pair;
+mod listener;
 
 use std::sync::Arc;
 use ethcore::client::Client;
@@ -71,8 +71,6 @@ pub use self::node_key_pair::{PlainNodeKeyPair, KeyStoreNodeKeyPair};
 
 /// Start new key server instance
 pub fn start(client: Arc<Client>, self_key_pair: Arc<NodeKeyPair>, config: ServiceConfiguration) -> Result<Box<KeyServer>, Error> {
-	use std::sync::Arc;
-
 	let acl_storage: Arc<acl_storage::AclStorage> = if config.acl_check_enabled {
 			acl_storage::OnChainAclStorage::new(&client)
 		} else {
@@ -80,7 +78,12 @@ pub fn start(client: Arc<Client>, self_key_pair: Arc<NodeKeyPair>, config: Servi
 		};
 	let key_server_set = key_server_set::OnChainKeyServerSet::new(&client, config.cluster_config.nodes.clone())?;
 	let key_storage = Arc::new(key_storage::PersistentKeyStorage::new(&config)?);
-	let key_server = key_server::KeyServerImpl::new(&config.cluster_config, key_server_set, self_key_pair, acl_storage, key_storage)?;
-	let listener = http_listener::KeyServerHttpListener::start(config.listener_address, key_server)?;
+	let key_server = Arc::new(key_server::KeyServerImpl::new(&config.cluster_config, key_server_set, self_key_pair.clone(), acl_storage, key_storage)?);
+	let http_listener = match config.listener_address {
+		Some(listener_address) => Some(listener::http_listener::KeyServerHttpListener::start(listener_address, key_server.clone())?),
+		None => None,
+	};
+	let contract_listener = listener::service_contract_listener::ServiceContractListener::new(&client, key_server.clone(), self_key_pair);
+	let listener = listener::Listener::new(key_server, Some(http_listener), Some(contract_listener));
 	Ok(Box::new(listener))
 }

secret_store/src/listener/http_listener.rs

@@ -25,9 +25,9 @@ use serde::Serialize;
 use serde_json;
 use url::percent_encoding::percent_decode;
 
-use traits::{ServerKeyGenerator, DocumentKeyServer, MessageSigner, KeyServer};
+use traits::KeyServer;
 use serialization::{SerializableEncryptedDocumentKeyShadow, SerializableBytes, SerializablePublic};
-use types::all::{Error, Public, MessageHash, EncryptedMessageSignature, NodeAddress, RequestSignature, ServerKeyId,
+use types::all::{Error, Public, MessageHash, NodeAddress, RequestSignature, ServerKeyId,
 	EncryptedDocumentKey, EncryptedDocumentKeyShadow};
 
 /// Key server http-requests listener. Available requests:
@@ -38,9 +38,9 @@ use types::all::{Error, Public, MessageHash, EncryptedMessageSignature, NodeAddr
 /// To get document key shadow:						GET			/shadow/{server_key_id}/{signature} 
 /// To sign message with server key:				GET			/{server_key_id}/{signature}/{message_hash}
 
-pub struct KeyServerHttpListener<T: KeyServer + 'static> {
-	http_server: Option<HttpListening>,
-	handler: Arc<KeyServerSharedHttpHandler<T>>,
+pub struct KeyServerHttpListener {
+	http_server: HttpListening,
+	_handler: Arc<KeyServerSharedHttpHandler>,
 }
 
 /// Parsed http request
@@ -63,77 +63,44 @@ enum Request {
 }
 
 /// Cloneable http handler
-struct KeyServerHttpHandler<T: KeyServer + 'static> {
-	handler: Arc<KeyServerSharedHttpHandler<T>>,
+struct KeyServerHttpHandler {
+	handler: Arc<KeyServerSharedHttpHandler>,
 }
 
 /// Shared http handler
-struct KeyServerSharedHttpHandler<T: KeyServer + 'static> {
-	key_server: T,
+struct KeyServerSharedHttpHandler {
+	key_server: Arc<KeyServer>,
 }
 
-impl<T> KeyServerHttpListener<T> where T: KeyServer + 'static {
+impl KeyServerHttpListener {
 	/// Start KeyServer http listener
-	pub fn start(listener_address: Option<NodeAddress>, key_server: T) -> Result<Self, Error> {
+	pub fn start(listener_address: NodeAddress, key_server: Arc<KeyServer>) -> Result<Self, Error> {
 		let shared_handler = Arc::new(KeyServerSharedHttpHandler {
 			key_server: key_server,
 		});
 
-		let http_server = listener_address
-			.map(|listener_address| format!("{}:{}", listener_address.address, listener_address.port))
-			.map(|listener_address| HttpServer::http(&listener_address).expect("cannot start HttpServer"))
-			.map(|http_server| http_server.handle(KeyServerHttpHandler {
+		let listener_address = format!("{}:{}", listener_address.address, listener_address.port);
+		let http_server = HttpServer::http(&listener_address).expect("cannot start HttpServer");
+		let http_server = http_server.handle(KeyServerHttpHandler {
 				handler: shared_handler.clone(),
-			}).expect("cannot start HttpServer"));
+			}).expect("cannot start HttpServer");
 
 		let listener = KeyServerHttpListener {
 			http_server: http_server,
-			handler: shared_handler,
+			_handler: shared_handler,
 		};
 		Ok(listener)
 	}
 }
 
-impl<T> KeyServer for KeyServerHttpListener<T> where T: KeyServer + 'static {}
-
-impl<T> ServerKeyGenerator for KeyServerHttpListener<T> where T: KeyServer + 'static {
-	fn generate_key(&self, key_id: &ServerKeyId, signature: &RequestSignature, threshold: usize) -> Result<Public, Error> {
-		self.handler.key_server.generate_key(key_id, signature, threshold)
-	}
-}
-
-impl<T> DocumentKeyServer for KeyServerHttpListener<T> where T: KeyServer + 'static {
-	fn store_document_key(&self, key_id: &ServerKeyId, signature: &RequestSignature, common_point: Public, encrypted_document_key: Public) -> Result<(), Error> {
-		self.handler.key_server.store_document_key(key_id, signature, common_point, encrypted_document_key)
-	}
-
-	fn generate_document_key(&self, key_id: &ServerKeyId, signature: &RequestSignature, threshold: usize) -> Result<EncryptedDocumentKey, Error> {
-		self.handler.key_server.generate_document_key(key_id, signature, threshold)
-	}
-
-	fn restore_document_key(&self, key_id: &ServerKeyId, signature: &RequestSignature) -> Result<EncryptedDocumentKey, Error> {
-		self.handler.key_server.restore_document_key(key_id, signature)
-	}
-
-	fn restore_document_key_shadow(&self, key_id: &ServerKeyId, signature: &RequestSignature) -> Result<EncryptedDocumentKeyShadow, Error> {
-		self.handler.key_server.restore_document_key_shadow(key_id, signature)
-	}
-}
-
-impl <T> MessageSigner for KeyServerHttpListener<T> where T: KeyServer + 'static {
-	fn sign_message(&self, key_id: &ServerKeyId, signature: &RequestSignature, message: MessageHash) -> Result<EncryptedMessageSignature, Error> {
-		self.handler.key_server.sign_message(key_id, signature, message)
-	}
-}
-
-impl<T> Drop for KeyServerHttpListener<T> where T: KeyServer + 'static {
+impl Drop for KeyServerHttpListener {
 	fn drop(&mut self) {
 		// ignore error as we are dropping anyway
 		self.http_server.take().map(|mut s| { let _ = s.close(); });
 	}
 }
 
-impl<T> HttpHandler for KeyServerHttpHandler<T> where T: KeyServer + 'static {
+impl HttpHandler for KeyServerHttpHandler {
 	fn handle(&self, req: HttpRequest, mut res: HttpResponse) {
 		if req.headers.has::<header::Origin>() {
 			warn!(target: "secretstore", "Ignoring {}-request {} with Origin header", req.method, req.uri);
@@ -310,6 +277,7 @@ fn parse_request(method: &HttpMethod, uri_path: &str) -> Request {
 
 #[cfg(test)]
 mod tests {
+	use std::sync::Arc;
 	use hyper::method::Method as HttpMethod;
 	use key_server::tests::DummyKeyServer;
 	use types::all::NodeAddress;
@@ -317,12 +285,12 @@ mod tests {
 
 	#[test]
 	fn http_listener_successfully_drops() {
-		let key_server = DummyKeyServer;
+		let key_server = Arc::new(DummyKeyServer);
 		let address = NodeAddress { address: "127.0.0.1".into(), port: 9000 };
 		let listener = KeyServerHttpListener::start(Some(address), key_server).unwrap();
 		drop(listener);
 	}
-
+ 
 	#[test]
 	fn parse_request_successful() {
 		// POST		/shadow/{server_key_id}/{signature}/{threshold}						=> generate server key

secret_store/src/listener/mod.rs

@@ -0,0 +1,55 @@
+pub mod http_listener;
+pub mod service_contract_listener;
+
+use std::sync::Arc;
+use traits::{ServerKeyGenerator, DocumentKeyServer, MessageSigner, KeyServer};
+use types::all::{Error, Public, MessageHash, EncryptedMessageSignature, RequestSignature, ServerKeyId,
+	EncryptedDocumentKey, EncryptedDocumentKeyShadow};
+
+pub struct Listener {
+	key_server: Arc<KeyServer>,
+	_http: Option<http_listener::KeyServerHttpListener>,
+	_contract: Option<Arc<service_contract_listener::ServiceContractListener>>,
+}
+
+impl Listener {
+	pub fn new(key_server: Arc<KeyServer>, http: Option<http_listener::KeyServerHttpListener>, contract: Option<Arc<service_contract_listener::ServiceContractListener>>) -> Self {
+		Self {
+			key_server: key_server,
+			_http: http,
+			_contract: contract,
+		}
+	}
+}
+
+impl KeyServer for Listener {}
+
+impl ServerKeyGenerator for Listener {
+	fn generate_key(&self, key_id: &ServerKeyId, signature: &RequestSignature, threshold: usize) -> Result<Public, Error> {
+		self.key_server.generate_key(key_id, signature, threshold)
+	}
+}
+
+impl DocumentKeyServer for Listener {
+	fn store_document_key(&self, key_id: &ServerKeyId, signature: &RequestSignature, common_point: Public, encrypted_document_key: Public) -> Result<(), Error> {
+		self.key_server.store_document_key(key_id, signature, common_point, encrypted_document_key)
+	}
+
+	fn generate_document_key(&self, key_id: &ServerKeyId, signature: &RequestSignature, threshold: usize) -> Result<EncryptedDocumentKey, Error> {
+		self.key_server.generate_document_key(key_id, signature, threshold)
+	}
+
+	fn restore_document_key(&self, key_id: &ServerKeyId, signature: &RequestSignature) -> Result<EncryptedDocumentKey, Error> {
+		self.key_server.restore_document_key(key_id, signature)
+	}
+
+	fn restore_document_key_shadow(&self, key_id: &ServerKeyId, signature: &RequestSignature) -> Result<EncryptedDocumentKeyShadow, Error> {
+		self.key_server.restore_document_key_shadow(key_id, signature)
+	}
+}
+
+impl MessageSigner for Listener {
+	fn sign_message(&self, key_id: &ServerKeyId, signature: &RequestSignature, message: MessageHash) -> Result<EncryptedMessageSignature, Error> {
+		self.key_server.sign_message(key_id, signature, message)
+	}
+}

secret_store/src/listener/service_contract_listener.rs

@@ -0,0 +1,138 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::sync::{Arc, Weak};
+use parking_lot::Mutex;	
+use ethcore::filter::Filter;
+use ethcore::client::{Client, BlockChainClient, BlockId, ChainNotify};
+use native_contracts::SecretStoreService;
+use ethkey::{Random, Generator, sign};
+use bytes::Bytes;
+use hash::keccak;
+use bigint::hash::H256;
+use util::Address;
+use {NodeKeyPair, KeyServer};
+
+/// Name of the SecretStore contract in the registry.
+const SERVICE_CONTRACT_REGISTRY_NAME: &'static str = "secretstore_service";
+
+/// Key server has been added to the set.
+const SERVER_KEY_REQUESTED_EVENT_NAME: &'static [u8] = &*b"ServerKeyRequested(bytes32)";
+
+lazy_static! {
+	static ref SERVER_KEY_REQUESTED_EVENT_NAME_HASH: H256 = keccak(SERVER_KEY_REQUESTED_EVENT_NAME);
+}
+
+/// SecretStore <-> Authority connector. Duties:
+/// 1. Listen for new requests on SecretStore contract
+/// 2. Redirects requests for key server
+/// 3. Publishes response on SecretStore contract
+pub struct ServiceContractListener {
+	/// Cached on-chain contract.
+	contract: Mutex<CachedContract>,
+}
+
+/// Cached on-chain Key Server set contract.
+struct CachedContract {
+	/// Blockchain client.
+	client: Weak<Client>,
+	/// Contract.
+	contract: SecretStoreService,
+	/// Contract address.
+	contract_addr: Option<Address>,
+	/// Key server reference.
+	key_server: Arc<KeyServer>,
+	/// This node key pair.
+	self_key_pair: Arc<NodeKeyPair>,
+}
+
+impl ServiceContractListener {
+	pub fn new(client: &Arc<Client>, key_server: Arc<KeyServer>, self_key_pair: Arc<NodeKeyPair>) -> Arc<ServiceContractListener> {
+		let contract = Arc::new(ServiceContractListener {
+			contract: Mutex::new(CachedContract::new(client, key_server, self_key_pair)),
+		});
+		client.add_notify(contract.clone());
+		contract
+	}
+}
+
+impl ChainNotify for ServiceContractListener {
+	fn new_blocks(&self, _imported: Vec<H256>, _invalid: Vec<H256>, enacted: Vec<H256>, _retracted: Vec<H256>, _sealed: Vec<H256>, _proposed: Vec<Bytes>, _duration: u64) {
+		if !enacted.is_empty() {
+			self.contract.lock().update(enacted)
+		}
+	}
+}
+
+impl CachedContract {
+	pub fn new(client: &Arc<Client>, key_server: Arc<KeyServer>, self_key_pair: Arc<NodeKeyPair>) -> Self {
+		CachedContract {
+			client: Arc::downgrade(client),
+			contract: SecretStoreService::new(Default::default()), // we aren't going to call contract => could use default address
+			contract_addr: client.registry_address(SERVICE_CONTRACT_REGISTRY_NAME.to_owned()),
+			key_server: key_server,
+			self_key_pair: self_key_pair,
+		}
+	}
+
+	pub fn update(&mut self, enacted: Vec<H256>) {
+		if let Some(client) = self.client.upgrade() {
+			// update contract address
+			self.contract_addr = client.registry_address(SERVICE_CONTRACT_REGISTRY_NAME.to_owned());
+
+			// check for new key requests.
+			// NOTE: If contract is changed, or unregistered && there are several enacted blocks
+			// in single update call, some requests in old contract can be abandoned (we get contract_address from latest block)
+			// && check for requests in this contract for every enacted block.
+			// The opposite is also true (we can process requests of contract, before it actually becames a SS contract).
+			if let Some(contract_addr) = self.contract_addr.as_ref() {
+				// TODO: in case of reorgs we might process requests for free (maybe wait for several confirmations???) && publish keys without request
+				// TODO: in case of reorgs we might publish keys to forked branch (re-submit transaction???)
+				for block in enacted {
+					let request_logs = client.logs(Filter {
+						from_block: BlockId::Hash(block.clone()),
+						to_block: BlockId::Hash(block),
+						address: Some(vec![contract_addr.clone()]),
+						topics: vec![
+							Some(vec![*SERVER_KEY_REQUESTED_EVENT_NAME_HASH]),
+							None,
+							None,
+							None,
+						],
+						limit: None,
+					});
+
+					// TODO: it actually should queue tasks to separate thread
+					// + separate thread at the beginning should read all requests from contract
+					// and then start processing logs
+					for request in request_logs {
+						// TODO: check if we are selected to process this request
+						let key_id = request.entry.topics[1];
+						let key = Random.generate().unwrap();
+						let signature = sign(key.secret(), &key_id).unwrap();
+						let server_key = self.key_server.generate_key(&key_id, &signature, 0).unwrap();
+println!("=== generated key: {:?}", server_key);
+						// publish generated key
+						let server_key_hash = keccak(server_key);
+						let signed_key = self.self_key_pair.sign(&server_key_hash).unwrap();
+						let transaction_data = self.contract.encode_server_key_generated_input(key_id, server_key.to_vec(), signed_key.v(), signed_key.r().into(), signed_key.s().into()).unwrap();
+						client.transact_contract(contract_addr.clone(), transaction_data).unwrap();
+					}
+				}
+			}
+		}
+	}
+}