diff --git a/ethcore/src/client.rs b/ethcore/src/client.rs
index d9e461024..c7a5ec268 100644
--- a/ethcore/src/client.rs
+++ b/ethcore/src/client.rs
@@ -144,6 +144,9 @@ pub trait BlockChainClient : Sync + Send {
 	fn best_block_header(&self) -> Bytes {
 		self.block_header(BlockId::Hash(self.chain_info().best_block_hash)).unwrap()
 	}
+
+	/// Returns numbers of blocks containing given bloom.
+	fn blocks_with_bloom(&self, bloom: &H2048, from_block: BlockId, to_block: BlockId) -> Option<Vec<BlockNumber>>;
 }
 
 #[derive(Default, Clone, Debug, Eq, PartialEq)]
@@ -358,6 +361,15 @@ impl Client {
 			BlockId::Latest => Some(self.chain.read().unwrap().best_block_hash())
 		}
 	}
+
+	fn block_number(&self, id: BlockId) -> Option<BlockNumber> {
+		match id {
+			BlockId::Number(number) => Some(number),
+			BlockId::Hash(ref hash) => self.chain.read().unwrap().block_number(hash),
+			BlockId::Earliest => Some(0),
+			BlockId::Latest => Some(self.chain.read().unwrap().best_block_number())
+		}
+	}
 }
 
 impl BlockChainClient for Client {
@@ -450,6 +462,13 @@ impl BlockChainClient for Client {
 			best_block_number: From::from(chain.best_block_number())
 		}
 	}
+
+	fn blocks_with_bloom(&self, bloom: &H2048, from_block: BlockId, to_block: BlockId) -> Option<Vec<BlockNumber>> {
+		match (self.block_number(from_block), self.block_number(to_block)) {
+			(Some(from), Some(to)) => Some(self.chain.read().unwrap().blocks_with_bloom(bloom, from, to)),
+			_ => None
+		}
+	}
 }
 
 impl MayPanic for Client {
diff --git a/rpc/src/v1/types/filter.rs b/rpc/src/v1/types/filter.rs
index 9b21cf8e7..cac1f7ef9 100644
--- a/rpc/src/v1/types/filter.rs
+++ b/rpc/src/v1/types/filter.rs
@@ -18,40 +18,95 @@ use serde::{Deserialize, Deserializer, Error};
 use serde_json::value;
 use jsonrpc_core::Value;
 use util::hash::*;
+use util::sha3::*;
 use v1::types::BlockNumber;
 
 #[derive(Debug, PartialEq)]
-pub enum Topic {
-	Single(H256),
-	Multiple(Vec<H256>),
+pub enum VariadicValue<T> where T: Deserialize {
+	Single(T),
+	Multiple(Vec<T>),
 	Null
 }
 
-impl Deserialize for Topic {
-	fn deserialize<D>(deserializer: &mut D) -> Result<Topic, D::Error>
+impl<T> Deserialize for VariadicValue<T> where T: Deserialize {
+	fn deserialize<D>(deserializer: &mut D) -> Result<VariadicValue<T>, D::Error>
 	where D: Deserializer {
 		let v = try!(Value::deserialize(deserializer));
 
 		if v.is_null() {
-			return Ok(Topic::Null);
+			return Ok(VariadicValue::Null);
 		}
 
-		Deserialize::deserialize(&mut value::Deserializer::new(v.clone())).map(Topic::Single)
-			.or_else(|_| Deserialize::deserialize(&mut value::Deserializer::new(v.clone())).map(Topic::Multiple))
+		Deserialize::deserialize(&mut value::Deserializer::new(v.clone())).map(VariadicValue::Single)
+			.or_else(|_| Deserialize::deserialize(&mut value::Deserializer::new(v.clone())).map(VariadicValue::Multiple))
 			.map_err(|_| Error::syntax("")) // unreachable, but types must match
 	}
 }
 
+pub type FilterAddress = VariadicValue<Address>;
+pub type Topic = VariadicValue<H256>;
+
 #[derive(Debug, PartialEq, Deserialize)]
 pub struct Filter {
 	#[serde(rename="fromBlock")]
 	pub from_block: Option<BlockNumber>,
 	#[serde(rename="toBlock")]
 	pub to_block: Option<BlockNumber>,
-	pub address: Option<Address>,
+	pub address: Option<FilterAddress>,
 	pub topics: Option<Vec<Topic>>
 }
 
+impl Filter {
+	/// Returns combinations of each of address topic.	
+	pub fn bloom_possibilities(&self) -> Vec<H2048> {
+		let blooms = match self.address {
+			Some(VariadicValue::Single(ref address)) => {
+				let mut bloom = H2048::new();
+				bloom.shift_bloomed(&address.sha3());
+				vec![bloom]
+			},
+			Some(VariadicValue::Multiple(ref addresses)) => {
+				addresses.iter().map(|ref address| {
+					let mut bloom = H2048::new();
+					bloom.shift_bloomed(&address.sha3());
+					bloom
+				}).collect()
+			},
+			_ => vec![H2048::new()]
+		};
+
+		match self.topics {
+			None => blooms,
+			Some(ref topics) => blooms.into_iter().map(|bloom| {
+				//for topic in topics {
+					//match topic {
+						//VariadicValue::Single => {
+							//bloom.shift_bloomed(&topic.sha3());
+							//bloom
+						//}
+					//}
+				//}
+			}).collect()
+		}
+		//self.address.as_ref().map(|a| match *a {
+			//VariadicValue::Single(ref address) => {
+				//let mut bloom = H2048::new();
+				//bloom.shift_bloomed(&address.sha3());
+				//vec![bloom]
+			//},
+			//VariadicValue::Multiple(ref addresses) => {
+				//addresses.iter().map(|ref address| {
+					//let mut bloom = H2048::new();
+					//bloom.shift_bloomed(&address.sha3());
+					//bloom
+				//}).collect()
+			//},
+			//VariadicValue::Null => vec![H2048::new()]
+		//}.into_iter().map(|bloom| match self. {
+		//}).unwrap_or_else(Vec::new)
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use serde_json;
@@ -65,9 +120,9 @@ mod tests {
 		let s = r#"["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", null, ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", "0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc"]]"#;
 		let deserialized: Vec<Topic> = serde_json::from_str(s).unwrap();
 		assert_eq!(deserialized, vec![
-				   Topic::Single(H256::from_str("000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b").unwrap()),
-				   Topic::Null,
-				   Topic::Multiple(vec![
+				   VariadicValue::Single(H256::from_str("000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b").unwrap()),
+				   VariadicValue::Null,
+				   VariadicValue::Multiple(vec![
 								   H256::from_str("000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b").unwrap(),
 								   H256::from_str("0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc").unwrap()
 				   ])