diff --git a/ethstore/src/dir/disk.rs b/ethstore/src/dir/disk.rs
index 4a4637850..023db1ac2 100755
--- a/ethstore/src/dir/disk.rs
+++ b/ethstore/src/dir/disk.rs
@@ -90,11 +90,8 @@ impl<T> DiskDirectory<T> where T: KeyFileManager {
 		}
 	}
 
-	/// all accounts found in keys directory
-	fn files(&self) -> Result<HashMap<PathBuf, SafeAccount>, Error> {
-		// it's not done using one iterator cause
-		// there is an issue with rustc and it takes tooo much time to compile
-		let paths = fs::read_dir(&self.path)?
+	fn files(&self) -> Result<Vec<PathBuf>, Error>  {
+		Ok(fs::read_dir(&self.path)?
 			.flat_map(Result::ok)
 			.filter(|entry| {
 				let metadata = entry.metadata().ok();
@@ -102,14 +99,21 @@ impl<T> DiskDirectory<T> where T: KeyFileManager {
 				let name = file_name.to_string_lossy();
 				// filter directories
 				metadata.map_or(false, |m| !m.is_dir()) &&
-				// hidden files
-				!name.starts_with(".") &&
-				// other ignored files
-				!IGNORED_FILES.contains(&&*name)
+					// hidden files
+					!name.starts_with(".") &&
+					// other ignored files
+					!IGNORED_FILES.contains(&&*name)
 			})
 			.map(|entry| entry.path())
-			.collect::<Vec<PathBuf>>();
+			.collect::<Vec<PathBuf>>()
+		)
+	}
 
+	/// all accounts found in keys directory
+	fn files_content(&self) -> Result<HashMap<PathBuf, SafeAccount>, Error> {
+		// it's not done using one iterator cause
+		// there is an issue with rustc and it takes tooo much time to compile
+		let paths = self.files()?;
 		Ok(paths
 			.into_iter()
 			.filter_map(|path| {
@@ -166,7 +170,7 @@ impl<T> DiskDirectory<T> where T: KeyFileManager {
 
 impl<T> KeyDirectory for DiskDirectory<T> where T: KeyFileManager {
 	fn load(&self) -> Result<Vec<SafeAccount>, Error> {
-		let accounts = self.files()?
+		let accounts = self.files_content()?
 			.into_iter()
 			.map(|(_, account)| account)
 			.collect();
@@ -191,7 +195,7 @@ impl<T> KeyDirectory for DiskDirectory<T> where T: KeyFileManager {
 	fn remove(&self, account: &SafeAccount) -> Result<(), Error> {
 		// enumerate all entries in keystore
 		// and find entry with given address
-		let to_remove = self.files()?
+		let to_remove = self.files_content()?
 			.into_iter()
 			.find(|&(_, ref acc)| acc.id == account.id && acc.address == account.address);
 
diff --git a/util/src/sha3.rs b/util/src/sha3.rs
index 45d6a34d5..4d3502313 100644
--- a/util/src/sha3.rs
+++ b/util/src/sha3.rs
@@ -68,6 +68,24 @@ impl<T> Hashable for T where T: AsRef<[u8]> {
 	}
 }
 
+impl<T> Hashable for [T] where T: Hashable {
+	fn sha3(&self) -> H256 {
+		use std::ops::BitXor;
+
+		let mut sha3 = SHA3_EMPTY;
+		for t in self.iter() {
+			sha3 = sha3.bitxor(t.sha3());
+		};
+
+		sha3
+	}
+	// todo: optimize?
+	fn sha3_into(&self, dest: &mut [u8]) {
+		let sha3 = self.sha3();
+		dest.copy_from_slice(&*sha3);
+	}	
+}
+
 /// Calculate SHA3 of given stream.
 pub fn sha3(r: &mut io::BufRead) -> Result<H256, io::Error> {
 	let mut output = [0u8; 32];
@@ -120,4 +138,15 @@ mod tests {
 		// then
 		assert_eq!(format!("{:?}", hash), "68371d7e884c168ae2022c82bd837d51837718a7f7dfb7aa3f753074a35e1d87");
 	}
+
+	#[test]
+	fn should_sha3_strs() {
+		let strs = vec!["abc".to_owned(), "gdc".to_owned()];
+		let hash = strs.sha3();
+		assert_eq!(hash, "b8f24d705171c55892a34c7b863c258f4d47e6864f7a7da45f84155597a3b338".parse().unwrap());
+
+		let strs = vec!["abc".to_owned(), "gdc_".to_owned()];
+		let hash = strs.sha3();
+		assert_eq!(hash, "41bd661b8e02faccad55cdbb28db974dd5c9ae41825b89907fcf25db793b8b09".parse().unwrap());
+	}
 }