diff --git a/ethcore/src/types/security_level.rs b/ethcore/src/types/security_level.rs
new file mode 100644
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+++ b/ethcore/src/types/security_level.rs
@@ -0,0 +1,28 @@
+// Copyright 2015, 2016 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/>.
+
+//! Indication of how secure the chain is.
+
+/// Indication of how secure the chain is.
+#[derive(Debug, PartialEq, Copy, Clone, Hash, Eq, Binary)]
+pub enum SecurityLevel {
+	/// Chain was synced through manually evaluating all transactions from genesis.
+	Full,
+	/// All blocks are known to have a valid PoW from genesis.
+	Continuous,
+	/// Some headers (the argument) are known to have a valid PoW from genesis.
+	Light(u64),
+}