diff --git a/json/src/hash.rs b/json/src/hash.rs
index 9aad33115..b09c596f1 100644
--- a/json/src/hash.rs
+++ b/json/src/hash.rs
@@ -20,7 +20,7 @@ use std::str::FromStr;
 use serde::{Deserialize, Deserializer, Serialize, Serializer, Error};
 use serde::de::Visitor;
 use rustc_serialize::hex::ToHex;
-use util::hash::{H64 as Hash64, H160 as Hash160, H256 as Hash256, H2048 as Hash2048};
+use util::hash::{H64 as Hash64, H160 as Hash160, H256 as Hash256, H520 as Hash520, H2048 as Hash2048};
 
 
 macro_rules! impl_hash {
@@ -87,6 +87,7 @@ macro_rules! impl_hash {
 impl_hash!(H64, Hash64);
 impl_hash!(Address, Hash160);
 impl_hash!(H256, Hash256);
+impl_hash!(H520, Hash520);
 impl_hash!(Bloom, Hash2048);
 
 #[cfg(test)]
diff --git a/json/src/spec/mod.rs b/json/src/spec/mod.rs
index 19b9974d9..dcd1f3361 100644
--- a/json/src/spec/mod.rs
+++ b/json/src/spec/mod.rs
@@ -33,7 +33,7 @@ pub use self::builtin::{Builtin, Pricing, Linear};
 pub use self::genesis::Genesis;
 pub use self::params::Params;
 pub use self::spec::Spec;
-pub use self::seal::{Seal, Ethereum, Generic};
+pub use self::seal::{Seal, Ethereum, AuthorityRoundSeal};
 pub use self::engine::Engine;
 pub use self::state::State;
 pub use self::ethash::{Ethash, EthashParams};
diff --git a/json/src/spec/seal.rs b/json/src/spec/seal.rs
index eba75840a..d586ed501 100644
--- a/json/src/spec/seal.rs
+++ b/json/src/spec/seal.rs
@@ -16,7 +16,8 @@
 
 //! Spec seal deserialization.
 
-use hash::{H64, H256};
+use hash::*;
+use uint::Uint;
 use bytes::Bytes;
 
 /// Ethereum seal.
@@ -29,11 +30,13 @@ pub struct Ethereum {
 	pub mix_hash: H256,
 }
 
-/// Generic seal.
+/// AuthorityRound seal.
 #[derive(Debug, PartialEq, Deserialize)]
-pub struct Generic {
-	/// Seal rlp.
-	pub rlp: Bytes,
+pub struct AuthorityRoundSeal {
+	/// Seal step.
+	pub step: Uint,
+	/// Seal signature.
+	pub signature: H520,
 }
 
 /// Seal variants.
@@ -42,9 +45,12 @@ pub enum Seal {
 	/// Ethereum seal.
 	#[serde(rename="ethereum")]
 	Ethereum(Ethereum),
+	/// AuthorityRound seal.
+	#[serde(rename="authority_round")]
+	AuthorityRound(AuthorityRoundSeal),
 	/// Generic seal.
 	#[serde(rename="generic")]
-	Generic(Generic),
+	Generic(Bytes),
 }
 
 #[cfg(test)]
@@ -53,15 +59,18 @@ mod tests {
 	use spec::Seal;
 
 	#[test]
-	fn builtin_deserialization() {
+	fn seal_deserialization() {
 		let s = r#"[{
 			"ethereum": {
 				"nonce": "0x0000000000000042",
 				"mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
 			}
 		},{
-			"generic": {
-				"rlp": "0xe011bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa"
+			"generic": "0xe011bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa"
+		},{
+			"authority_round": {
+				"step": "0x0",
+				"signature": "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
 			}
 		}]"#;
 		let _deserialized: Vec<Seal> = serde_json::from_str(s).unwrap();