diff --git a/substrate/README.adoc b/substrate/README.adoc
index 4d8bc466f5..48ccc3ef91 100644
--- a/substrate/README.adoc
+++ b/substrate/README.adoc
@@ -406,11 +406,12 @@ https://github.com/paritytech/substrate/blob/master/core/primitives/src/crypto.r
 user can declare any key type.
 
 ```
-curl -H 'Content-Type: application/json' --data '{ "jsonrpc":"2.0", "method":"author_insertKey", "params":["KEY_TYPE", "SEED"],"id":1 }' localhost:9933
+curl -H 'Content-Type: application/json' --data '{ "jsonrpc":"2.0", "method":"author_insertKey", "params":["KEY_TYPE", "SEED", "PUBLIC"],"id":1 }' localhost:9933
 ```
 
 `KEY_TYPE` - needs to be replaced with the 4-character key type identifier.
 `SEED` - is the seed of the key.
+`PUBLIC` - public key for the given key.
 
 == Documentation
 
diff --git a/substrate/core/rpc/api/src/author/mod.rs b/substrate/core/rpc/api/src/author/mod.rs
index 3d5698880a..e8314c5c5f 100644
--- a/substrate/core/rpc/api/src/author/mod.rs
+++ b/substrate/core/rpc/api/src/author/mod.rs
@@ -44,8 +44,8 @@ pub trait AuthorApi<Hash, BlockHash> {
 	fn insert_key(&self,
 		key_type: String,
 		suri: String,
-		maybe_public: Option<Bytes>
-	) -> Result<Bytes>;
+		public: Bytes,
+	) -> Result<()>;
 
 	/// Generate new session keys and returns the corresponding public keys.
 	#[rpc(name = "author_rotateKeys")]
diff --git a/substrate/core/rpc/src/author/mod.rs b/substrate/core/rpc/src/author/mod.rs
index 4c72a96023..78a8ff804f 100644
--- a/substrate/core/rpc/src/author/mod.rs
+++ b/substrate/core/rpc/src/author/mod.rs
@@ -94,29 +94,14 @@ impl<B, E, P, RA> AuthorApi<ExHash<P>, BlockHash<P>> for Author<B, E, P, RA> whe
 		&self,
 		key_type: String,
 		suri: String,
-		maybe_public: Option<Bytes>,
-	) -> Result<Bytes> {
+		public: Bytes,
+	) -> Result<()> {
 		let key_type = key_type.as_str().try_into().map_err(|_| Error::BadKeyType)?;
 		let mut keystore = self.keystore.write();
 		let maybe_password = keystore.password();
-		let public = match maybe_public {
-			Some(public) => public.0,
-			None => {
-				let maybe_public = match key_type {
-					key_types::BABE | key_types::SR25519 =>
-						sr25519::Pair::from_string(&suri, maybe_password)
-							.map(|pair| pair.public().to_raw_vec()),
-					key_types::GRANDPA | key_types::ED25519 =>
-						ed25519::Pair::from_string(&suri, maybe_password)
-							.map(|pair| pair.public().to_raw_vec()),
-					_ => Err(Error::UnsupportedKeyType)?,
-				};
-				maybe_public.map_err(|_| Error::BadSeedPhrase)?
-			}
-		};
 		keystore.insert_unknown(key_type, &suri, &public[..])
 			.map_err(|_| Error::KeyStoreUnavailable)?;
-		Ok(public.into())
+		Ok(())
 	}
 
 	fn rotate_keys(&self) -> Result<Bytes> {
diff --git a/substrate/core/rpc/src/author/tests.rs b/substrate/core/rpc/src/author/tests.rs
index e7cf84c927..8e6243f40e 100644
--- a/substrate/core/rpc/src/author/tests.rs
+++ b/substrate/core/rpc/src/author/tests.rs
@@ -200,7 +200,7 @@ fn should_insert_key() {
 	p.insert_key(
 		String::from_utf8(key_types::ED25519.0.to_vec()).expect("Keytype is a valid string"),
 		suri.to_string(),
-		Some(key_pair.public().0.to_vec().into()),
+		key_pair.public().0.to_vec().into(),
 	).expect("Insert key");
 
 	let store_key_pair = keystore.read()