Add TreeHash trait to all types and structs

eth2/utils/bls/src/secret_key.rs

@@ -1,5 +1,5 @@
 use bls_aggregates::{DecodeError as BlsDecodeError, SecretKey as RawSecretKey};
-use ssz::{decode_ssz_list, Decodable, DecodeError, Encodable, SszStream};
+use ssz::{decode_ssz_list, Decodable, DecodeError, Encodable, SszStream, TreeHash};
 
 /// A single BLS signature.
 ///
@@ -40,6 +40,12 @@ impl Decodable for SecretKey {
     }
 }
 
+impl TreeHash for SecretKey {
+    fn hash_tree_root(&self) -> Vec<u8> {
+        self.0.as_bytes().clone()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::super::ssz::ssz_encode;