Implement priority message

Author: HoOngEe

core/src/consensus/sortition/mod.rs

@@ -16,3 +16,4 @@
 
 mod binom_cdf;
 mod lot;
+mod priority_message;

core/src/consensus/sortition/priority_message.rs

@@ -0,0 +1,56 @@
+// Copyright 2019 Kodebox, Inc.
+// This file is part of CodeChain.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use ccrypto::sha256;
+use ckey::Public;
+use primitives::H256;
+use vrf::openssl::{Error as VrfError, ECVRF};
+use vrf::VRF;
+
+pub type Priority = H256;
+
+pub struct PriorityMessage {
+    msg_hash: H256,
+    priority: Priority,
+    vrf_hash: Vec<u8>,
+    vrf_proof: Vec<u8>,
+    sub_user_index: u64,
+    signer_index: usize,
+}
+
+impl PriorityMessage {
+    pub fn signer_index(&self) -> usize {
+        self.signer_index
+    }
+
+    fn verify_vrf_hash(&self, signer_public: &Public, vrf_inst: &mut ECVRF) -> Result<bool, VrfError> {
+        let verified_hash = vrf_inst.verify(signer_public, &self.vrf_proof, &*self.msg_hash)?;
+        Ok(verified_hash == self.vrf_hash)
+    }
+
+    pub fn verify(&self, signer_public: &Public, vrf_inst: &mut ECVRF) -> Result<bool, VrfError> {
+        let vrf_verification_result = self.verify_vrf_hash(signer_public, vrf_inst)?;
+        if vrf_verification_result {
+            let sub_user_idx_vec = self.sub_user_index.to_be_bytes();
+            let concatenated = [&self.vrf_hash[..], &sub_user_idx_vec[..]].concat();
+
+            let expected_priority = sha256(&concatenated);
+            Ok(expected_priority == self.priority)
+        } else {
+            Ok(false)
+        }
+    }
+}

core/src/lib.rs

@@ -55,6 +55,7 @@ extern crate snap;
 extern crate statrs;
 extern crate table;
 extern crate util_error;
+extern crate vrf;
 #[macro_use]
 extern crate log;
 extern crate core;