[consensus/stx] verify stx

proof/tx.zk

@@ -39,7 +39,7 @@ circuit "tx" {
         PREFIX_SN = witness_base(6);
         # coin (1) pk/public key
         c1_pk = poseidon_hash(PREFIX_PK, c1_root_sk);
-        constrain_instance(c1_pk);
+        #constrain_instance(c1_pk);
         # coin (1) cm/commitment
         c1_cm_msg = poseidon_hash(PREFIX_CM, c1_pk, c1_value, c1_rho);
         c1_cm_v = ec_mul_base(c1_cm_msg, NULLIFIER_K);

src/consensus/leadcoin.rs

@@ -32,11 +32,11 @@ use rand::rngs::OsRng;
 
 use super::constants::{EPOCH_LENGTH};
 use crate::{
-    consensus::{TxRcpt,EncryptedTxRcpt},
+    consensus::{TxRcpt,EncryptedTxRcpt,TransferStx},
     crypto::{proof::ProvingKey, Proof},
     zk::{vm::ZkCircuit, vm_stack::Witness},
     zkas::ZkBinary,
-    Result,
+    Result, Error,
 };
 use darkfi_serial::{Encodable, Decodable, SerialDecodable, SerialEncodable};
 
@@ -50,21 +50,7 @@ pub const PREFIX_CM: u64 = 4;
 pub const PREFIX_PK: u64 = 5;
 pub const PREFIX_SN: u64 = 6;
 
-#[derive(Debug, Clone, SerialDecodable, SerialEncodable)]
-pub struct TransferStx {
-    /// coin3_commitment in zk
-    pub change_coin_commitment: pallas::Point,
-    /// coin4_commitment in zk
-    pub transfered_coin_commitment: pallas::Point,
-    /// nullifiers coin1_nullifier
-    pub nullifier: pallas::Base,
-    /// sk coin pos
-    pub tau: pallas::Base,
-    /// root to coin's commitments
-    pub root: MerkleNode,
-    /// transfer proof
-    pub proof: Proof,
-}
+
 
 // TODO: Unify item names with the names in the ZK proof (those are more descriptive)
 /// Structure representing the consensus leader coin
@@ -438,6 +424,9 @@ impl LeadCoin {
         let cm4_msg = poseidon_hash(cm4_msg_in);
         let cm4 = pedersen_commitment_base(cm4_msg, transfered_coin.opening);
         let tx  = TransferStx {
+            coin_commitment: self.coin1_commitment,
+            coin_pk: self.pk(),
+            coin_root_sk: self.coin1_sk_root,
             change_coin_commitment: cm3,
             transfered_coin_commitment: cm4,
             nullifier: self.sn,

src/consensus/mod.rs

@@ -54,9 +54,14 @@ pub mod utils;
 /// Wallet functions
 pub mod wallet;
 
-/// received transaction.
+/// transfered tx proof with public inputs.
+pub mod stx;
+pub use stx::TransferStx;
+
+/// encrypted receipient coin info
 pub mod rcpt;
 pub use rcpt::{TxRcpt,EncryptedTxRcpt};
 
+/// transfer transaction
 pub mod tx;
 pub use tx::Tx;

src/consensus/rcpt.rs

@@ -1,3 +1,22 @@
+/* This file is part of DarkFi (https://dark.fi)
+ *
+ * Copyright (C) 2020-2022 Dyne.org foundation
+ *
+ * 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 darkfi_sdk::{
     crypto::{
         keypair::{PublicKey},

src/consensus/stx.rs

@@ -0,0 +1,80 @@
+/* This file is part of DarkFi (https://dark.fi)
+ *
+ * Copyright (C) 2020-2022 Dyne.org foundation
+ *
+ * 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 darkfi_sdk::{
+    pasta::{arithmetic::CurveAffine, group::Curve, pallas},
+    crypto::MerkleNode,
+};
+
+use crate::{
+    crypto::{proof::VerifyingKey, Proof},
+    Result, Error,
+};
+use darkfi_serial::{Encodable, Decodable, SerialDecodable, SerialEncodable};
+
+#[derive(Debug, Clone, SerialDecodable, SerialEncodable)]
+pub struct TransferStx {
+    /// sender's coin, or coin1_commitment in zk
+    pub coin_commitment: pallas::Point,
+    /// sender's coin pk
+    pub coin_pk: pallas::Base,
+    /// sender's coin sk's root
+    pub coin_root_sk: MerkleNode,
+    /// coin3_commitment in zk
+    pub change_coin_commitment: pallas::Point,
+    /// coin4_commitment in zk
+    pub transfered_coin_commitment: pallas::Point,
+    /// nullifiers coin1_nullifier
+    pub nullifier: pallas::Base,
+    /// sk coin pos
+    pub tau: pallas::Base,
+    /// root to coin's commitments
+    pub root: MerkleNode,
+    /// transfer proof
+    pub proof: Proof,
+}
+
+impl TransferStx {
+
+    /// verify the transfer proof.
+    pub fn verify(&self, vk: VerifyingKey)  -> Result<()> {
+        if let Err(e) = self.proof.verify(&vk, &self.public_inputs()) {
+            return Err(Error::TransferTxVerification)
+        }
+        Ok(())
+    }
+
+    /// arrange public inputs from Stxfer
+    pub fn public_inputs(&self) -> Vec<pallas::Base> {
+        let cm1 = self.coin_commitment.to_affine().coordinates().unwrap();
+        let cm3 = self.change_coin_commitment.to_affine().coordinates().unwrap();
+        let cm4 = self.transfered_coin_commitment.to_affine().coordinates().unwrap();
+        vec![
+            self.coin_pk,
+            *cm1.x(),
+            *cm1.y(),
+            *cm3.x(),
+            *cm3.y(),
+            *cm4.x(),
+            *cm4.y(),
+            self.root.inner(),
+            self.coin_root_sk.inner(),
+            self.nullifier,
+        ]
+    }
+}

src/consensus/tx.rs

@@ -1,6 +1,6 @@
 use darkfi_serial::{Encodable, Decodable, SerialDecodable, SerialEncodable};
 use crate::{
-    consensus::{EncryptedTxRcpt, leadcoin::TransferStx},
+    consensus::{EncryptedTxRcpt, TransferStx},
 };
 
 /// transfer transaction

src/error.rs

@@ -241,6 +241,9 @@ pub enum Error {
     #[error("Proposal contains missmatched headers")]
     ProposalHeadersMissmatchError,
 
+    #[error("unable to verify transfer transaction")]
+    TransferTxVerification,
+
     // ===============
     // Database errors
     // ===============