xmr: fix scan long encrypted amount

networks/monero/wallet/src/lib.rs

@@ -137,15 +137,13 @@ impl SharedKeyDerivations {
 
   fn decrypt(&self, enc_amount: &EncryptedAmount) -> Commitment {
     match enc_amount {
-      // TODO: Add a test vector for this
       EncryptedAmount::Original { mask, amount } => {
-        let mask_shared_sec = keccak256(self.shared_key.as_bytes());
-        let mask =
-          Scalar::from_bytes_mod_order(*mask) - Scalar::from_bytes_mod_order(mask_shared_sec);
+        let mask_shared_sec_scalar = keccak256_to_scalar(self.shared_key.as_bytes());
+        let amount_shared_sec_scalar = keccak256_to_scalar(mask_shared_sec_scalar.as_bytes());
+
+        let mask = Scalar::from_bytes_mod_order(*mask) - mask_shared_sec_scalar;
+        let amount_scalar = Scalar::from_bytes_mod_order(*amount) - amount_shared_sec_scalar;
 
-        let amount_shared_sec = keccak256(mask_shared_sec);
-        let amount_scalar =
-          Scalar::from_bytes_mod_order(*amount) - Scalar::from_bytes_mod_order(amount_shared_sec);
         // d2b from rctTypes.cpp
         let amount = u64::from_le_bytes(amount_scalar.to_bytes()[0 .. 8].try_into().unwrap());
 

networks/monero/wallet/src/tests/mod.rs

@@ -1 +1,2 @@
 mod extra;
+mod scan;

networks/monero/wallet/src/tests/scan.rs

@@ -0,0 +1,168 @@
+use monero_rpc::ScannableBlock;
+use crate::{
+  transaction::{Pruned, Transaction},
+  block::Block,
+  ViewPair, Scanner, WalletOutput,
+  output::{AbsoluteId, RelativeId, OutputData, Metadata},
+  Commitment,
+  PaymentId::Encrypted,
+  transaction::Timelock,
+  ringct::EncryptedAmount,
+};
+use zeroize::Zeroizing;
+use curve25519_dalek::{Scalar, constants::ED25519_BASEPOINT_TABLE, edwards::CompressedEdwardsY};
+
+const SPEND_KEY: &str = "ccf0ea10e1ea64354f42fa710c2b318e581969cf49046d809d1f0aadb3fc7a02";
+const VIEW_KEY: &str = "a28b4b2085592881df94ee95da332c16b5bb773eb8bb74730208cbb236c73806";
+
+#[rustfmt::skip]
+const PRUNED_TX_WITH_LONG_ENCRYPTED_AMOUNT: &str = "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";
+
+#[rustfmt::skip]
+const BLOCK: &str = "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";
+
+const OUTPUT_INDEX_FOR_FIRST_RINGCT_OUTPUT: u64 = 0; // note the miner tx is a v1 tx
+
+fn wallet_output0() -> WalletOutput {
+  WalletOutput {
+    absolute_id: AbsoluteId {
+      transaction: hex::decode("b74773bbea995079805398052da9b69244bda034b089b50e4d9151dedb59a12f")
+        .unwrap()
+        .try_into()
+        .unwrap(),
+      index_in_transaction: 0,
+    },
+    relative_id: RelativeId { index_on_blockchain: OUTPUT_INDEX_FOR_FIRST_RINGCT_OUTPUT },
+    data: OutputData {
+      key: CompressedEdwardsY(
+        hex::decode("ee8ca293511571c0005e1c144e49d09b8ff03046dbafb3e064a34cb9fc1994b6")
+          .unwrap()
+          .try_into()
+          .unwrap(),
+      )
+      .decompress()
+      .unwrap(),
+      key_offset: Scalar::from_canonical_bytes(
+        hex::decode("f1d21a76ea0bb228fbc5f0dece0597a8ffb59de7a04b29f70b7c0310446ea905")
+          .unwrap()
+          .try_into()
+          .unwrap(),
+      )
+      .unwrap(),
+      commitment: Commitment {
+        amount: 10000,
+        mask: Scalar::from_canonical_bytes(
+          hex::decode("05c2f142aaf3054cbff0a022f6c7cb75403fd92af0f9441c072ade3f273f7706")
+            .unwrap()
+            .try_into()
+            .unwrap(),
+        )
+        .unwrap(),
+      },
+    },
+    metadata: Metadata {
+      additional_timelock: Timelock::None,
+      subaddress: None,
+      payment_id: Some(Encrypted([0, 0, 0, 0, 0, 0, 0, 0])),
+      arbitrary_data: [].to_vec(),
+    },
+  }
+}
+
+fn wallet_output1() -> WalletOutput {
+  WalletOutput {
+    absolute_id: AbsoluteId {
+      transaction: hex::decode("b74773bbea995079805398052da9b69244bda034b089b50e4d9151dedb59a12f")
+        .unwrap()
+        .try_into()
+        .unwrap(),
+      index_in_transaction: 1,
+    },
+    relative_id: RelativeId { index_on_blockchain: OUTPUT_INDEX_FOR_FIRST_RINGCT_OUTPUT + 1 },
+    data: OutputData {
+      key: CompressedEdwardsY(
+        hex::decode("9e2e5cd08c8681dbcf2ce66071467e835f7e86613fbfed3c4fb170127b94e107")
+          .unwrap()
+          .try_into()
+          .unwrap(),
+      )
+      .decompress()
+      .unwrap(),
+      key_offset: Scalar::from_canonical_bytes(
+        hex::decode("c5189738c1cb40e68d464f1a1848a85f6ab2c09652a31849213dc0fefd212806")
+          .unwrap()
+          .try_into()
+          .unwrap(),
+      )
+      .unwrap(),
+      commitment: Commitment {
+        amount: 10000,
+        mask: Scalar::from_canonical_bytes(
+          hex::decode("c8922ce32cb2bf454a6b77bc91423ba7a18412b71fa39a97a2a743c1fe0bad04")
+            .unwrap()
+            .try_into()
+            .unwrap(),
+        )
+        .unwrap(),
+      },
+    },
+    metadata: Metadata {
+      additional_timelock: Timelock::None,
+      subaddress: None,
+      payment_id: Some(Encrypted([0, 0, 0, 0, 0, 0, 0, 0])),
+      arbitrary_data: [].to_vec(),
+    },
+  }
+}
+
+#[test]
+fn scan_long_encrypted_amount() {
+  // Parse strings
+  let spend_key_buf = hex::decode(SPEND_KEY).unwrap();
+  let spend_key =
+    Zeroizing::new(Scalar::from_canonical_bytes(spend_key_buf.try_into().unwrap()).unwrap());
+
+  let view_key_buf = hex::decode(VIEW_KEY).unwrap();
+  let view_key =
+    Zeroizing::new(Scalar::from_canonical_bytes(view_key_buf.try_into().unwrap()).unwrap());
+
+  let tx_buf = hex::decode(PRUNED_TX_WITH_LONG_ENCRYPTED_AMOUNT).unwrap();
+  let tx = Transaction::<Pruned>::read::<&[u8]>(&mut tx_buf.as_ref()).unwrap();
+
+  let block_buf = hex::decode(BLOCK).unwrap();
+  let block = Block::read::<&[u8]>(&mut block_buf.as_ref()).unwrap();
+
+  // Confirm tx has long form encrypted amounts
+  match &tx {
+    Transaction::V2 { prefix: _, proofs } => {
+      let proofs = proofs.clone().unwrap();
+      assert_eq!(proofs.base.encrypted_amounts.len(), 2);
+      assert!(proofs
+        .base
+        .encrypted_amounts
+        .iter()
+        .all(|o| matches!(o, EncryptedAmount::Original { .. })));
+    }
+    _ => panic!("Unexpected tx version"),
+  };
+
+  // Prepare scanner
+  let spend_pub = &*spend_key * ED25519_BASEPOINT_TABLE;
+  let view: ViewPair = ViewPair::new(spend_pub, view_key).unwrap();
+  let mut scanner = Scanner::new(view);
+
+  // Prepare scannable block
+  let txs: Vec<Transaction<Pruned>> = vec![tx];
+  let scannable_block = ScannableBlock {
+    block,
+    transactions: txs,
+    output_index_for_first_ringct_output: Some(OUTPUT_INDEX_FOR_FIRST_RINGCT_OUTPUT),
+  };
+
+  // Scan the block
+  let outputs = scanner.scan(scannable_block).unwrap().not_additionally_locked();
+
+  assert_eq!(outputs.len(), 2);
+  assert_eq!(outputs[0], wallet_output0());
+  assert_eq!(outputs[1], wallet_output1());
+}