Put in the test checking the public key from the output transaction

This commit implements checking the public key from the output
transaction against the ripemd160 of the sha256 of the target address.

Furhter this commit fixes the clippy warnings that appeared in the
last commit

wasm/wasm_source/Cargo.toml

@@ -42,6 +42,7 @@ wee_alloc = "0.4.5"
 getrandom = { version = "0.2", features = ["custom"] }
 masp_proofs = { git = "https://github.com/anoma/masp", rev = "bee40fc465f6afbd10558d12fe96eb1742eee45c", optional = true }
 masp_primitives = { git = "https://github.com/anoma/masp", rev = "bee40fc465f6afbd10558d12fe96eb1742eee45c", optional = true }
+ripemd160 = "0.9.1"
 
 [dev-dependencies]
 namada = {path = "../../shared"}

wasm/wasm_source/src/vp_masp.rs

@@ -1,11 +1,13 @@
 use std::cmp::Ordering;
 
 use masp_primitives::asset_type::AssetType;
-use masp_primitives::transaction::components::{Amount, TxIn, TxOut};
+use masp_primitives::legacy::TransparentAddress::{PublicKey, Script};
+use masp_primitives::transaction::components::{Amount, TxOut};
 /// Multi-asset shielded pool VP.
 use namada_vp_prelude::address::masp;
 use namada_vp_prelude::storage::Epoch;
 use namada_vp_prelude::*;
+use ripemd160::{Digest, Ripemd160};
 
 /// Generates the current asset type given the current epoch and an
 /// unique token address
@@ -98,8 +100,8 @@ fn validate_tx(
         // The following boundary conditions must be satisfied
         // 1. One transparent input
         // 2. Zero transparent output
-        // 3. Asset type must be properly derived
-        // 4. Value from the input must be the same as the transfer
+        // 3. the transparent transaction value pool's amount must equal the
+        // containing wrapper transaction's fee amount
         if transfer.source != masp() {
             // Satisfies 1.
             if shielded_tx.vin.len() != 1 {
@@ -112,7 +114,7 @@ fn validate_tx(
             }
 
             // Satisfies 2.
-            if shielded_tx.vout.len() != 0 {
+            if !shielded_tx.vout.is_empty() {
                 debug_log!(
                     "Transparent output to a transaction from the masp must \
                      be 0 but is {}",
@@ -121,10 +123,6 @@ fn validate_tx(
                 return reject();
             }
 
-            // Can not Satisfy 3. nor 4. due to TxIn having
-            // insufficient data
-            let _tx_in: &TxIn = &shielded_tx.vin[0];
-
             // Note that the asset type is timestamped so shields
             // where the shielded value has an incorrect timestamp
             // are automatically rejected
@@ -147,7 +145,7 @@ fn validate_tx(
         // 5. Public key must be the hash of the target
         if transfer.target != masp() {
             // Satisfies 1.
-            if shielded_tx.vin.len() != 0 {
+            if !shielded_tx.vin.is_empty() {
                 debug_log!(
                     "Transparent input to a transaction to the masp must be 0 \
                      but is {}",
@@ -192,8 +190,27 @@ fn validate_tx(
             // Non-masp destinations subtract from transparent tx pool
             transparent_tx_pool -= transp_amt;
 
-            // Can not Satisfy 5. as TxOut lacks an accompanying
-            // Public key.
+            // Satisfies 5.
+            match out.script_pubkey.address() {
+                None | Some(Script(_)) => {}
+                Some(PublicKey(pub_bytes)) => {
+                    let target_enc = transfer
+                        .target
+                        .try_to_vec()
+                        .expect("target address encoding");
+
+                    let hash =
+                        Ripemd160::digest(sha256(&target_enc).as_slice());
+
+                    if <[u8; 20]>::from(hash) != pub_bytes {
+                        debug_log!(
+                            "the public key of the output account does not \
+                             match the transfer target"
+                        );
+                        return reject();
+                    }
+                }
+            }
         }
 
         match transparent_tx_pool.partial_cmp(&Amount::zero()) {