feat: the CLOAK privacy solution (#1737)

Co-authored-by: Ho <fan@scroll.io>
Co-authored-by: Rohit Narurkar <rohit.narurkar@proton.me>
Co-authored-by: Péter Garamvölgyi <peter@scroll.io>

crates/l2geth/src/rpc_client.rs

@@ -5,7 +5,7 @@ use alloy::{
 };
 use eyre::Result;
 use libzkp::tasks::ChunkInterpreter;
-use sbv_primitives::types::Network;
+use sbv_primitives::types::{consensus::TxL1Message, Network};
 use serde::{Deserialize, Serialize};
 
 fn default_max_retry() -> u32 {
@@ -168,6 +168,40 @@ impl<T: Provider<Network>> ChunkInterpreter for RpcClient<'_, T> {
         self.handle
             .block_on(fetch_storage_node_async(&self.provider, node_hash))
     }
+
+    fn try_fetch_l1_msgs(&self, block_number: u64) -> Result<Vec<TxL1Message>> {
+        async fn fetch_l1_msgs(
+            provider: impl Provider<Network>,
+            block_number: u64,
+        ) -> Result<Vec<TxL1Message>> {
+            let block_number_hex = format!("0x{:x}", block_number);
+
+            #[derive(Deserialize, Debug)]
+            #[serde(untagged)]
+            enum NullOrVec {
+                Null,                  // matches JSON `null`
+                Vec(Vec<TxL1Message>), // matches JSON array
+            }
+
+            Ok(
+                match provider
+                    .client()
+                    .request::<_, NullOrVec>(
+                        "scroll_getL1MessagesInBlock",
+                        (block_number_hex, "synced"),
+                    )
+                    .await?
+                {
+                    NullOrVec::Null => Vec::new(),
+                    NullOrVec::Vec(r) => r,
+                },
+            )
+        }
+
+        tracing::debug!("fetch L1 msgs for {block_number}");
+        self.handle
+            .block_on(fetch_l1_msgs(&self.provider, block_number))
+    }
 }
 
 #[cfg(test)]
@@ -218,4 +252,16 @@ mod tests {
 
         println!("{}", serde_json::to_string_pretty(&wit2).unwrap());
     }
+
+    #[test]
+    #[ignore = "Requires L2GETH_ENDPOINT environment variable"]
+    fn test_try_fetch_l1_messages() {
+        let config = create_config_from_env();
+        let client_core = RpcClientCore::create(&config).expect("Failed to create RPC client");
+        let client = client_core.get_client();
+
+        let msgs = client.try_fetch_l1_msgs(32).expect("should success");
+
+        println!("{}", serde_json::to_string_pretty(&msgs).unwrap());
+    }
 }