diff --git a/src/store/mod.rs b/src/store/mod.rs
index e799f79..6737a4e 100644
--- a/src/store/mod.rs
+++ b/src/store/mod.rs
@@ -23,6 +23,7 @@ use std::ops::RangeBounds;
 use std::sync::Arc;
 use std::sync::Mutex;
 
+use libmcaptcha::cache::messages::CachedPoWConfig;
 use libmcaptcha::AddVisitorResult;
 use libmcaptcha::MCaptcha;
 use openraft::async_trait::async_trait;
@@ -38,6 +39,7 @@ use openraft::LogId;
 use openraft::RaftLogReader;
 use openraft::RaftSnapshotBuilder;
 use openraft::RaftStorage;
+use openraft::RaftTypeConfig;
 use openraft::SnapshotMeta;
 use openraft::StorageError;
 use openraft::StorageIOError;
@@ -45,7 +47,6 @@ use openraft::StoredMembership;
 use openraft::Vote;
 use serde::Deserialize;
 use serde::Serialize;
-use sqlx::Statement;
 use tokio::sync::RwLock;
 use url::quirks::set_pathname;
 
@@ -53,6 +54,9 @@ use crate::DcacheNodeId;
 use crate::DcacheTypeConfig;
 
 use actix::prelude::*;
+use libmcaptcha::cache::messages::{
+    CachePoW, CacheResult, DeleteCaptchaResult, DeletePoW, RetrivePoW, VerifyCaptchaResult,
+};
 use libmcaptcha::master::messages::{
     AddSite as AddCaptcha, AddVisitor, GetInternalData, RemoveCaptcha, Rename as RenameCaptcha,
     SetInternalData,
@@ -61,22 +65,25 @@ use libmcaptcha::{master::embedded::master::Master as EmbeddedMaster, system::Sy
 
 pub mod system;
 
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Clone, Debug)]
 pub enum DcacheRequest {
-    //Set { key: String, value: String },
+    // master
     AddVisitor(AddVisitor),
     AddCaptcha(AddCaptcha),
     RenameCaptcha(RenameCaptcha),
     RemoveCaptcha(RemoveCaptcha),
+    //cache
+    CachePoW(CachePoW),
+    DeletePoW(DeletePoW),
+    CacheResult(CacheResult),
+    DeleteCaptchaResult(DeleteCaptchaResult),
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub enum DcacheResponse {
     AddVisitorResult(Option<AddVisitorResult>),
-    Empty,
-    //    AddCaptchaResult, All returns ()
-    //    RenameCaptchaResult,
-    //    RemoveCaptchaResult,
+    Empty, // AddCaptcha, RenameCaptcha, RemoveCaptcha, Cachepow, CacheResult,
+           // DeletePoW, DeleteCaptchaResult
 }
 
 #[derive(Debug)]
@@ -212,12 +219,11 @@ impl RaftLogReader<DcacheTypeConfig> for Arc<DcacheStore> {
 }
 
 #[async_trait]
-impl RaftSnapshotBuilder<DcacheTypeConfig, Cursor<Vec<u8>>> for Arc<DcacheStore> {
+impl RaftSnapshotBuilder<DcacheTypeConfig> for Arc<DcacheStore> {
     #[tracing::instrument(level = "trace", skip(self))]
     async fn build_snapshot(
         &mut self,
-    ) -> Result<Snapshot<DcacheNodeId, BasicNode, Cursor<Vec<u8>>>, StorageError<DcacheNodeId>>
-    {
+    ) -> Result<Snapshot<DcacheTypeConfig>, StorageError<DcacheNodeId>> {
         let data;
         let last_applied_log;
         let last_membership;
@@ -277,7 +283,6 @@ impl RaftSnapshotBuilder<DcacheTypeConfig, Cursor<Vec<u8>>> for Arc<DcacheStore>
 
 #[async_trait]
 impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
-    type SnapshotData = Cursor<Vec<u8>>;
     type LogReader = Self;
     type SnapshotBuilder = Self;
 
@@ -298,13 +303,13 @@ impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
     }
 
     #[tracing::instrument(level = "trace", skip(self, entries))]
-    async fn append_to_log(
-        &mut self,
-        entries: &[&Entry<DcacheTypeConfig>],
-    ) -> Result<(), StorageError<DcacheNodeId>> {
+    async fn append_to_log<I>(&mut self, entries: I) -> Result<(), StorageError<DcacheNodeId>>
+    where
+        I: IntoIterator<Item = Entry<DcacheTypeConfig>> + Send,
+    {
         let mut log = self.log.write().await;
         for entry in entries {
-            log.insert(entry.log_id.index, (*entry).clone());
+            log.insert(entry.log_id.index, entry);
         }
         Ok(())
     }
@@ -375,7 +380,8 @@ impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
     #[tracing::instrument(level = "trace", skip(self, entries))]
     async fn apply_to_state_machine(
         &mut self,
-        entries: &[&Entry<DcacheTypeConfig>],
+        //        entries: &[&Entry<DcacheTypeConfig>],
+        entries: &[Entry<DcacheTypeConfig>],
     ) -> Result<Vec<DcacheResponse>, StorageError<DcacheNodeId>> {
         let mut res = Vec::with_capacity(entries.len());
 
@@ -435,7 +441,42 @@ impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
                             .unwrap();
                         res.push(DcacheResponse::Empty);
                     }
+
+                    // cache
+                    DcacheRequest::CachePoW(msg) => {
+                        sm.data
+                            .cache
+                            .send(msg.clone())
+                            .await
+                            .unwrap()
+                            .await
+                            .unwrap()
+                            .unwrap();
+                        res.push(DcacheResponse::Empty);
+                    }
+                    DcacheRequest::DeletePoW(msg) => {
+                        sm.data.cache.send(msg.clone()).await.unwrap().unwrap();
+
+                        res.push(DcacheResponse::Empty);
+                    }
+
+                    DcacheRequest::CacheResult(msg) => {
+                        sm.data
+                            .cache
+                            .send(msg.clone())
+                            .await
+                            .unwrap()
+                            .await
+                            .unwrap()
+                            .unwrap();
+                        res.push(DcacheResponse::Empty);
+                    }
+                    DcacheRequest::DeleteCaptchaResult(msg) => {
+                        sm.data.cache.send(msg.clone()).await.unwrap().unwrap();
+                        res.push(DcacheResponse::Empty);
+                    }
                 },
+
                 EntryPayload::Membership(ref mem) => {
                     sm.last_membership = StoredMembership::new(Some(entry.log_id), mem.clone());
                     res.push(DcacheResponse::Empty)
@@ -448,7 +489,9 @@ impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
     #[tracing::instrument(level = "trace", skip(self))]
     async fn begin_receiving_snapshot(
         &mut self,
-    ) -> Result<Box<Self::SnapshotData>, StorageError<DcacheNodeId>> {
+        //    ) -> Result<Box<DcacheTypeConfig as RaftTypeConfig>::SnapshotData>, StorageError<DcacheNodeId>> {
+    ) -> Result<Box<<DcacheTypeConfig as RaftTypeConfig>::SnapshotData>, StorageError<DcacheNodeId>>
+    {
         Ok(Box::new(Cursor::new(Vec::new())))
     }
 
@@ -456,7 +499,7 @@ impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
     async fn install_snapshot(
         &mut self,
         meta: &SnapshotMeta<DcacheNodeId, BasicNode>,
-        snapshot: Box<Self::SnapshotData>,
+        snapshot: Box<<DcacheTypeConfig as RaftTypeConfig>::SnapshotData>,
     ) -> Result<(), StorageError<DcacheNodeId>> {
         tracing::info!(
             { snapshot_size = snapshot.get_ref().len() },
@@ -470,17 +513,12 @@ impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
 
         // Update the state machine.
         {
-            let updated_persistable_state_machine: PersistableStateMachine =
+            let updated_state_machine: PersistableStateMachine =
                 serde_json::from_slice(&new_snapshot.data).map_err(|e| {
-                    StorageIOError::new(
-                        ErrorSubject::Snapshot(new_snapshot.meta.signature()),
-                        ErrorVerb::Read,
-                        AnyError::new(&e),
-                    )
+                    StorageIOError::read_snapshot(Some(new_snapshot.meta.signature()), &e)
                 })?;
-
             let mut state_machine = self.state_machine.write().await;
-            let updated_state_machine = updated_persistable_state_machine
+            let updated_state_machine = updated_state_machine
                 .to_statemachine(state_machine.data.clone())
                 .await;
             *state_machine = updated_state_machine;
@@ -495,10 +533,7 @@ impl RaftStorage<DcacheTypeConfig> for Arc<DcacheStore> {
     #[tracing::instrument(level = "trace", skip(self))]
     async fn get_current_snapshot(
         &mut self,
-    ) -> Result<
-        Option<Snapshot<DcacheNodeId, BasicNode, Self::SnapshotData>>,
-        StorageError<DcacheNodeId>,
-    > {
+    ) -> Result<Option<Snapshot<DcacheTypeConfig>>, StorageError<DcacheNodeId>> {
         match &*self.current_snapshot.read().await {
             Some(snapshot) => {
                 let data = snapshot.data.clone();