diff --git a/resources/migrations/sql/create_tables_001.sql b/resources/migrations/sql/create_tables_001.sql
index 78a6d40..6fb4169 100644
--- a/resources/migrations/sql/create_tables_001.sql
+++ b/resources/migrations/sql/create_tables_001.sql
@@ -2,12 +2,14 @@ PRAGMA journal_mode= WAL;
 
 CREATE TABLE IF NOT EXISTS ledger_internal
 (
+    -- th
     id            INTEGER PRIMARY KEY AUTOINCREMENT,
     creation_time DATETIME DEFAULT CURRENT_TIMESTAMP,
     cookie_secret TEXT NOT NULL
-
 );
 
+INSERT INTO ledger_internal(cookie_secret) VALUES ('aaaabbbbccccddddeeeeffffgggghhhhiiiijjjjkkkk');
+
 CREATE TABLE IF NOT EXISTS users
 (
     id            INTEGER PRIMARY KEY AUTOINCREMENT,
diff --git a/src/db/_ledger_internal.rs b/src/db/_ledger_internal.rs
index 337a2f1..771dbc8 100644
--- a/src/db/_ledger_internal.rs
+++ b/src/db/_ledger_internal.rs
@@ -5,6 +5,10 @@ use base64::{Engine as _, engine::general_purpose};
 struct LedgerInternal {}
 
 impl LedgerInternal {
+    pub fn new() -> LedgerInternal {
+        LedgerInternal {}
+    }
+
     fn _decode_cookie_secret(row: &Row) -> Result<Vec<u8>> {
         let encoded: String = row.get(0)?;
         let ret = general_purpose::STANDARD.decode(encoded).unwrap();
@@ -14,26 +18,63 @@ impl LedgerInternal {
     pub fn get_cookie_secret(&self, tx: &Transaction) -> CustomResult<Vec<u8>> {
         let q = "SELECT cookie_secret
                       FROM ledger_internal
-                      ORDER BY cookie_secret DESC
+                      ORDER BY id DESC
                       LIMIT 1";
         tx.query_row(q, params![], Self::_decode_cookie_secret)
             .map_err(Error::SqlError)
     }
 
-    pub fn set_cookie_secret(&self, tx: &Transaction, secret: &Vec<u8>) {
+    pub fn set_cookie_secret(&self, tx: &mut Transaction, secret: &Vec<u8>) -> CustomResult<()> {
+        let encoded = general_purpose::STANDARD.encode(&secret);
         let q = "CREATE TEMPORARY TABLE foo
                          AS SELECT * FROM ledger_internal
-                            ORDER BY cookie_secret DESC
+                            ORDER BY id DESC
                             LIMIT 1";
+        tx.execute(q, params![]).map_err(Error::SqlError)?;
+
+        let q = "UPDATE foo SET id = NULL, cookie_secret = ?1";
+        tx.execute(q, params![encoded]).map_err(Error::SqlError)?;
+
+        let q = "INSERT INTO ledger_internal SELECT * FROM foo";
+        tx.execute(q, params![]).map_err(Error::SqlError)?;
+
+        let q = "DROP TABLE foo";
+        tx.execute(q, params![]).map_err(Error::SqlError)?;
+
+        Ok(())
     }
 }
 
 #[cfg(test)]
 mod test_ledger_internal {
+    use crate::migration;
     use super::*;
 
     #[test]
-    fn test_foo() {
+    fn test_initial_cookie_secret() -> CustomResult<()>{
+        let mut conn = Connection::open_in_memory().unwrap();
+        migration::apply_migrations(&mut conn).unwrap();
+        let tx = conn.transaction().unwrap();
+        let service = LedgerInternal::new();
+        let foo = service.get_cookie_secret(&tx)?;
+        assert!(foo.len() >= 32);
 
+        Ok(())
+    }
+
+    #[test]
+    fn test_cookie_secret() -> CustomResult<()> {
+        let mut conn = Connection::open_in_memory().unwrap();
+        migration::apply_migrations(&mut conn).unwrap();
+        let mut tx = conn.transaction().unwrap();
+        let service = LedgerInternal::new();
+        service.set_cookie_secret(&mut tx, &vec![3u8])?;
+        let foo = service.get_cookie_secret(&tx)?;
+        assert_eq!(foo, vec![3u8]);
+
+        service.set_cookie_secret(&mut tx, &vec![7u8, 1u8, 4u8])?;
+        let foo = service.get_cookie_secret(&tx)?;
+        assert_eq!(foo, vec![7u8, 1u8, 4u8]);
+        Ok(())
     }
 }