diff --git a/src/core/dek.rs b/src/core/dek.rs
index f8b6028..aca03cd 100644
--- a/src/core/dek.rs
+++ b/src/core/dek.rs
@@ -81,7 +81,7 @@ impl Dek {
                     .unwrap();
 
                 match cursor_dek {
-                    Some(mut data) => return Ok(data.decrypt(&server_kek)),
+                    Some(data) => return Ok(data.decrypt(&server_kek)),
                     None => {
                         return Err(Error::KeyNotFound {
                             message: "DEK not found".to_string(),
@@ -103,7 +103,7 @@ impl Dek {
                     .unwrap();
 
                 match cursor_dek {
-                    Some(mut data) => return Ok(data.decrypt(&server_kek)),
+                    Some(data) => return Ok(data.decrypt(&server_kek)),
                     None => {
                         return Err(Error::KeyNotFound {
                             message: "DEK not found".to_string(),
diff --git a/src/core/session.rs b/src/core/session.rs
index e51be34..ef63772 100644
--- a/src/core/session.rs
+++ b/src/core/session.rs
@@ -31,7 +31,7 @@ impl Session {
         let db = mongo_client.database("test");
         let collection_session: Collection<Session> = db.collection("sessions");
 
-        let mut session = self.clone();
+        let session = self.clone();
         let encrypted_session = session.encrypt(key);
 
         match collection_session.insert_one(encrypted_session, None).await {
diff --git a/src/core/user.rs b/src/core/user.rs
index bc96e75..825dadd 100644
--- a/src/core/user.rs
+++ b/src/core/user.rs
@@ -98,7 +98,7 @@ impl User {
                     )
                     .await
                 {
-                    Ok(Some(mut user)) => {
+                    Ok(Some(user)) => {
                         let decrypted_user = user.decrypt(&dek_data.dek);
                         return Ok(decrypted_user);
                     }
@@ -132,7 +132,7 @@ impl User {
             )
             .await
         {
-            Ok(Some(mut user)) => {
+            Ok(Some(user)) => {
                 let decrypted_user = user.decrypt(&dek_data.dek);
                 return Ok(decrypted_user);
             }
@@ -150,7 +150,7 @@ impl User {
         let collection: Collection<User> = db.collection("users");
         let collection_dek: Collection<Dek> = db.collection("deks");
 
-        // let mut cursor = collection.find(None, None).await.unwrap();
+        // let cursor = collection.find(None, None).await.unwrap();
         let mut cursor_dek = collection_dek.find(None, None).await.unwrap();
 
         let mut users = Vec::new();
@@ -159,7 +159,7 @@ impl User {
         // iterate over the users and decrypt the data
         while let Some(dek) = cursor_dek.next().await {
             let dek_data: Dek = match dek {
-                Ok(mut data) => data.decrypt(&kek),
+                Ok(data) => data.decrypt(&kek),
                 Err(_) => {
                     return Err(Error::ServerError {
                         message: "Failed to get DEK".to_string(),
@@ -181,7 +181,7 @@ impl User {
                 .unwrap();
 
             match cursor_user {
-                Some(mut user) => {
+                Some(user) => {
                     let user_data = user.decrypt(&dek_data.dek);
 
                     users.push(UserResponse {
@@ -317,7 +317,7 @@ impl User {
             }
         };
         // get user
-        let mut user = match collection
+        let user = match collection
             .find_one(
                 doc! { "email": Encryption::encrypt_data(&email, &dek_data.dek) },
                 None,
diff --git a/src/traits/decryption.rs b/src/traits/decryption.rs
index 8525657..a460bba 100644
--- a/src/traits/decryption.rs
+++ b/src/traits/decryption.rs
@@ -4,14 +4,14 @@ use serde_json::Value;
 use crate::utils::encryption_utils::Encryption;
 
 pub trait Decrypt {
-    fn decrypt(&mut self, key: &str) -> Self;
+    fn decrypt(&self, key: &str) -> Self;
 }
 
 impl<T> Decrypt for T
 where
     T: Serialize + DeserializeOwned,
 {
-    fn decrypt(&mut self, key: &str) -> Self {
+    fn decrypt(&self, key: &str) -> Self {
         // Serialize the object to JSON
         let json_str = serde_json::to_string(self).unwrap();
 
diff --git a/src/traits/encryption.rs b/src/traits/encryption.rs
index f1f921c..1a5abff 100644
--- a/src/traits/encryption.rs
+++ b/src/traits/encryption.rs
@@ -4,14 +4,14 @@ use serde_json::Value;
 use crate::utils::encryption_utils::Encryption;
 
 pub trait Encrypt {
-    fn encrypt(&mut self, key: &str) -> Self;
+    fn encrypt(&self, key: &str) -> Self;
 }
 
 impl<T> Encrypt for T
 where
     T: Serialize + DeserializeOwned,
 {
-    fn encrypt(&mut self, key: &str) -> Self {
+    fn encrypt(&self, key: &str) -> Self {
         // Serialize the object to JSON
         let json_str = serde_json::to_string(self).unwrap();