diff --git a/src/api/ecdar_api.rs b/src/api/ecdar_api.rs
index 81916ca..f78a59f 100644
--- a/src/api/ecdar_api.rs
+++ b/src/api/ecdar_api.rs
@@ -1,7 +1,7 @@
+use crate::api::hashing_context::HashingContextTrait;
 use crate::api::server::server::get_auth_token_request::user_credentials;
 use crate::entities::access;
 use crate::entities::session;
-use bcrypt::hash;
 use regex::Regex;
 use sea_orm::SqlErr;
 use std::sync::Arc;
@@ -38,10 +38,9 @@ pub struct ConcreteEcdarApi {
     session_context: Arc<dyn SessionContextTrait>,
     user_context: Arc<dyn UserContextTrait>,
     reveaal_context: Arc<dyn EcdarBackend>,
+    hashing_context: Arc<dyn HashingContextTrait>,
 }
 
-const HASH_COST: u32 = 12;
-
 /// Updates or creates a session in the database for a given user.
 ///
 ///
@@ -131,6 +130,7 @@ impl ConcreteEcdarApi {
         session_context: Arc<dyn SessionContextTrait>,
         user_context: Arc<dyn UserContextTrait>,
         reveaal_context: Arc<dyn EcdarBackend>,
+        hashing_context: Arc<dyn HashingContextTrait>,
     ) -> Self {
         ConcreteEcdarApi {
             access_context,
@@ -140,6 +140,7 @@ impl ConcreteEcdarApi {
             session_context,
             user_context,
             reveaal_context,
+            hashing_context,
         }
     }
 }
@@ -256,7 +257,7 @@ impl EcdarApi for ConcreteEcdarApi {
 
         // Record to be inserted in database
         let new_user = user::Model {
-            id: Default::default(),
+            id: uid,
             username: match message.clone().username {
                 Some(username) => {
                     if is_valid_username(username.as_str()) {
@@ -278,7 +279,7 @@ impl EcdarApi for ConcreteEcdarApi {
                 None => user.email,
             },
             password: match message.clone().password {
-                Some(password) => hash(password, HASH_COST).unwrap(),
+                Some(password) => self.hashing_context.hash_password(password),
                 None => user.password,
             },
         };
@@ -384,7 +385,7 @@ impl EcdarApi for ConcreteEcdarApi {
 async fn get_auth_find_user_helper(
     user_context: Arc<dyn UserContextTrait>,
     user_credentials: UserCredentials,
-) -> Result<UserEntity, Status> {
+) -> Result<user::Model, Status> {
     if let Some(user) = user_credentials.user {
         match user {
             user_credentials::User::Username(username) => Ok(user_context
@@ -485,7 +486,7 @@ impl EcdarApiAuth for ConcreteEcdarApi {
             return Err(Status::new(Code::InvalidArgument, "Invalid email"));
         }
 
-        let user = UserEntity {
+        let user = user::Model {
             id: Default::default(),
             username: message.clone().username,
             password: message.clone().password,
diff --git a/src/api/hashing_context.rs b/src/api/hashing_context.rs
new file mode 100644
index 0000000..a4cd7b5
--- /dev/null
+++ b/src/api/hashing_context.rs
@@ -0,0 +1,18 @@
+use bcrypt::{hash, verify, DEFAULT_COST};
+
+pub trait HashingContextTrait: Send + Sync {
+    fn hash_password(&self, password: String) -> String;
+    fn verify_password(&self, password: String, hash: &str) -> bool;
+}
+
+pub struct HashingContext;
+
+impl HashingContextTrait for HashingContext {
+    fn hash_password(&self, password: String) -> String {
+        hash(password, DEFAULT_COST).unwrap()
+    }
+
+    fn verify_password(&self, password: String, hash: &str) -> bool {
+        verify(password, hash).unwrap()
+    }
+}
diff --git a/src/api/mod.rs b/src/api/mod.rs
index eae1c43..40d3555 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -1,4 +1,5 @@
 pub mod auth;
 pub mod ecdar_api;
+pub mod hashing_context;
 pub mod reveaal_context;
 pub mod server;
diff --git a/src/api/server.rs b/src/api/server.rs
index 4923a2a..17eb7f0 100644
--- a/src/api/server.rs
+++ b/src/api/server.rs
@@ -5,6 +5,7 @@ use tonic::transport::Server;
 
 use crate::api::auth;
 use crate::api::ecdar_api::ConcreteEcdarApi;
+use crate::api::hashing_context::HashingContextTrait;
 use crate::api::server::server::ecdar_api_auth_server::EcdarApiAuthServer;
 use crate::api::server::server::ecdar_api_server::EcdarApiServer;
 use crate::api::server::server::ecdar_backend_server::{EcdarBackend, EcdarBackendServer};
@@ -27,6 +28,7 @@ pub async fn start_grpc_server(
     session_context: Arc<dyn SessionContextTrait>,
     user_context: Arc<dyn UserContextTrait>,
     reveaal_context: Arc<dyn EcdarBackend>,
+    hashing_context: Arc<dyn HashingContextTrait>,
 ) -> Result<(), Box<dyn std::error::Error>> {
     // defining address for our service
     let addr = env::var("API_ADDRESS")
@@ -44,6 +46,7 @@ pub async fn start_grpc_server(
         session_context,
         user_context,
         reveaal_context,
+        hashing_context,
     );
 
     // adding services to our server.
diff --git a/src/main.rs b/src/main.rs
index 189f531..e2a9694 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ mod database;
 mod entities;
 mod tests;
 
+use crate::api::hashing_context::HashingContext;
 use crate::api::reveaal_context::ReveaalContext;
 use crate::database::access_context::AccessContext;
 use crate::database::database_context::{PostgresDatabaseContext, SQLiteDatabaseContext};
@@ -39,6 +40,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     let session_context = Arc::new(SessionContext::new(db_context.clone()));
     let in_use_context = Arc::new(InUseContext::new(db_context.clone()));
     let reveaal_context = Arc::new(ReveaalContext);
+    let hashing_context = Arc::new(HashingContext);
 
     start_grpc_server(
         access_context,
@@ -48,6 +50,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
         session_context,
         user_context,
         reveaal_context,
+        hashing_context,
     )
     .await
     .unwrap();
diff --git a/src/tests/api/helpers.rs b/src/tests/api/helpers.rs
index fa90745..e652e5e 100644
--- a/src/tests/api/helpers.rs
+++ b/src/tests/api/helpers.rs
@@ -1,6 +1,7 @@
 #![cfg(test)]
 
 use crate::api::ecdar_api::ConcreteEcdarApi;
+use crate::api::hashing_context::HashingContextTrait;
 use crate::api::server::server::ecdar_backend_server::EcdarBackend;
 use crate::api::server::server::{
     QueryRequest, QueryResponse, SimulationStartRequest, SimulationStepRequest,
@@ -29,6 +30,7 @@ pub fn get_mock_concrete_ecdar_api(mock_services: MockServices) -> ConcreteEcdar
         Arc::new(mock_services.session_context_mock),
         Arc::new(mock_services.user_context_mock),
         Arc::new(mock_services.reveaal_context_mock),
+        Arc::new(mock_services.hashing_context_mock),
     )
 }
 
@@ -41,6 +43,7 @@ pub fn get_mock_services() -> MockServices {
         session_context_mock: MockSessionContext::new(),
         user_context_mock: MockUserContext::new(),
         reveaal_context_mock: MockReveaalContext::new(),
+        hashing_context_mock: MockHashingContext::new(),
     }
 }
 
@@ -52,6 +55,7 @@ pub struct MockServices {
     pub(crate) session_context_mock: MockSessionContext,
     pub(crate) user_context_mock: MockUserContext,
     pub(crate) reveaal_context_mock: MockReveaalContext,
+    pub(crate) hashing_context_mock: MockHashingContext,
 }
 
 mock! {
@@ -153,3 +157,11 @@ mock! {
         async fn take_simulation_step(&self, request: Request<SimulationStepRequest>) -> Result<Response<SimulationStepResponse>, Status>;
     }
 }
+
+mock! {
+    pub HashingContext {}
+    impl HashingContextTrait for HashingContext {
+        fn hash_password(&self, password: String) -> String;
+        fn verify_password(&self, password: String, hash: &str) -> bool;
+    }
+}
diff --git a/src/tests/api/user_logic.rs b/src/tests/api/user_logic.rs
index 82ea804..0052ea7 100644
--- a/src/tests/api/user_logic.rs
+++ b/src/tests/api/user_logic.rs
@@ -214,21 +214,20 @@ async fn test_create_user_valid_request_returns_ok() {
 
 #[tokio::test]
 async fn update_user_returns_ok() {
-    //todo!(update user implementation should be changed to populate unchanged fields with existing values)
     let mut mock_services = get_mock_services();
 
     let old_user = user::Model {
         id: 1,
-        email: "newuser@example.com".to_string(),
+        email: "olduser@example.com".to_string(),
         username: "old_username".to_string(),
         password: "StrongPassword123".to_string(),
     };
 
-    let user = user::Model {
+    let new_user = user::Model {
         id: 1,
         email: "newuser@example.com".to_string(),
         username: "new_username".to_string(),
-        password: "StrongPassword123".to_string(),
+        password: "g76df2gd7hd837g8hjd8723hd8gd823d82d3".to_string(),
     };
 
     mock_services
@@ -237,11 +236,17 @@ async fn update_user_returns_ok() {
         .with(predicate::eq(1))
         .returning(move |_| Ok(Some(old_user.clone())));
 
+    mock_services
+        .hashing_context_mock
+        .expect_hash_password()
+        .with(predicate::eq("StrongPassword123".to_string()))
+        .returning(move |_| "g76df2gd7hd837g8hjd8723hd8gd823d82d3".to_string());
+
     mock_services
         .user_context_mock
         .expect_update()
-        .with(predicate::eq(user.clone()))
-        .returning(move |_| Ok(user.clone()));
+        .with(predicate::eq(new_user.clone()))
+        .returning(move |_| Ok(new_user.clone()));
 
     let api = get_mock_concrete_ecdar_api(mock_services);
 
@@ -264,17 +269,10 @@ async fn update_user_returns_ok() {
 async fn update_user_non_existant_user_returns_err() {
     let mut mock_services = get_mock_services();
 
-    let user = user::Model {
-        id: 1,
-        email: "new_test@test".to_string(),
-        username: "new_test_user".to_string(),
-        password: "new_test_pass".to_string(),
-    };
-
     mock_services
         .user_context_mock
-        .expect_update()
-        .with(predicate::eq(user.clone()))
+        .expect_get_by_id()
+        .with(predicate::eq(1))
         .returning(move |_| Err(DbErr::RecordNotFound("".to_string())));
 
     let api = get_mock_concrete_ecdar_api(mock_services);
@@ -289,7 +287,7 @@ async fn update_user_non_existant_user_returns_err() {
         .metadata_mut()
         .insert("uid", metadata::MetadataValue::from_str("1").unwrap());
 
-    let update_user_response = api.update_user(update_user_request).await;
+    let res = api.update_user(update_user_request).await;
 
-    assert!(update_user_response.is_err())
+    assert_eq!(res.unwrap_err().code(), Code::Internal);
 }