diff --git a/src/interfaces/grpc.rs b/src/interfaces/grpc.rs
index d42cc36..8cd01ae 100644
--- a/src/interfaces/grpc.rs
+++ b/src/interfaces/grpc.rs
@@ -32,6 +32,22 @@ impl MeeSignService {
     pub fn new(state: Arc<Mutex<State>>) -> Self {
         MeeSignService { state }
     }
+
+    async fn check_client_auth(
+        &self,
+        certs: &Option<Arc<Vec<Certificate>>>,
+        required: bool,
+    ) -> Result<(), Status> {
+        if let Some(certs) = certs {
+            let device_id = certs.get(0).map(cert_to_id).unwrap_or(vec![]);
+            if !self.state.lock().await.device_activated(&device_id) {
+                return Err(Status::unauthenticated("Unknown device certificate"));
+            }
+        } else if required {
+            return Err(Status::unauthenticated("Authentication required"));
+        }
+        Ok(())
+    }
 }
 
 #[tonic::async_trait]
@@ -43,13 +59,9 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::ServerInfoRequest>,
     ) -> Result<Response<msg::ServerInfo>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         debug!("ServerInfoRequest");
-        if let Some(certs) = request.peer_certs() {
-            let device_id = certs.get(0).map(cert_to_id).unwrap_or(vec![]);
-            if !self.state.lock().await.device_activated(&device_id) {
-                return Err(Status::unauthenticated("Unknown device certificate"));
-            }
-        }
         Ok(Response::new(msg::ServerInfo {
             version: crate::VERSION.unwrap_or("unknown").to_string(),
         }))
@@ -59,6 +71,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::RegistrationRequest>,
     ) -> Result<Response<msg::RegistrationResponse>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let request = request.into_inner();
         let name = request.name;
         let kind = DeviceKind::try_from(request.kind).unwrap();
@@ -90,6 +104,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::SignRequest>,
     ) -> Result<Response<msg::Task>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let request = request.into_inner();
         let group_id = request.group_id;
         let name = request.name;
@@ -109,6 +125,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::DecryptRequest>,
     ) -> Result<Response<msg::Task>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let request = request.into_inner();
         let group_id = request.group_id;
         let name = request.name;
@@ -129,6 +147,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::TaskRequest>,
     ) -> Result<Response<msg::Task>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let request = request.into_inner();
         let task_id = Uuid::from_slice(&request.task_id).unwrap();
         let device_id = request.device_id;
@@ -144,9 +164,6 @@ impl MeeSign for MeeSignService {
         );
 
         let state = self.state.lock().await;
-        if device_id.is_some() {
-            state.device_activated(device_id.as_ref().unwrap());
-        }
         let task = state.get_task(&task_id).unwrap();
         let request = Some(task.get_request());
 
@@ -158,9 +175,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::TaskUpdate>,
     ) -> Result<Response<msg::Resp>, Status> {
-        if request.peer_certs().is_none() {
-            return Err(Status::unauthenticated("Authentication required"));
-        }
+        self.check_client_auth(&request.peer_certs(), true).await?;
+
         let device_id = request
             .peer_certs()
             .and_then(|certs| certs.get(0).map(cert_to_id))
@@ -187,7 +203,6 @@ impl MeeSign for MeeSignService {
         );
 
         let mut state = self.state.lock().await;
-        state.device_activated(&device_id);
         let result = state.update_task(&task_id, &device_id, &data, attempt);
 
         match result {
@@ -202,6 +217,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::TasksRequest>,
     ) -> Result<Response<msg::Tasks>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let request = request.into_inner();
         let device_id = request.device_id;
         let device_str = device_id
@@ -212,7 +229,6 @@ impl MeeSign for MeeSignService {
 
         let state = self.state.lock().await;
         let tasks = if let Some(device_id) = device_id {
-            state.device_activated(&device_id);
             state
                 .get_device_tasks(&device_id)
                 .iter()
@@ -233,6 +249,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::GroupsRequest>,
     ) -> Result<Response<msg::Groups>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let request = request.into_inner();
         let device_id = request.device_id;
         let device_str = device_id
@@ -243,7 +261,6 @@ impl MeeSign for MeeSignService {
 
         let state = self.state.lock().await;
         let groups = if let Some(device_id) = device_id {
-            state.device_activated(&device_id);
             state
                 .get_device_groups(&device_id)
                 .iter()
@@ -264,6 +281,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::GroupRequest>,
     ) -> Result<Response<msg::Task>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let request = request.into_inner();
         let name = request.name;
         let device_ids = request.device_ids;
@@ -295,8 +314,10 @@ impl MeeSign for MeeSignService {
 
     async fn get_devices(
         &self,
-        _request: Request<msg::DevicesRequest>,
+        request: Request<msg::DevicesRequest>,
     ) -> Result<Response<msg::Devices>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         debug!("DevicesRequest");
 
         let resp = msg::Devices {
@@ -313,6 +334,8 @@ impl MeeSign for MeeSignService {
     }
 
     async fn log(&self, request: Request<msg::LogRequest>) -> Result<Response<msg::Resp>, Status> {
+        self.check_client_auth(&request.peer_certs(), false).await?;
+
         let device_id = request
             .peer_certs()
             .and_then(|certs| certs.get(0).map(cert_to_id));
@@ -324,13 +347,6 @@ impl MeeSign for MeeSignService {
         let message = request.into_inner().message.replace('\n', "\\n");
         debug!("LogRequest device_id={} message={}", device_str, message);
 
-        if device_id.is_some() {
-            self.state
-                .lock()
-                .await
-                .device_activated(device_id.as_ref().unwrap());
-        }
-
         Ok(Response::new(msg::Resp {
             message: "OK".into(),
         }))
@@ -340,9 +356,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::TaskDecision>,
     ) -> Result<Response<msg::Resp>, Status> {
-        if request.peer_certs().is_none() {
-            return Err(Status::unauthenticated("Authentication required"));
-        }
+        self.check_client_auth(&request.peer_certs(), true).await?;
+
         let device_id = request
             .peer_certs()
             .and_then(|certs| certs.get(0).map(cert_to_id))
@@ -362,7 +377,6 @@ impl MeeSign for MeeSignService {
         let state = self.state.clone();
         tokio::task::spawn(async move {
             let mut state = state.lock().await;
-            state.device_activated(&device_id);
             state.decide_task(&task_id, &device_id, accept);
         });
 
@@ -375,9 +389,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::TaskAcknowledgement>,
     ) -> Result<Response<msg::Resp>, Status> {
-        if request.peer_certs().is_none() {
-            return Err(Status::unauthenticated("Authentication required"));
-        }
+        self.check_client_auth(&request.peer_certs(), true).await?;
+
         let device_id = request
             .peer_certs()
             .and_then(|certs| certs.get(0).map(cert_to_id))
@@ -392,7 +405,6 @@ impl MeeSign for MeeSignService {
         );
 
         let mut state = self.state.lock().await;
-        state.device_activated(&device_id);
         state.acknowledge_task(&Uuid::from_slice(&task_id).unwrap(), &device_id);
 
         Ok(Response::new(msg::Resp {
@@ -404,9 +416,8 @@ impl MeeSign for MeeSignService {
         &self,
         request: Request<msg::SubscribeRequest>,
     ) -> Result<Response<Self::SubscribeUpdatesStream>, Status> {
-        if request.peer_certs().is_none() {
-            return Err(Status::unauthenticated("Authentication required"));
-        }
+        self.check_client_auth(&request.peer_certs(), true).await?;
+
         let device_id = request
             .peer_certs()
             .and_then(|certs| certs.get(0).map(cert_to_id))
diff --git a/src/state.rs b/src/state.rs
index c672964..bb14682 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 
-use log::{debug, error, warn};
+use log::{debug, warn};
 use uuid::Uuid;
 
 use crate::device::Device;
@@ -293,7 +293,7 @@ impl State {
             device.activated();
             true
         } else {
-            error!("Unknown Device ID {}", utils::hextrunc(device_id));
+            debug!("Unknown Device ID {}", utils::hextrunc(device_id));
             false
         }
     }