diff --git a/matrix_sdk_crypto/src/user_identity.rs b/matrix_sdk_crypto/src/user_identity.rs
index 9fd87033..3681fe33 100644
--- a/matrix_sdk_crypto/src/user_identity.rs
+++ b/matrix_sdk_crypto/src/user_identity.rs
@@ -120,6 +120,8 @@ impl UserSigningPubkey {
             .next()
             .ok_or(SignatureError::MissingSigningKey)?;
 
+        // TODO check that the usage is OK.
+
         verify_json(
             &self.0.user_id,
             &DeviceKeyId::try_from(key_id.as_str())?,
@@ -138,6 +140,8 @@ impl SelfSigningPubkey {
             .next()
             .ok_or(SignatureError::MissingSigningKey)?;
 
+        // TODO check that the usage is OK.
+
         verify_json(
             &self.0.user_id,
             &DeviceKeyId::try_from(key_id.as_str())?,
@@ -160,6 +164,10 @@ impl UserIdentity {
             self_signing_key,
         })
     }
+
+    pub fn is_device_signed(&self, device: &Device) -> Result<(), SignatureError> {
+        self.self_signing_key.verify_device(device)
+    }
 }
 
 pub struct OwnUserIdentity {
@@ -187,6 +195,11 @@ impl OwnUserIdentity {
             verified: Arc::new(AtomicBool::new(false)),
         })
     }
+
+    pub fn is_identity_signed(&self, identity: &UserIdentity) -> Result<(), SignatureError> {
+        self.user_signing_key
+            .verify_master_key(&identity.master_key)
+    }
 }
 
 #[cfg(test)]