diff --git a/crates/common/src/hashchain.rs b/crates/common/src/hashchain.rs
index a6593137..5ab7571f 100644
--- a/crates/common/src/hashchain.rs
+++ b/crates/common/src/hashchain.rs
@@ -8,10 +8,7 @@ use std::{
 
 use crate::{
     keys::VerifyingKey,
-    operation::{
-        AddDataArgs, CreateAccountArgs, KeyOperationArgs, Operation, RegisterServiceArgs,
-        ServiceChallenge, ServiceChallengeInput,
-    },
+    operation::{AddDataArgs, KeyOperationArgs, Operation},
     tree::{Digest, Hasher},
 };
 
@@ -69,16 +66,6 @@ impl Hashchain {
         Ok(hc)
     }
 
-    pub fn register_service(id: String, challenge: ServiceChallenge) -> Result<Hashchain> {
-        let mut hc = Hashchain::empty(id.clone());
-        let operation = Operation::RegisterService(RegisterServiceArgs {
-            id,
-            creation_gate: challenge,
-        });
-        hc.perform_operation(operation)?;
-        Ok(hc)
-    }
-
     pub fn empty(id: String) -> Self {
         Self {
             id,
diff --git a/crates/common/src/test_utils.rs b/crates/common/src/test_utils.rs
index 626fe722..703a397b 100644
--- a/crates/common/src/test_utils.rs
+++ b/crates/common/src/test_utils.rs
@@ -50,10 +50,10 @@ impl TestTreeState {
     pub fn register_service(&mut self, service_id: String) -> Service {
         let service_key = create_mock_signing_key();
 
-        let hashchain = Hashchain::register_service(
+        let hashchain = Hashchain::from_operation(Operation::new_register_service(
             service_id.clone(),
             ServiceChallenge::from(service_key.clone()),
-        )
+        ))
         .unwrap();
 
         let key_hash = hashchain.get_keyhash();
diff --git a/crates/common/src/tree.rs b/crates/common/src/tree.rs
index fda2c349..730525b7 100644
--- a/crates/common/src/tree.rs
+++ b/crates/common/src/tree.rs
@@ -468,9 +468,7 @@ where
                     self.insert(account_key_hash, new_account_chain)?,
                 ))
             }
-            Operation::RegisterService(RegisterServiceArgs {
-                id, creation_gate, ..
-            }) => {
+            Operation::RegisterService(RegisterServiceArgs { id, .. }) => {
                 let hashed_id = Digest::hash(id);
                 let key_hash = KeyHash::with::<Hasher>(hashed_id);
 
@@ -483,7 +481,7 @@ where
                 };
 
                 debug!("creating new hashchain for service id {}", id);
-                let chain = Hashchain::register_service(id.clone(), creation_gate.clone())?;
+                let chain = Hashchain::from_operation(operation.clone())?;
 
                 Ok(Proof::Insert(
                     self.insert(KeyHash::with::<Hasher>(hashed_id), chain)?,