diff --git a/libs/common/src/auth/opaque/default-opaque.service.ts b/libs/common/src/auth/opaque/default-opaque.service.ts
new file mode 100644
index 00000000000..2294cf038b5
--- /dev/null
+++ b/libs/common/src/auth/opaque/default-opaque.service.ts
@@ -0,0 +1,18 @@
+import { UserKey } from "../../types/key";
+
+import { OpaqueApiService } from "./opaque-api.service";
+import { OpaqueService } from "./opaque.service";
+
+export class DefaultOpaqueService implements OpaqueService {
+  constructor(private opaqueApiService: OpaqueApiService) {}
+
+  async Register(masterPassword: string, userKey: UserKey) {
+    throw new Error("Not implemented");
+    await Promise.resolve();
+  }
+
+  async Login(masterPassword: string) {
+    throw new Error("Not implemented");
+    return await Promise.resolve(null as unknown as UserKey);
+  }
+}
diff --git a/libs/common/src/auth/opaque/opaque-api.service.ts b/libs/common/src/auth/opaque/opaque-api.service.ts
new file mode 100644
index 00000000000..d9ca05ade42
--- /dev/null
+++ b/libs/common/src/auth/opaque/opaque-api.service.ts
@@ -0,0 +1,6 @@
+export abstract class OpaqueApiService {
+  abstract StartRegistration(): any;
+  abstract FinishRegistration(): any;
+  abstract StartLogin(): any;
+  abstract FinishLogin(): any;
+}
diff --git a/libs/common/src/auth/opaque/opaque.service.ts b/libs/common/src/auth/opaque/opaque.service.ts
new file mode 100644
index 00000000000..c7ee949c571
--- /dev/null
+++ b/libs/common/src/auth/opaque/opaque.service.ts
@@ -0,0 +1,14 @@
+import { UserKey } from "../../types/key";
+
+export abstract class OpaqueService {
+  /**
+   * Register a user to use the Opaque login method.
+   */
+  abstract Register(masterPassword: string, userKey: UserKey): Promise<void>;
+
+  /**
+   * Authenticate using the Opaque login method.
+   * @returns The UserKey obtained during the Opaque login flow.
+   */
+  abstract Login(masterPassword: string): Promise<UserKey>;
+}