diff --git a/application/Auth.ts b/application/Auth.ts
new file mode 100644
index 0000000..8cfaf2c
--- /dev/null
+++ b/application/Auth.ts
@@ -0,0 +1,19 @@
+export interface SignInRequest {
+  email: string;
+  password: string;
+}
+
+export interface SignInResponse {
+  succeed: boolean;
+  error?: string;
+}
+
+export interface SignUpRequest {
+  email: string;
+  password: string;
+}
+
+export interface SignUpResponse {
+  succeed: boolean;
+  error?: string;
+}
diff --git a/infrastructure/index.ts b/infrastructure/index.ts
index c5d222f..2c8d38c 100644
--- a/infrastructure/index.ts
+++ b/infrastructure/index.ts
@@ -27,4 +27,7 @@ export interface IAccountRepository {
   setLastLoginAttempt(timestamp: number): Promise<void>;
   setLastLogin(timestamp: number): Promise<void>;
   registerNewUser(user: User): Promise<void>;
+  upgradeUserToPlayer(user: User, player: Player): Promise<void>;
+  unregisterUser(id: Identifier): Promise<void>;
+  unregisterPlayer(id: Identifier): Promise<void>;
 }