diff --git a/src/lib/server/db/client.ts b/src/lib/server/db/client.ts
index a4e2cdb..c3c64ad 100644
--- a/src/lib/server/db/client.ts
+++ b/src/lib/server/db/client.ts
@@ -2,6 +2,14 @@ import { and, eq } from "drizzle-orm";
 import db from "./drizzle";
 import { client, userClient } from "./schema";
 
+export const createClient = async (pubKey: string, userId: number) => {
+  await db.transaction(async (tx) => {
+    const insertRes = await tx.insert(client).values({ pubKey }).returning({ id: client.id });
+    const { id: clientId } = insertRes[0]!;
+    await tx.insert(userClient).values({ userId, clientId });
+  });
+};
+
 export const getClientByPubKey = async (pubKey: string) => {
   const clients = await db.select().from(client).where(eq(client.pubKey, pubKey)).execute();
   return clients[0] ?? null;
diff --git a/src/lib/server/modules/auth.ts b/src/lib/server/modules/auth.ts
index 9ab7420..4d456b1 100644
--- a/src/lib/server/modules/auth.ts
+++ b/src/lib/server/modules/auth.ts
@@ -1,3 +1,4 @@
+import { error } from "@sveltejs/kit";
 import jwt from "jsonwebtoken";
 import env from "$lib/server/loadenv";
 
@@ -36,3 +37,22 @@ export const verifyToken = (token: string) => {
     return TokenError.INVALID;
   }
 };
+
+export const authenticate = (request: Request) => {
+  const accessToken = request.headers.get("Authorization");
+  if (!accessToken?.startsWith("Bearer ")) {
+    error(401, "Token required");
+  }
+
+  const tokenData = verifyToken(accessToken.slice(7));
+  if (tokenData === TokenError.EXPIRED) {
+    error(401, "Token expired");
+  } else if (tokenData === TokenError.INVALID || tokenData.type !== "access") {
+    error(401, "Invalid token");
+  }
+
+  return {
+    userId: tokenData.userId,
+    clientId: tokenData.clientId,
+  };
+};
diff --git a/src/lib/server/services/key.ts b/src/lib/server/services/key.ts
new file mode 100644
index 0000000..4d57e08
--- /dev/null
+++ b/src/lib/server/services/key.ts
@@ -0,0 +1,10 @@
+import { error } from "@sveltejs/kit";
+import { createClient, getClientByPubKey } from "$lib/server/db/client";
+
+export const registerPubKey = async (userId: number, pubKey: string) => {
+  if (await getClientByPubKey(pubKey)) {
+    error(409, "Public key already registered");
+  }
+
+  await createClient(pubKey, userId);
+};
diff --git a/src/routes/(fullscreen)/auth/login/service.ts b/src/routes/(fullscreen)/auth/login/service.ts
index f88dbc8..47f8f5b 100644
--- a/src/routes/(fullscreen)/auth/login/service.ts
+++ b/src/routes/(fullscreen)/auth/login/service.ts
@@ -1,8 +1,7 @@
-import { callAPI } from "$lib/hooks";
 import { accessTokenStore } from "$lib/stores";
 
 export const requestLogin = async (email: string, password: string) => {
-  const res = await callAPI("/api/auth/login", {
+  const res = await fetch("/api/auth/login", {
     method: "POST",
     headers: {
       "Content-Type": "application/json",
diff --git a/src/routes/(fullscreen)/key/export/+page.svelte b/src/routes/(fullscreen)/key/export/+page.svelte
index 14d2656..73fa06a 100644
--- a/src/routes/(fullscreen)/key/export/+page.svelte
+++ b/src/routes/(fullscreen)/key/export/+page.svelte
@@ -2,6 +2,7 @@
   import { Button, TextButton } from "$lib/components/buttons";
   import { BottomDiv } from "$lib/components/divs";
   import BeforeContinueModal from "./BeforeContinueModal.svelte";
+  import { requestPubKeyRegistration } from "./service";
 
   import IconKey from "~icons/material-symbols/key";
 
@@ -15,9 +16,15 @@
     console.log(data.privKeyBase64);
   };
 
-  const continueWithoutExport = () => {
+  const continueWithoutExport = async () => {
     isBeforeContinueModalOpen = false;
 
+    const ok = await requestPubKeyRegistration(data.pubKeyBase64);
+    if (!ok) {
+      // TODO
+      return;
+    }
+
     // TODO
   };
 </script>
diff --git a/src/routes/(fullscreen)/key/export/service.ts b/src/routes/(fullscreen)/key/export/service.ts
new file mode 100644
index 0000000..3cef2bc
--- /dev/null
+++ b/src/routes/(fullscreen)/key/export/service.ts
@@ -0,0 +1,12 @@
+import { callAPI } from "$lib/hooks";
+
+export const requestPubKeyRegistration = async (pubKeyBase64: string) => {
+  const res = await callAPI("/api/key/register", {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
+    },
+    body: JSON.stringify({ pubKey: pubKeyBase64 }),
+  });
+  return res.ok;
+};
diff --git a/src/routes/api/auth/login/+server.ts b/src/routes/api/auth/login/+server.ts
index 65f7623..7a4351b 100644
--- a/src/routes/api/auth/login/+server.ts
+++ b/src/routes/api/auth/login/+server.ts
@@ -13,7 +13,7 @@ export const POST: RequestHandler = async ({ request, cookies }) => {
       pubKey: z.string().nonempty().optional(),
     })
     .safeParse(await request.json());
-  if (!zodRes.success) error(400, zodRes.error.message);
+  if (!zodRes.success) error(400, "Invalid request body");
 
   const { email, password, pubKey } = zodRes.data;
   const { accessToken, refreshToken } = await login(email.trim(), password.trim(), pubKey?.trim());
diff --git a/src/routes/api/key/register/+server.ts b/src/routes/api/key/register/+server.ts
new file mode 100644
index 0000000..1c98bb4
--- /dev/null
+++ b/src/routes/api/key/register/+server.ts
@@ -0,0 +1,22 @@
+import { error, text } from "@sveltejs/kit";
+import { z } from "zod";
+import { authenticate } from "$lib/server/modules/auth";
+import { registerPubKey } from "$lib/server/services/key";
+import type { RequestHandler } from "./$types";
+
+export const POST: RequestHandler = async ({ request }) => {
+  const zodRes = z
+    .object({
+      pubKey: z.string().base64().nonempty(),
+    })
+    .safeParse(await request.json());
+  if (!zodRes.success) error(400, "Invalid request body");
+
+  const { userId, clientId } = authenticate(request);
+  if (clientId) {
+    error(403, "Forbidden");
+  }
+
+  await registerPubKey(userId, zodRes.data.pubKey);
+  return text("Public key registered");
+};