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Novaz AuthenticatorGET

Coincheck 2FA: how to set up an authenticator app

By the Novaz team · Updated October 29, 2026
Novaz steps checked against version 1.0.5

On this page
  1. Save the setup key first
  2. Turn on 2FA on the website
  3. Turn on 2FA in the Coincheck app
  4. When Coincheck asks for a code
  5. If Coincheck rejects your code
  6. Changing phones
  7. If you lose your authenticator
  8. Turning 2FA off
  9. Official Coincheck help

Coincheck is a Japanese crypto exchange, run by Coincheck, Inc., where you buy, sell and send Bitcoin and other coins from the Coincheck app or the website. Coincheck uses the word 2段階認証 (two-step verification) only for codes from an authenticator app. It has no app of its own for this: it recommends Google Authenticator, but says any app that supports the TOTP standard will work (Coincheck). This guide uses Authenticator App - Novaz on iPhone. Any authenticator app works the same way.

Signing in always needs a second step of some kind. If you haven't set up an authenticator app, Coincheck may send a text message (SMS) code to your phone number instead (Coincheck, Coincheck). The help center is only in Japanese, so the labels below are copied from it, with our translation in parentheses. The English version of the site may word them differently.

How we checked this guide: the Coincheck steps come from Coincheck's own help center, in Japanese, linked below, which we read on October 21, 2026. We haven't tested them on a Coincheck account, so a label may differ slightly. The Novaz steps are checked against the app, version 1.0.5.

Save the setup key first

Coincheck shows its セットアップキー (setup key) only once, while you set up 2FA. It can't show you the same key again later. Coincheck asks you to keep a copy, because the key is how you rebuild your codes on another phone if yours is replaced, reset or broken (Coincheck).

With Novaz it matters too: unless you turn on iCloud backup or keep a backup file, Novaz's keys exist only on your iPhone. Keep the key in a password manager or on paper, away from your phone. Coincheck doesn't mention backup codes, so this key is your backup.

Turn on 2FA on the website

Coincheck describes this flow for a computer and a phone (Coincheck):

  1. Sign in on the website and open 設定 (settings), then 2段階認証 (two-step verification). On a phone browser, the gear icon sits under the menu icon at the top right (Coincheck).
  2. Click 設定する (set up). Coincheck emails you a confirmation link. Click it soon, because a delay can make it fail.
  3. Coincheck now shows the setup key and a QR code. Save the key first.
  4. In Novaz, tap +, then Scan QR code, and point the camera at the code on screen. If the QR code is on the iPhone you're using, take a screenshot, then tap + and Choose a photo (see scanning a QR code on the same iPhone).
  5. Type the 6-digit code from Novaz and click 設定する again. The page then says the setting is done (設定済).

Turn on 2FA in the Coincheck app

The app gives you the key to copy instead of a QR code (Coincheck, Coincheck):

  1. At the bottom, tap 本人確認 (identity verification) or ウォレット (wallet), then the person icon at the top right.
  2. Tap 設定 next to the warning, or 2段階認証設定　未設定 > (two-step verification: not set).
  3. Tap the button next to ①セットアップキーをコピー (copy the setup key) and save the key somewhere safe.
  4. Coincheck's 認証アプリを起動 (open authenticator app) button lists apps to open. Instead, open Novaz yourself, tap +, then Enter key manually, and paste the key into Setup key. Put "Coincheck" in Service. See What is a 2FA setup key?
  5. Back in Coincheck, enter the code in ③6桁の認証コードを入力 (enter the 6-digit code). You should see 2段階認証設定が完了しました (setup complete).

Coincheck's codes are 6 digits and change every 30 seconds (Coincheck), which is what Novaz uses for a typed key. Its help doesn't say how long the key is. Novaz needs at least 16 characters, so if it refuses the key, use the website's QR code.

When Coincheck asks for a code

With 2FA on, Coincheck asks for a code when you sign in, when you create or renew an API key, and when you change your registered phone number (Coincheck).

If you also set up a passkey, you sign in with the passkey instead of a code. Coincheck says you may still need the authenticator code for some actions, such as sending crypto or changing your details, so don't delete the Coincheck entry from Novaz (Coincheck).

If Coincheck rejects your code

Coincheck's own advice: enter the newest code, wait for a fresh code if the current one is about to change, and check that your phone sets its clock automatically. It warns that a drift of even a dozen seconds can break codes (Coincheck). On iPhone, open Settings > General > Date & Time and turn on Set Automatically. Novaz also warns you when the clock is 15 seconds or more off. More causes are in Authenticator code not working?

Changing phones

Coincheck's route is the saved setup key: add it to the authenticator app on the new phone, then check that you can sign in. If you have no copy of the key, sign in with the old phone, turn 2FA off, and set it up again on the new one (Coincheck). With Novaz, add the saved key on the new iPhone with Enter key manually. If you have a Novaz iCloud backup or backup file, restoring it on the new iPhone brings Coincheck back too. See How to transfer your authenticator app to a new iPhone.

If you lose your authenticator

If you have a Novaz iCloud backup or backup file, restore it on the new iPhone. If you saved the setup key, you can also add it to Novaz on another iPhone. If you have neither, Coincheck has a self-service reset (Coincheck):

  1. Sign in with your email address and password.
  2. On the code screen, tap 認証コードがエラーになる / 不明の場合 (if the code fails or you don't know it). On the website it reads パスコードがエラーになる／不明の場合.
  3. Tap 解除手続きに進む (continue to turn it off). Coincheck emails you a link.
  4. Open the link, wait for a text message, and enter the 6-digit SMS code.

This only works if your registered email address and phone number haven't changed and you can receive both. Otherwise, or if the button doesn't appear, contact support through the inquiry form and choose ログイン > 2段階認証 > 2段階認証を解除したい (I want to turn off two-step verification). Coincheck doesn't say how long support takes.

If your phone was lost or stolen, Coincheck can also restrict trading on your account so no one else can use it (Coincheck). More in Lost the phone with your authenticator app?

Turning 2FA off

You can only turn it off in a browser, not in the Coincheck app. Sign in on the website, go to the two-step verification page, enter a code, and click 設定解除 (remove setting). Afterwards, sign-ins fall back to SMS codes unless you use a passkey. Turning it off also cancels the old setup key, so delete the Coincheck entry in Novaz with Remove account before you set it up again (Coincheck, Coincheck).

Official Coincheck help

These pages are in Japanese. Titles are translated.

More guides: Crypto exchanges and wallets