Learn how to identify and open encrypted and protected emails no matter what email client you're using.

Certificate authority (CA) A certificate authority is an entity similar to a notary public. It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired. Top of Page Digital signature assurances The following terms and definitions show what assurances are provided by digital signatures. Authenticity The signer is ...

找尋您需要了解的有關 Xbox 玩家代號的所有資訊。

View message headers in new Outlook Select More actions at the top of the message window. Select View > View message details. Find the sender's address in new Outlook Scroll down in the Message details until you find the From field. Highlight the email address enclosed within < > and right-click to Copy. Use this email address to block the sender. Read how to block or unblock senders.

Learn how to redeem prepaid codes for Xbox games, subscriptions, or downloadable content using your account.

Learn how you can use the free Microsoft Authenticator app to sign in to all your accounts without using a password.

瞭解如何在行動裝置、Windows 裝置或 Xbox 主機上兌換 Microsoft/Xbox 禮品卡或其他代碼。

A BitLocker recovery key is needed when BitLocker can’t automatically unlock an encrypted drive in Windows. This key, which is a 48-digit number, is used to regain access to the drive.

If you’re tired of having to remember or reset your password, try using a FIDO2–compliant security key to sign in to your Microsoft account instead. What is a security key? A security key is a physical device that you can use instead of your user name and password to sign in. Since it needs to be unlocked with a fingerprint or PIN, even if someone has your security key, they won’t be ...

Check the Xbox services, games, and apps for any service outages.