Use the Information Protection viewer to view protected files in Windows, Android, iOS, or Edge.

About digital signatures and certificates in Office, and buying a digital certificate from a certificate authority or create your own.

Want to add a padlock to your email messages? You can use encryption and digital signatures in new Outlook, classic Outlook, and Outlook on the web for work or school accounts to increase the security of messages. Encrypting an email message in Outlook means it's converted from readable plain text into scrambled cipher text. Only the recipient who has the private key that matches the public ...

The Microsoft Authenticator app helps you sign into your accounts when you're using two-step verification.

See how to view the details for signatures and certificates.

Note: This article is intended primarily for Windows Pro and Home users. For IT professionals or enterprise IT-managed devices, refer to IT admin guide: Secure Boot certificate update status in the Windows Security app.

How to create or edit your Outlook signature for email messages. Include your signature, text, images, electronic business card, and logo.

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 It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired.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 ...

什么是安全启动？ 安全启动是统一可扩展固件接口中的一项安全功能， (基于 UEFI) 的固件，可帮助确保只有受信任的软件在设备的启动 (启动) 序列中运行。 它的工作原理是针对存储在设备固件中的一组受信任的数字证书 (（也称为证书颁发机构或 CA) ）验证预启动软件的数字签名。 作为行业标准 ...

Using Authenticator as a way to sign in If you have turned on passwordless, two-step, or multi-factor authentication for your account, use the following steps to sign-in: Go to the site where you want to sign in. Enter your username at the sign-in prompt and select Next. Select Send notification.