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 It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired.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

A digital signature attached to an email message offers another layer of security by providing assurance to the recipient that you—not an imposter—signed the contents of the email message. Your digital signature, which includes your certificate and public key, originates from your digital ID. And that digital ID serves as your unique digital mark and signals the recipient that the content ...

You can resolve problems with Microsoft Authenticator by checking the tips in this article and reviewing some of the known errors.

Why do I see PIN input rather than biometric for unlock in Microsoft Authenticator? A: If you're using Microsoft Authenticator with an Android or iOS work profile, make sure you add biometrics in your work profile. Biometrics for regular security don't always carry over to work profiles.

If this is the first time you're setting up Authenticator, you might receive a prompt asking whether to allow the app to access your camera (iOS) or to allow the app to take pictures and record video (Android). Allow the app to use the camera so that you can take a picture of a QR code in one step.

Whether it’s a new job title (congratulations!) or a phone number change, make sure you keep your email message signature up-to-date. If you're using new Outlook, for more information about email signatures, or if you haven’t created one yet, see Add a signature to messages. Select File > Options > Mail > Signatures. Select the signature you want to edit, and then make your changes in the ...

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

This page provides support links for home users and support phone numbers for business users.

Learn how to sign in and create app passwords for Microsoft apps and devices that don't support two-step verification.

在Outlook中，您可以為電子郵件建立一或多個個人化簽名。 您的簽名可以包含文字、鏈接、圖片 (影像，例如您的手寫簽名或 ...