It’s indispensable for businesses running cloud applications but irresistible to cybercriminals, which is why millions of users of Microsoft’s Entra ID authentication server are about to see a major change to the way they log in as Microsoft blocks any type of authentication but passkeys. A close relative of the Microsoft Active Directory system used on internal networks Entra ID – used at over 720,000 businesses – provides single sign-on (SSO) services that let users log on once, then be logged into Office 365 and other cloud systems they’re authorised for. Protecting the keys to the kingdomThe change follows a similar move last year to strike user passwords from Microsoft Authenticator and force users to adopt passkeys instead. Because Entra ID manages the so-called ‘keys to the kingdom’ that control access to every cloud system the company uses, it’s a perennial target for cybercriminals. For the millions of users that use Entra ID every day, the message from Microsoft is clear: from 1 February, the company warns, “users must register a passkey before they can continue signing into their account….