Apple added two-step authentication support to iCloud on Tuesday, and also announced that app-specific passwords for the online service will be available starting on October 1. App-specific passwords will let users assign unique passwords to apps that need access to iCloud without having to hand over their primary login and potentially give full access to everything in their account.
iCloud gets app-specific passwords next month
iCloud's app-specific passwords will limit third party apps and services to access only the part of the service that lets them do what their supposed. Apple said iCloud users can create up to 25 app-specific passwords. Alternate calendar apps, for example, can be limited to only your schedule data.
You can create app-specific passwords through Apple's My Apple ID webpage, then click Password & Security. Fron there, click Generate App-Specific Password. Apple also has a support article detailing app-specific passwords.