To everyone's surprise, Apple removed support for iCloud Keychain from GM-release iOS 7, which was released September 10. Although at WWDC was promised to support this function, iOS 7, apparently the final version of "Seven", which will be released in the coming days, this feature we will not see.
On a page of the Apple website dedicated to the new features iOS 7, it is noted that the function of iCloud Keychain will "soon" available on mobile OSes kupertinovtsy. It is possible that it was decided to postpone the launch of the final release of OS X Mavericks, who also needs to get a "bunch of keys". It is obvious that at the same time with the release of Mavericks, Apple released iOS update, which will include this feature.
For the first time, Apple said the new iCloud features in June at the WWDC-2013. Keychain is a password manager and personal data, which are stored in the "cloud" and available at any Apple device operating iOS 7 and OS X Mavericks.
It is expected that the final version of OS X Mavericks will be released this fall, while public build of iOS 7 will be available for download from September 18.