There must have been some change of guard at Apple.iOS6.1 adds again tougher protections although public JB community hasn’t broken iOS6 yet
Historically, Apple has been fairly tough on security exploits. It wasn’t uncommon for a new version of iOS to be available a day or two after a public release of a new jailbreak tool which used a security exploit within iOS to install Cydia and other packages.
Apple does actively search for security exploits in iOS, though they rarely make it a priority. With the above statement as evidence, it seems as if Apple has made locating such issues in iOS a high-priority item. Apple has been stepping up their security teams, following a few, limited issues (mostly within OS X and not iOS) earlier this year that allowed for malware to be installed on users’ computers.
So while added security measures are certainly not a bad thing, it doesn’t bode well for jailbreakers. As iOS 6.1 nears release, those hoping to jailbreak their devices are advised to stay on iOS 6 for as long as possible.