iOS 8.1.1 jailbreak was released last week by a team of Chinese hackers called TaiG, and the well-known hacker MuscleNerd vouched for the fact that she is safe for use by iDevice owners.
In an extremely extensive text published on the famous website reddit, the creator of Cydia, saurik, spoke in detail about everything he thinks about iOS 8.1.1 jailbreak TaiG and what its use might entail from the point of view of user security. saurik claims throughout his statement that TaiGJailbreak is most likely a safe software for users, but the lack of information regarding the team behind it leaves things in some uncertainty.
But, as I've stated before, I don't think "trust" comes down to these explicit checks: a real back door would not be something obvious, but would be a subtle bug left in the software that the original developers knew how to exploit. I thereby turn to high-level thoughts, as I think that's the only way to model something as squishy as "trust".
In this idea, he says that if TaiGJailbreak really contained a backdoor that would allow access to user data, it would be difficult to discover with a simple analysis and its existence would be revealed some time after the release. However, considering that MuscleNerd has confirmed that the jailbreak solution is safe, saurik believes that a confirmation from this hacker should be taken with absolute confidence, despite the controversies surrounding the jailbreak.
There are enough people using it to hopefully catch "phoning home" issues. So, the app is probably safe. But, if you are really wanting to know "saurik's opinion", here it is: I am not the person who can answer the question of whether to trust this tool or not, and you might be better off asking people like MuscleNerd, who has apparently decided to sign off on it not doing anything malicious.
Additional details about Saurik's opinion can be found in this page, but summarizing everything I will tell you that he leaves everything in the hands of MuscleNerd, and if TaiGJailbreak will contain malware or data theft software, the accusations will go to the well-known iPhone Dev Team hacker.
