What is a jailbreak?

All bought iPhones and iPod touches (and many other devices) are delivered "in a jail", meaning that you cannot install any software on them that is not approved by the manufacturer (Apple in this case). Jailbreaking means to modify your device so that it allows to run any software. This means it is then your choice of what to install. Apple makes it nearly impossible to do this by using digital certificates and crypto hardware built into the device, but some clever people found ways to get around this.
last edit: 2011-01-02

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