If you own a jailbroken iPhone or iPad, you may occasionally want to downgrade to an older firmware. Under such circumstances, you will require what is called the SHSH blob for the older firmware. SHSH blobs are like a unique ID for your device at a particular firmware that is used by Apple to authenticate your device when it is connected to iTunes.
Conventionally, applications like TinyUmbrella are used for this purpose. A new app called iSHSHit has now been released that enables this process to happen directly from the iDevice. iSHSHit is a free download from the BigBoss repository on Cydia and by launching the application, you can choose to save the blob over the Cydia servers with just a simple tap of a button.
Once done, users may also choose to send a backup copy of the SHSH blob to their email address with another tap. The application is extremely simple to use and is quite nifty if you have already jailbroken your iDevice.