Although there have been several jailbreak tweaks that allow you to modify your iOS 7 lock screen, developer Dylan Kelly has delivered the most comprehensive one to date. CustomLS lets you hide the various items found on the lock screen and change the "slide to unlock" text. You can download this jailbreak tweak for free from Cydia's BigBoss repository.
Once you've installed customLS, head to Settings->customLS. You'll see a bunch of toggles, so start toggling. The toggles let you hide the items on your lock screen. You can hide both the Notification Center and Control Center grabbers (the little horizontal bars at the top and bottom of the LS). You can hide the camera icon and
the clock. If you disable the clock but still want to be able to see the time, you can enable time in the status bar. You can also disable the slide to unlock slider. If you have hidden the NC, CC or slide to unlock, the functionality is still there, you just can't see them. This is not the case for the camera grabber however.
Another nice feature of customLS is the ability to change the "Slide to Unlock" text, as well as the "legal text", which is the smaller text beneath the slide to unlock text ("Please" in the picture above). To customize either of these, simply enable the text you want to change and enter your own text. You'll have to respring for these changes to take effect.CustomLS requires iOS 7 or better and it is not currently fully compatible with the iPad.