THHybridCache Caches UIImage instances in a NSCache Saves UIImage representations on disk as JPGs and PNGs Performs disk writes in a background queue License: MITObjective CTHPinViewController Has iPhone portrait and iPad portrait and landscape layouts Supports variable PIN lengths Buttons can show numbers and letters or only numbers Background and tint colors as well as text and color of the prompt can be customized Supports solid color and translucent/blurred background License: MITObjective C