Swapnote

Swapnote, aka Nintendo Letter Box in EUR, is an eShop application which allows you to send notes to friends via SpotPass/StreetPass.

Swapnote Extdata

Every note written and received besides the built-in notes are stored in Extdata. There's two extdata files per note, these are created when new notes are saved. Properly recovering cleartext via XOR for the *whole* note data is difficult, since these extdata files would already have the note data stored. The graphics data for these notes are stored via MPOs.