The general idea is as follows:
- Create an Xposed module that hooks into Snapchat much like KeepChat or SnapShare and encrypt the photo/video using PGP before sending
- Recipient will decrypt it and view as normal
There are already tools that can manage the keys such as AGP.
This idea can even go as far as quickly delivering any kind of encrypted data by embedding the data inside the image and using SnapChat's fast server as the delivery mechanism. The data can be saved using the same method as KeepChat.
(I am not quite sure on the legality of using Snapchat's servers to send small files other than images and videos.)
This will make for a nice way of quickly "emailing" documents and files to others.
This information may be out of date or useless but here goes.
File type and size limit: Any data (server does not care) so long as it is <= 1 MB - Source
Encryption is used (AES) so a possible way of accomplishing this without breaking Snapchat is to encrypt the data with PGP then hand it off to Snapchat to encrypt it with its own encryption scheme. This will make it easier to maintain, if any, for future updates of Snapchat. - Source
SnapShare can be modified (with the permission of the developer of course) to select any files <=1 MB and KeepChat's code can be used to store and decrypt the payload so much of the code already exists and is mostly just making a mashup of AGP, KeepChat, and SnapShare.
This whole concept is just steganography using Snapchat as the medium and method of delivery. Snapchat itself is fast, offers easy to use user interface, and already has a large enough audience. If this project picks up, maybe more people will become aware of the usefulness of PGP.