Few things attract new users to an app more than the ability to interact with other people; gamers demand multi-player and socialites want instant photo sharing. To ease the burden of exchanging data fluidly, Samsung has released its new Chord SDK to make local peer-to-peer and group communication much easier for developers with little or no networking knowledge. It exposes features similar to Samsung's AllShare SDK, but makes it possible to broadcast data and share files with several devices at once.
Chord automates the discovery of nearby devices and handles most of the tedious aspects of file transfer and messaging, which are built on top of the open source ZeroMQ library for high efficiency. The library provides an abstract system of public and private "channels" for connecting with other devices, all over Wi-Fi and Wi-Fi Direct. While most of the complexities are handled internally, security and encryption are left for developers to hash out on their own. Samsung is also distributing an Eclipse plug-in for testing purposes. The documentation states that you can simulate communication between a computer and a device or between two computers with emulators running.
The library requires Android 4.0+ (API level 14), and - allow me to state the obvious - Chord will only work on devices with TouchWiz. Despite the fact that this is an OEM exclusive, it's a great way to get started without having to write all of the networking code from scratch. If you've got the next great sharing app or multi-player game flashing before your eyes, hit Samsung's developer portal to check out the downloads and sample code.