PHP QR Code is a library for generating QR Codes, 2-dimensional barcodes. It is based on the libqrencode C library and provides an API for creating QR Code barcode images (PNG and JPEG).

µTox is the lightweight client with minimal dependencies; it not only looks pretty, it runs fast! µTox is available for Windows, OS X, and Linux (Android support is experimental), with full support for chat, file transfers, audio/video calling, and desktop sharing (both as video and inline screenshots). It also supports text group chats with audio groups pending the next Toxcore update.

A reasonable way to achieve a long term backup of OpenPGP (GnuPG, PGP, etc) keys is to print them out on paper. The reasoning behind this is that paper and ink has amazingly long retention qualities - far longer than the magnetic or optical means that are generally used to back up computer data.

This utility can conceal messages in ASCII text by appending whitespaces to the end of lines. Because spaces and tabs are generally not visible in text viewers, the message is effectively hidden from casual observers. And if the built-in encryption is used, the message cannot be read even if it is detected.