The captcha.php library is very user-friendly and extremely easy to integrate into existing forms, because of its simple API. It nevertheless sports many configuration options, like multiple image modes and accessible alternative text riddles. It also has "AJAX" super cow powers and many sensible defaults to frustrate users less than other implementations. It prevents spambot access well, even with its relaxed defaults.
FuzzyIndex indexes text for performing fuzzy searches using PHP and SQLite. It can process a list of text strings and build a database which indexes snippets of those strings and the locations where they appear. The class can also search for given keywords and returns the locations of the indexed strings where the best-matching text appears. It uses SQLite to store the indexed text database, but the class can be extended to use a different database type. It uses certain heuristics to extract the snippets from the indexed text. These heuristics are implemented as separate classes which can be used interchangeably.
Nowadays, a simple password is not enough anymore! Multi-OTP is an OATH-certified PHP class, a Web interface, and a powerful command line tool that can be used to authenticate and manage OTP user tokens for strong two-factor authentication. It can create, update, and delete tokens to authenticate users with one time passwords (OTP). The users' data are stored in files. The class can also check the user token using several algorithms: Mobile OTP (MOTP), OATH/HOTP (RFC 4226), and OATH/TOTP HOTP Time Based (RFC 4226 extension). It works with compatible software tokens (iPhone, Android, PalmOS, Nokia, and other Java J2ME capable phones) and hardware tokens (such as Feitian, ZyXEL, Authenex, or Seamoon). The multiotp command line utility is also provided, both in "compiled" form (for Windows) and in source code (for Linux or educational purpose). The multiotp command line can be combined with FreeRADIUS (under Linux) or the free TekRADIUS LT (under Windows) in order to have a powerful radius strong authentication server.
Multi-byte Keyword Generator extracts meta keywords from multi-byte text. It is an enhanced version of the "Automatic Keyword Generator" class originally written by Ver Pangonilo. This version provides better word segmentation, the ability to handle multi-byte strings, and support for text in multiple languages.
PHP CLI Framework is a simple class which you can extend to quickly create a commandline (CLI) application using PHP. Only a single file is needed, and everything extends that file. It supports interactive input and an object oriented way of writing which keeps things nice and clean. Features include arguments, flags, options, colors, interactive input, object oriented PHP5, a micro framework, and minimal coding required. There's only a single class to extend.