As3 Crypto is a cryptography library written in Actionscript 3 that provides several common algorithms.

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Developer: crypto.hurlant.com
License: Freeware
Operating System: All

Cryptomak is collection of php script for encrypting and decrypting messages (plain or encrypted text)Cryptomak contains some encryptions such as shift, affine, monoalphabetic substitution, vigenere, permutation, and so on.

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Developer: SourceForge.net
License: Freeware
Operating System: All

An anti spam image script written in PHP, generates a code, creates an image out of it, and registers this code in a session.

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Developer: anti-spam-verification-image.googlecode.com
License: Freeware
Operating System: All

Securimage is an open-source free PHP CAPTCHA script for generating complex images and CAPTCHA codes to protect forms from spam and abuse.

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Developer: phpcaptcha.org
License: Freeware
Operating System: All

Vulcan Logic Disassembler hooks into the Zend Engine and dumps all the opcodes (execution units) of a script.

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Developer: pecl.php.net
License: Freeware
Operating System: All

Generic PHP Password Protection is a PHP script that offers easy to install, secure password protection.

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Developer: puremango.co.uk
License: Freeware
Operating System: All

ROT13 Encryption - protect your messages using ROT13 encryption.

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Developer: simple-scripts.net
License: Freeware
Operating System: All

Cryptonit is an encryption tool based on the same Open Source model as IDX-PKI, a model which has revolutionized the market and divided the price of PKIs by 10 in the last two years.

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Developer: SourceForge.net
License: Artistic License, GNU General Public License (GPL)
Operating System: Windows, Linux, Mac OS, BSD, Solaris

This script is a simple C program which basically compares two strings and reports whether they are the same or not.

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Developer: apurvaslair.50g.com
License: Freeware
Operating System: Windows, Linux, Mac OS, BSD, Solaris