RC4/ARCFOUR Implementation in PHP

I wrote this RC4/ARCFOUR implementation in PHP – based on the original C source code posted on usenet in 1994. The rc4() call itself is completely self-contained, two other methods rc4_test() and rc4_benchmark() have been provided for testing and are optional.
My motivation for writing it was to replace the dependency on MCrypt in my SpamKit plugin for WordPress – see Gerry‘s site for the updated TBT code I will wrap in the next SpamKit Plugin release.
This is software is completely public domain, all I ask for is a simple credit for my work if you find it useful.
View Source: rc4.php
View Source: rc4tests.php
Examples:
1. Simple encryption & decryption
[php]< ?php require_once( "rc4.php" ); $key = "0123456789abcdef"; $plaintext = "Hello World!"; $ciphertext = rc4( $key, $plaintext ); $decrypted = rc4( $key, $ciphertext ); echo $decrypted . " - " . $plaintext . "\n"; ?>[/php]
2. Execute the tests and display the results
[php]< ?php require_once( "rc4tests.php" ); // Auto includes rc4.php echo rc4_tests(); ?>[/php]
3. Execute the tests as benchmarks and display the results
[php]< ?php require_once( "rc4tests.php" ); // Auto includes rc4.php echo rc4_benchmark(); ?>[/php]

3 thoughts on “RC4/ARCFOUR Implementation in PHP”

  1. TBTs: SpamKit_Token v1.3

    I spotted a “bug” in the TBT code for SpamKit this week when using the awesome power of google. It appears that building PHP with mcrypt support is not that common, which means spamkit causes a fatal error when trying to generate your TBT…

  2. Fair cop, guv…
    A quick test with error_reporting (E_ERROR | E_WARNING | E_PARSE | E_NOTICE); shows no others.
    It didnt fail the test cases for it, but it caused a ‘E_NOTICE’ warning from PHP. Source code above has been updated.

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