en popüler forum & blogların captcha larını kıran botlarım war zaten
@tyranid
dediğin yöntem zaten kullanılmakta
php.net e not ekleyenlere two minus one? gibi sorular soruluyor
bir de şey war mp3 captcha
Captcha Talk A captcha with speech
mp3 + swf captcha

<?php
// swfmovie.php - swf output and config
session_start();
/********************************************************************************
* Note: sample includes depending on the PHP version
* Use formprotect.php on PHP 5 
* Use swfcaptcha4.php on lower PHP versions
********************************************************************************/
if (version_compare(phpversion(), "5.0.0", ">=")) { 
	include_once('classfile/swfcaptcha.php');
} else { 
	include_once('classfile/swfcaptcha4.php');
} 
$swfc = new swfcaptcha();
// SWF OPTIONAL USER OPTIONS - SEE CLASS ALSO
/*
		// Default colors for characters
	$swfc->colors = array('EE0000','00EE00','0000EE','00EEEE','EEEE00','EE00EE');
		// Default background color
	$swfc->bgcolors = array('000000');
		// Swf movie width and height
	$swfc->swf_width = 210;
	$swfc->swf_height = 75;
		// Offset for char movie in main swf movie
	$swfc->swf_x = 10;
	$swfc->swf_y = 50;
		// Scale char movie in main movie
	$swfc->x_scale = 5;
	$swfc->y_scale = 5;
		// Space between chars in char movie
	$swfc->font_width = 30;
		// Thickness of font lines in char movie
	$swfc->font_line = 65;
		// Captcha char lenght
	$swfc->captcha_length = 6;
		// Time settings for animation: draw - still display and rotate
	$swfc->drawtime = 70;
	$swfc->stilltime = 3000;
	$swfc->rotatetime = 150;
		// different animation type = 0, 1, 2, 3
	$swfc->animation = 3;
		// animation scale to ( from zero to scale )
	$swfc->animateoffset = 0;
		// y float, 0 = off ( value is random y axis movement )
	$swfc->animatefloat = 5;
		// Default fonts to use - empty is read all .fdb fonts from font dir
		// Note: only .fdb fonts
	$swfc->font = array('Arial.fdb','EtcEtc.fdb');
	$swfc->fontdir = "font";
		// Free bitstream vera fdb fonts - http://ming.sourceforge.net/
		// Default background image ( optional )
		// jpg - png or gif ( NB this Ming function is buggy with jpg's )
		// $bgimages empty and $bgimgauto true is autoscan dir for images
	$swfc->bgimages = array();
	$swfc->bgimgauto = false;
		// Default dir to background images
	$swfc->imagesdir = "images";
		// Default dir to sounds 
	$swfc->sounddir = "sounds";
		// Language folder user defined (  country code lowercase )
		// All sound files have a prefix: msc_ - except the starting sound codestart.mp3
	$swfc->soundlang = "";
		// Movie frame rate
	$swfc->framerate = 12;
		// Frames for dound duration - depends on framerate
		// Experiment with values for correct sound duration
	$swfc->soundframes = 25;
		// Sample sounds 22kc 1.5 sec mono mp3
		// use DNSBL check if dnsblist is not empty and usednsbl = true
		// set in class file
	$swfc->forbidden_img = "forbidden.gif";
		// On DNSBL listed - generate an error sound ( from sound dir )
	$swfc->forbidden_sound = "forbidden.mp3";
*/
$swfc->swfmovie();
?>

$swfc nin alt değerlerini rand vererek kırılma olasılığını azaltabilirsiniz