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PHP captcha code generation, submission and verification

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PHP Code Submission & Verification:
The following code is for the submission and verification of the captcha code entered by user and redirect the user to an other page.

<?php
print '<html><head><link type="text/css" rel="stylesheet" href="http://localhost/php/account/photo.css"/><title>Captcha</title></head><body>';
$error = NULL;
if (isset($_REQUEST['confirm_code'])) {
    if (isset($_COOKIE['Captcha'])) {
        list($Hash, $Time) = explode('.', $_COOKIE['Captcha']);
        if (md5("OASDOIJQWOIJDASDOI" . strtoupper($_REQUEST['confirm_code'] . $_SERVER['REMOTE_ADDR'] . $Time)) != $Hash) {
            $error = '<marquee behavior="slide" direction="up" width="100%" height="2.5%" style="text-align: center;" id="pop-up"><div width="100%" style="text-align: center;"><em>Invalid Captcha Code!</em></div></marquee>';
        } elseif ((time() - 5 * 60) > $Time) {
            $error = '<marquee behavior="slide" direction="up" width="100%" height="2.5%" style="text-align: center;" id="pop-up"><div width="100%" style="text-align: center;"><em>Captcha code is only valid for 5 minutes!</em></div></marquee>';
        } else {
            if (isset($_GET[md5("signup")]))
                die(header("location:http://localhost/php/account/upload.php?" . md5("signup")));
            else
                die(header("location:http://localhost/php/account/login.php?" . hash('sha256', 'cookies')));
        }
    } else {
        $error = '<marquee behavior="slide" direction="up" width="100%" height="2.5%" style="text-align: center;
                    " id="pop-up"><div width="100%" style="text-align: center;
                    "><em>No captcha cookie given. Make sure cookies are enabled!</em></div></marquee>';
    }
}
if (isset($_GET[md5("signup")])) {
    print '<div id="main" align="center"><form method="post"><div style="background-color: #009CE8;"><img src="http://localhost/php/account/easycaptcha.php"/><br />
                    Enter code from above image: <input type = "text" autofocus name = "confirm_code" maxlength = "5"/><br /><a href = "?' . md5("refresh") . '" > Try another code?</a><br />
                    <hr></div><input type = "submit" value = "Submit"/></form></div></body></html>' . $error;
} else {
    //print $hd;
    print '
                    <style>
#main{
                    background-color: #009CE8;
                    color: white;
                    }
                    </style>
                    <div id = "main" align = "center">
                    <span id = "error">You must login before viewing this page. This for the safety of the contents of the page.<br>
                    <a href = "http://localhost/php/account/login.php">Click Here To Login</a>
                    </span>
                    </div>';
}
?>

easycaptcha.php Contains the following script:

<?php
require('php-captcha.inc.php');
$fonts = array('', 'Bd', 'BI', 'It', 'MoBd', 'MoBI', 'MoIt', 'Mono', 'Se', 'SeBd');
for ($i = 0; $i < count($fonts); $i++)
    $fonts[$i] = 'fonts/Vera' . $fonts[$i] . '.ttf';//define your own font path
$alphabet = 'A_B_C_D_E_F_G_H_I_J_K_L_M_N_O_P_Q_R_S_T_U_V_W_X_Y_Z_0_1_2_3_4_5_6_7_8_9';
//a_b_c_d_e_f_g_h_i_j_k_l_m_n_o_p_q_r_s_t_u_v_w_x_y_z;
$alphabet = explode('_', $alphabet);
shuffle($alphabet);
$captchaText = '';
for ($i = 0; $i < 5; $i++) {
    $captchaText .= $alphabet[$i];
}
$time = time();
setcookie('Captcha', md5("OASDOIJQWOIJDASDOI" . $captchaText . $_SERVER['REMOTE_ADDR'] . $time) . '.' . $time, null, '/');
$oVisualCaptcha = new PhpCaptcha($fonts, strlen($captchaText) * 23, 60);
$oVisualCaptcha->UseColour(true);
$oVisualCaptcha->CaseInsensitive(true);
$oVisualCaptcha->SetHeight(100);
$oVisualCaptcha->SetWidth(280);
$oVisualCaptcha->SetMaxFontSize(38);
$oVisualCaptcha->SetMinFontSize(28);
$oVisualCaptcha->Create($captchaText);
?>

php-captcha.inc.php contains the following code:

<?php
session_start();
define('CAPTCHA_SESSION_ID', 'php_captcha');
define('CAPTCHA_WIDTH', 200); // max 500
define('CAPTCHA_HEIGHT', 50); // max 200
define('CAPTCHA_NUM_CHARS', 5);
define('CAPTCHA_NUM_LINES', 70);
define('CAPTCHA_CHAR_SHADOW', false);
define('CAPTCHA_OWNER_TEXT', '');
define('CAPTCHA_CHAR_SET', ''); // defaults to A-Z
define('CAPTCHA_CASE_INSENSITIVE', false);
define('CAPTCHA_BACKGROUND_IMAGES', '');
define('CAPTCHA_MIN_FONT_SIZE', 16);
define('CAPTCHA_MAX_FONT_SIZE', 25);
define('CAPTCHA_USE_COLOUR', false);
define('CAPTCHA_FILE_TYPE', 'jpeg');
define('CAPTCHA_FLITE_PATH', '/usr/');
define('CAPTCHA_AUDIO_PATH', '/tmp/');
class PhpCaptcha {
    var $oImage;
    var $aFonts;
    var $iWidth;
    var $iHeight;
    var $iNumChars;
    var $iNumLines;
    var $iSpacing;
    var $bCharShadow;
    var $sOwnerText;
    var $aCharSet;
    var $bCaseInsensitive;
    var $vBackgroundImages;
    var $iMinFontSize;
    var $iMaxFontSize;
    var $bUseColour;
    var $sFileType;
    var $sCode = '';
    function PhpCaptcha(
    $aFonts, $iWidth = CAPTCHA_WIDTH, $iHeight = CAPTCHA_HEIGHT
    ) {
        $this->aFonts = $aFonts;
        $this->SetNumChars(CAPTCHA_NUM_CHARS);
        $this->SetNumLines(CAPTCHA_NUM_LINES);
        $this->DisplayShadow(CAPTCHA_CHAR_SHADOW);
        $this->SetOwnerText(CAPTCHA_OWNER_TEXT);
        $this->SetCharSet(CAPTCHA_CHAR_SET);
        $this->CaseInsensitive(CAPTCHA_CASE_INSENSITIVE);
        $this->SetBackgroundImages(CAPTCHA_BACKGROUND_IMAGES);
        $this->SetMinFontSize(CAPTCHA_MIN_FONT_SIZE);
        $this->SetMaxFontSize(CAPTCHA_MAX_FONT_SIZE);
        $this->UseColour(CAPTCHA_USE_COLOUR);
        $this->SetFileType(CAPTCHA_FILE_TYPE);
        $this->SetWidth($iWidth);
        $this->SetHeight($iHeight);
    }
    function CalculateSpacing() {
        $this->iSpacing = (int) ($this->iWidth / $this->iNumChars);
    }
    function SetWidth($iWidth) {
        $this->iWidth = $iWidth;
        $this->CalculateSpacing();
    }
    function SetHeight($iHeight) {
        $this->iHeight = $iHeight;
        if ($this->iHeight > 200)
            $this->iHeight = 200;
    }
    function SetNumChars($iNumChars) {
        $this->iNumChars = $iNumChars;
        $this->CalculateSpacing();
    }
    function SetNumLines($iNumLines) {
        $this->iNumLines = $iNumLines;
    }
    function DisplayShadow($bCharShadow) {
        $this->bCharShadow = $bCharShadow;
    }
    function SetOwnerText($sOwnerText) {
        $this->sOwnerText = $sOwnerText;
    }
    function SetCharSet($vCharSet) {
        if (is_array($vCharSet)) {
            $this->aCharSet = $vCharSet;
        } else {
            if ($vCharSet != '') {
                $aCharSet = explode(',', $vCharSet);
                $this->aCharSet = array();
                foreach ($aCharSet as $sCurrentItem) {
                    if (strlen($sCurrentItem) == 3) {
                        $aRange = explode('-', $sCurrentItem);
                        if (count($aRange) == 2 && $aRange[0] < $aRange[1]) {
                            $aRange = range($aRange[0], $aRange[1]);
                            $this->aCharSet = array_merge($this->aCharSet, $aRange);
                        }
                    } else {
                        $this->aCharSet[] = $sCurrentItem;
                    }
                }
            }
        }
    }
    function CaseInsensitive($bCaseInsensitive) {
        $this->bCaseInsensitive = $bCaseInsensitive;
    }
    function SetBackgroundImages($vBackgroundImages) {
        $this->vBackgroundImages = $vBackgroundImages;
    }
    function SetMinFontSize($iMinFontSize) {
        $this->iMinFontSize = $iMinFontSize;
    }
    function SetMaxFontSize($iMaxFontSize) {
        $this->iMaxFontSize = $iMaxFontSize;
    }
    function UseColour($bUseColour) {
        $this->bUseColour = $bUseColour;
    }
    function SetFileType($sFileType) {
        if (in_array($sFileType, array('gif', 'png', 'jpeg'))) {
            $this->sFileType = $sFileType;
        } else {
            $this->sFileType = 'jpeg';
        }
    }
    function DrawLines() {
        for ($i = 0; $i < $this->iNumLines; $i++) {
            if ($this->bUseColour) {
                $iLineColour = imagecolorallocate($this->oImage, rand(100, 250), rand(100, 250), rand(100, 250));
            } else {
                $iRandColour = rand(100, 250);
                $iLineColour = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);
            }
            imageline($this->oImage, rand(0, $this->iWidth), rand(0, $this->iHeight), rand(0, $this->iWidth), rand(0, $this->iHeight), $iLineColour);
        }
    }
    function DrawOwnerText() {
        $iBlack = imagecolorallocate($this->oImage, 0, 0, 0);
        $iOwnerTextHeight = imagefontheight(2);
        $iLineHeight = $this->iHeight - $iOwnerTextHeight - 4;
        imageline($this->oImage, 0, $iLineHeight, $this->iWidth, $iLineHeight, $iBlack);
        imagestring($this->oImage, 2, 3, $this->iHeight - $iOwnerTextHeight - 3, $this->sOwnerText, $iBlack);
        $this->iHeight = $this->iHeight - $iOwnerTextHeight - 5;
    }
    function GenerateCode() {
        $this->sCode = '';
        for ($i = 0; $i < $this->iNumChars; $i++) {
            if (count($this->aCharSet) > 0) {
                $this->sCode .= $this->aCharSet[array_rand($this->aCharSet)];
            } else {
                $this->sCode .= chr(rand(65, 90));
            }
        }
        if ($this->bCaseInsensitive) {
            $_SESSION[CAPTCHA_SESSION_ID] = strtoupper($this->sCode);
        } else {
            $_SESSION[CAPTCHA_SESSION_ID] = $this->sCode;
        }
    }
    function DrawCharacters() {
        $palette = array();
        for ($i = 0; $i < 10; $i++) {
            if ($this->bUseColour) {
                if ($this->bCharShadow)
                    $palette[$i] = imagecolorallocate($this->oImage, 225, 225, 225);
                else {
                    $palette[$i] = imagecolorallocate($this->oImage, 225, 225, 225);
                }
            } else {
                if ($this->bCharShadow)
                    $palette[$i] = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);
                else {
                    $iRandColour = rand(0, 100);
                    $palette[$i] = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);
                }
            }
        }
        for ($i = 0; $i < strlen($this->sCode); $i++) {
            $sCurrentFont = $this->aFonts[array_rand($this->aFonts)];
            $iTextColour = $palette[array_rand($this->aFonts)];
            $iFontSize = rand($this->iMinFontSize, $this->iMaxFontSize);
            $iAngle = rand(-30, 30);
            $aCharDetails = imageftbbox($iFontSize, $iAngle, $sCurrentFont, $this->sCode[$i], array());
            $iX = $this->iSpacing / 4 + $i * $this->iSpacing;
            $iCharHeight = $aCharDetails[2] - $aCharDetails[5];
            $iY = $this->iHeight / 2 + $iCharHeight / 4;
            imagefttext($this->oImage, $iFontSize, $iAngle, $iX, $iY, $iTextColour, $sCurrentFont, $this->sCode[$i], array());
            if ($this->bCharShadow) {
                $iOffsetAngle = rand(-30, 30);
                $iRandOffsetX = rand(-5, 5);
                $iRandOffsetY = rand(-5, 5);
                imagefttext($this->oImage, $iFontSize, $iOffsetAngle, $iX + $iRandOffsetX, $iY + $iRandOffsetY, $iShadowColour, $sCurrentFont, $this->sCode[$i], array());
            }
        }
    }
    function WriteFile($sFilename) {
        if ($sFilename == '') {
            header("Content-type: image/$this->sFileType");
        }
        switch ($this->sFileType) {
            case 'gif':
                $sFilename != '' ? imagegif($this->oImage, $sFilename) : imagegif($this->oImage);
                break;
            case 'png':
                $sFilename != '' ? imagepng($this->oImage, $sFilename) : imagepng($this->oImage);
                break;
            default:
                $sFilename != '' ? imagejpeg($this->oImage, $sFilename) : imagejpeg($this->oImage);
        }
    }
    function Create($inText = false, $sFilename = '') {
        if (!function_exists('imagecreate') || !function_exists("image$this->sFileType") || ($this->vBackgroundImages != '' && !function_exists('imagecreatetruecolor'))) {
            return false;
        }
        if (is_array($this->vBackgroundImages) || $this->vBackgroundImages != '') {
            $this->oImage = imagecreatetruecolor($this->iWidth, $this->iHeight);
            if (is_array($this->vBackgroundImages)) {
                $iRandImage = array_rand($this->vBackgroundImages);
                $oBackgroundImage = imagecreatefromjpeg($this->vBackgroundImages[$iRandImage]);
            } else {
                $oBackgroundImage = imagecreatefromjpeg($this->vBackgroundImages);
            }
            imagecopy($this->oImage, $oBackgroundImage, 0, 0, 0, 0, $this->iWidth, $this->iHeight);
            imagedestroy($oBackgroundImage);
        } else {
            $this->oImage = imagecreate($this->iWidth, $this->iHeight);
        }
        imagecolorallocate($this->oImage, 0, 156, 232);
        if ($this->sOwnerText != '') {
            $this->DrawOwnerText();
        }
        if ($inText === false)
            $this->GenerateCode();
        else {
            $this->sCode = $inText;
            $this->SetNumChars(strlen($inText));
        }
        $this->DrawCharacters();
        $this->WriteFile($sFilename);
        imagedestroy($this->oImage);
        return true;
    }
    function Validate($sUserCode, $bCaseInsensitive) {
        if ($bCaseInsensitive) {
            $sUserCode = strtoupper($sUserCode);
        }
        if (!empty($_SESSION[CAPTCHA_SESSION_ID]) && $sUserCode == $_SESSION[CAPTCHA_SESSION_ID]) {
            unset($_SESSION[CAPTCHA_SESSION_ID]);
            return true;
        }
        return false;
    }
}
?>

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