A simple PHP verification code implementation code

To improve website security, verification codes are essential for login. A simple and exquisite PHP Verification Code came into being! This verification code is simple and elegant, and the source code is simple. You can customize and modify the style. It is a good verification code.

To improve website security, verification codes are essential for login. A simple and exquisite PHP Verification Code came into being! This verification code is simple and elegant, and the source code is simple. You can customize and modify the style. It is a good verification code.

Implementation Code:

// Save the verification code to the session for global use
Session_start ();
$ Nums = "";
For ($ I = 0; $ I <4; $ I ++ ){
// Generate a random number and convert it to hexadecimal notation
$ Nums. = dechex (mt_rand (0, 15 ));
}
// Write the verification code to the session
$ _ SESSION ['code'] = $ nums;

// Set the length and width of the Verification Code
$ _ Width = 60;
$ _ Height = 20;
// Create an image
$ _ Img = imagecreatetruecolor ($ _ width, $ _ height );
// Create a white
$ _ White = imagecolorallocate ($ _ img, 220,250,250 );
// Fill in the background
Imagefill ($ _ img, 0, 0, $ _ white );

// Draw 6 lines randomly
For ($ I = 0; $ I <6; $ I ++ ){
$ _ Rnd_color = imagecolorallocate ($ _ img, mt_rand (0,255), mt_rand (0,255), mt_rand (0,255 ));
Imageline ($ _ img, mt_rand (0, $ _ width), mt_rand (0, $ _ width), mt_rand (0, $ _ width), mt_rand (0, $ _ width), $ _ rnd_color );
}

// Randomly plot the snowflake
For ($ I = 0; $ I <60; $ I ++ ){
Imagestring ($ _ img, 1, mt_rand (1, $ _ width), mt_rand (1, $ _ height), "*", imagecolorallocate ($ _ img, mt_rand (200,255), mt_rand (200,255), mt_rand (200,255 )));
}

// Output the verification code
For ($ I = 0; $ I Imagestring ($ _ img, mt_rand (6, 10), $ I * $ _ width/4 + mt_rand (1, 10), mt_rand (1, $ _ height/2 ), $ _ SESSION ['code'] [$ I], imagecolorallocate ($ _ img, mt_rand (0,100), mt_rand (0,150), mt_rand (0,200 )));
}

// Output and destroy
Header ("Content-Type: image/png ");
Imagepng ($ _ img );
Imagedestroy ($ _ img );
?>

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