_php Techniques of digital verification Code and digital operation verification code implemented in PHP

The example of this article describes the implementation of PHP digital verification Code and digital operation verification code. Share to everyone for your reference. Specifically as follows:

1. Digital Verification Code:

<?php//The first instance is the digital captcha, the most common authentication code.
How many numbers can be decided by yourself.
$num is the generated verification code containing several digital getvalidate (4,60,20);
  function Getvalidate ($num, $w, $h) {$code = "";
  For ($i =0 $i < $num; $i + +) {$code. = rand (0,9); The//code variable is finally $num a number and is a string.
  Inherited if it is to generate a four-bit digital authentication code, you can use Rand (1000,9999) to generate Header ("content-type:image/png");
  $img = Imagecreate ($w, $h);//Create a picture, the long width parameter is a beginning to define good. $black = Imagecolorallocate ($img, 0,0,0);//define Black $gray = Imagecolorallocate ($img, 200,200,200);//define Grey $bgcolor = Imagecol
  Orallocate ($img, 255,255,255);//Background color white Imagefill ($img, 0,0, $gray);
  Imagefill ($image, ing $x, int $y, int $color), in the image image coordinates x,y with color color to perform area fill/to the verification code to draw a border, the sense of verification code Meimei, in fact, draw a border is to draw him a rectangle
  Imagerectangle ($img, 0,0, $w-1, $h-1, $black)/////////*imagestring ($image, $font, $x, $y, $s, $col) with black frame Use the col color to draw the string s to the X,y (XY is the upper-left coordinate of the string) represented by image the upper-left corner of the entire image is (0,0) if font is 1,2,3,4,5, then use the built-in font *//one is to draw a four digit method, so that four character positions are random and so on $
  Strx = rand (5,10);
    for ($i = 0; $i < $num; $i + +) {$strops = rand (1,6); Imagestring ($img, 5, $strx, $strops, substr ($code, $i, 1), $Black);
    $strx + + rand (8,12); The Strx is the horizontal axis, which needs to be added each time before the coordinates are guaranteed to not overlap. Ordinate no matter if the//SUBSTR () function returns a portion of the string, substr (String,start,length), the string to intercept, the start position, the length to intercept//generate a number, the following to give the verification code region some interference, Prevents some tools from automatically identifying//1. Method One: Add a lot of noise to the background//imagesetpixel ($image, $x, $y, $color), draw a point for ($) in the image image using color in the x,y coordinates (the upper-left corner of the image is 0,0).  i = 0 $i <80; $i + +) {Imagesetpixel ($img, rand (0, $w), rand (0, $h), $black);//These points are distributed in this context}//2. Method Two: Draw a few dashed lines $style
  = Array ($black, $gray);
  Imagesetstyle ($img, $style);
  Imagesetstyle ($image, $style), set the style of the drawing line, the pixel-composed array $y 1 = rand (0, $h);
  $y 2 = rand (0, $h);
  $y 3 = rand (0, $h);
  $y 4 = rand (0, $h);
  Imageline ($img, 0, $y 1, $w, $y 2,img_color_styled);
  Imageline ($img, 0, $y 3, $w, $y 4,img_color_styled);
  Imagepng ($IMG);
Imagedestroy ($IMG);

 }?>

2. Digital Operation Verification Code:

<?php getvalidate (100,30);
  function Getvalidate ($w, $h) {$img = Imagecreate ($w, $h);
  $gray = Imagecolorallocate ($img, 255,255,255);
  $black = Imagecolorallocate ($img, Rand (0,200), Rand (0,200), Rand (0,200));
  $red = Imagecolorallocate ($img, 255, 0, 0);
  $white = Imagecolorallocate ($img, 255, 255, 255);
  $green = imagecolorallocate ($img, 0, 255, 0);
  $blue = imagecolorallocate ($img, 0, 0, 255);
  Imagefilledrectangle ($img, 0, 0, $black);
  for ($i = 0; $i < $i + +) {Imagesetpixel ($img, rand (0, $w), rand (0, $h), $gray);
  $num 1 = rand (1,99);
  $num 2 = rand (1,99);
  Imagestring ($img, 5, 5, rand (1,10), $num 1, $red);
  Imagestring ($img, 5,30,rand (1,10), Getrand (), $white);
  Imagestring ($img, 5,45,rand (1,10), $num 2, $green);
  Imagestring ($img, 5,65,rand (1,10), "=", $blue);
  Imagestring ($img, 5,80,rand (1,10), "?", $red);
  Header ("Content-type:image/png");
  Imagepng ($IMG);
Imagedestroy ($IMG);
  function Getrand () {$code = rand (0,1);
      Switch ($code) {case 0:return "+";
    Break
      Case 1:return "-";
    Break
  Default: # code ... break;

 }}?>

I hope this article will help you with your PHP programming.